Ohio Grape-Wine Short Course 1992 Proceedings Horticulture Department Series 630 '5 I The Ohio State University Ohio Agricultural Research and Development Center Wooster, Ohio S2._ This page intentionally blank. PREFACE Approximately 150 persons attended the 1991 Ohio Grape-Wine Short course, which was held at the Radisson Hotel in Columbus on February 23-25. Those attending were from 9 states, not including Ohio, and represented many areas of the grape and wine industry. This course was sponsored by the Department of Horticulture, The Ohio State University, Ohio Agricultural Research and Development Center, Ohio Cooperative Extension Service, Ohio Wine Producers Association and Ohio Grape Industries Committee.

All publications of the Ohio Agricultural Research and Development Center are available to all potential clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, sex, age, handicap, or Vietnam-era veteran status. 10/91-500 TABLE OF CONTENTS Page Cultivar Characteristics of Ohio Vinifera Grapes by G.A. Cahoon, D.M. Scurlock, G.R. Johns, and T.A. Koch 1 Managing Vinifera Varieties for Improved Fruit Quality by David V. Peterson ...... 9 Wine Characteristics of Some Newer Varietals in Ohio by Roland Riesen ...... 16 A Little Wine Knowledge Goes a Long Way by Murli Dharmadhikari ...... 20 Growing Vinifera in Northeast Ohio by Arnu 1f Esterer ...... 32 Trends in Wine Grape Production in the Finger Lakes Region by David V. Peterson ...... 44 Take Another Look at Juice Clarification by J.F. Gallander, R. Riesen and J.F. Stetson ...... 51 Small Things Can Mean A Lot: ML Strains for Wines by Roland Riesen ...... 55 DUI As a Problem and Some of the Answers by Maj . D. G. Goodman ...... 66 Sensory Evaluation of Spoiled Wines by Murl i R. Dharmadhi kari ...... 73 Grape Spray Schedule for Controlling Diseases and Insects by M.A. Ellis, R.N. Williams, and C. Welty ...... 81 Grape Phylloxera by Murdick J. Mcleod and Roger N. Williams 92 CULTIVAR CHARACTERISTICS OF OHIO VINIFERA GRAPES G. A. Cahoon, D. M. Scurlock, G. R. Johns and T. A. Koch Department of Horticulture, The Ohio State UniversityfOARDC Wooster, Ohio Ohio has a long history of grape production: approximately 170-190 years. This history is well documented and will not be discussed in further detail. However, interspersed in this history from the earliest date are the continued trials, successes and failures of growers to produce V. vinifera (1,3,4,5,6). Whether it be modern technology, more hardy clones or cultivars, or favorable climatic conditions, the last 15 years have seen the greatest successes with vinifera in Ohio that we have ever known. Today the acreage of vinifera in Ohio is between 150 and 200 acres. This is by far the largest it has ever been and growers are very optimistic about its future. The information I wish to present to you today includes information from 5 studies conducted at various places throughout Ohio during my tenure at OSU the past 28 years. Experiment I Experiences with V. vinifera in Southern Ohio during the 1970-76 period were not very successful (2). Six cultivars: Cabernet Sauvignon, Chardonnay, Gewurztraminer, Pinot Noir, White Riesling, and Zinfandel were obtained from University of California, Davis and planted in 1970. Ten additional cultivars were also obtained from the U.S. Plant Introduction Station in Maryland. These were primarily table grapes. The vines produced fruit from 1973-1976 but were plagued by winter injury and crown gall throughout the experiment. Severe injury incurred during the winter of 1976-77 and terminated the experiment. During the four production years average yields for the wine cultivars were 11.2 lbs/vine or 3.38 tons/acre (605 vines/acre). Zinfandel had the highest average production with 19.7 lbs/vine or 6 tons/acre but the lowest brix and highest acids (14.6° Brix and 1.16% TA, respectively). Other yields, brix and acids were: Cabernet Sauvignon, 10.2 lbs/vine, 17.8° Brix and 0.91% titratable acids (TA); Chardonnay, 6.2 lbs/vine, 19.8° Brix and 0.84% TA; Gewurztraminer, 10.8 lbs/vine, 19.9° Brix and 0.77% TA; Pinot Noir, 11.5 lbs/vine, 17.9° Brix and 1.02% TA; White Riesling, 8.6 lbs/vine, 17.6° Brix and 0.97% TA. Production from the additional 10 introductions was less successful than the California selections and generally fruited only 2 of the 4 years (1973- 76)(2). Experiment II In 1975 a collection of 34 numbered vinifera selections were obtained from the breeding program of Dr. Harold Olmo, University of California, Davis. The goal was to test these selections for their climatic adaptation and disease susceptibility in Southern Ohio. This experiment yielded very little information other than the fact that V. vinifera was much less winter hardy

1 and more difficult to grow than the labruscana or French hybrid cultivars under trial at this time. It was found that a numbered selection, eventually named Carmine, now being grown at the Grape Research Branch, Kingsville, was the most hardy of the numbered group under the Southern Ohio environment. Experiment III In 1978 ten (10) White Riesling clones were imported from the Landes-Lehr­ und Versuchsanstalt Fur Landwirtschaft, Trier, Germany. These clones were kept in isolation (quarantine) for 3 years to check for virus and other disease infections. In 1983 four plantings were established at 4 locations in Ohio: (1) The Southern Branch of the Ohio Agricultural Research and Development Center, Ripley, Ohio; (2) The Overlook Branch of OARDC, Carroll, Ohio; (3) The Main campus of OARDC, Wooster, Ohio and; (4) Chalet Debonne', Madison, Ohio. (Figs 1-3). Each of these plantings contained a total of 200 vines: 5 replications of 5 clones on 2 rootstocks. Clones included in the experiment were: Geisenheim 110, Weis 21B, Heinz 65, Niederhausen 378 and Newstadt 90. Vines were planted 10 feet between rows and 7 feet between vines in the row. Yield results for the years 1985-88 and 1991 will be presented. Experiment IV In 1985 a series of V. vinifera cultivars were planted at the Grape Research Branch, Kingsville, Ohio (Figs 4-5). Included were: Gamay Beaujolais, Gewurtztraminer, Merlot, Pinot Nair, Chardonnay, Carmine, White Riesling, Cabernet Sauvignon, Aligote, Muscat Ottonel, Muller Thurgau, Rkatsiteli, Green Veltliner and Pinot Menier. Northern Ashtabula County, near Lake Erie, has some of the best climate for grapes in the state and is the county with the largest production. Yield and quality results for the years 1988-91 are presented. Experiment V In 1986 a second V. vinifera experiment was initiated at the Grape Research Branch (Figs 6-8). This planting contained the cultivars White Riesling and Cabernet franc, grafted on 7 rootstocks, plus own-rooted vines. The rootstocks were: C.3309, Mgt.101-14, T.5C, C.1616E, SO 4, 18-815, Kober 5BB. Yield and quality results for one year (1991) are presented. RESULTS AND DISCUSSION Experiment III The initial production was obtained in the fall of 1985 and averaged only 4.91 lbs/vine (1.53 tons/acre). Table 1 shows the combined yield and quality characteristics for the four production locations for the four year period, 1985-88. Differences among the clones and rootstocks are not presented for this period. The highest average yields were produced in the Debevc vineyard at the Madison (Northeast) location (5.05 T/A). This was followed by the Overlook branch, Carroll (Central) location (4.83 T/A) and the Main campus, Wooster (North Central) (3.64 T/A). The lowest yield was produced at the 2 Southern Branch, Ripley (Southern) (2.21 T/A). Low productivity at the Ripley location was primarily related to spring frosts which severely reduced the crop during one season. However, cluster number was the greatest and berry and cluster weight the smallest at the Ripley location. Brix and acids content were highest at the Carroll (Central) and Wooster (North Central) locations and lowest at Ripley (Southern). The Madison (North East) location was intermediate. Table 1. Production Characteristics of Five White Riesling Clones Grown at Four Locations in Ohio, 1985-1988 Clone Southern Br Overlook Br. Main Campus Debevc (Ripley) (Carro 11) (Wooster) (Madison)

Yield -T/Acre 2.21 4.83 3.64 5.05 Clust. No. 133 92 63 87 Clust Wt. gm 43 77 85 94 Wt./Berry gm 0.90 1.11 1.40 1.09 0 8rix 17.3 19.2 19.1 18.6 Total Acids % 0.64 0.88 1.00 0.88

As can be observed by Table 2, yields at these same locations for 1991 were similar. Differences among clones were not taken at the Madison location. Combined production for all clones at this location was estimated to be 6.11 tons/acre. The 1991 season had an average production for all clones at the 4 locations of 4.01 tons/acre. In general, this was typical of several previous years. Results for the 5 clones at 3 locations shows that average production (tons/acre) was highest for Clone Gm 110 (3.56 tons) and lowest for Neustadt 90 (2.95 tons). This was also characteristic of the results when all years and all locations were considered (tables for individual years are not presented). Table 2. Production in Tons/Acre of 5 White Riesling Clones Grown at 4 Locations in Ohio, 1991. Southern Overlook Main Campus Debevc Clone (Ripley) (Carroll) (Wooster) (Madison) Average Tons/Acre Gm 110 3.07 3.55 3.42 3.56 Weis 218 2.99 3.76 3.76 3.51 Heinz 65 3.32 3.76 3.14 3.39 Neder. 378 3.23 4.04 2.68 3.33 Neustadt 90 2.80 3.58 2.49 2.95 Average 3.09 3.74 3.10 6.11 4.01

3 This experiment was continued through 1991 at which time plantings were removed at the Southern and Overlook Branches and the Main campus. The most pertinent information the experiment yielded was that after a period of 13 years all four plantings were good, productive vineyards. It should also be pointed out that weather conditions these vineyards experienced ranged from years with winter temperatures of -20 to -24 degrees F., to spring frosts, to severe droughts to seasons with excessive rainfall. In addition the vineyards covered geographical areas in the state from south to north; Ripley, near the Ohio river in the south, to Madison, near Lake Erie in the north east. Experiment IV This cultivar block was established in 1985 and had its first production in 1988. Yields in tons/acre are presented for the 4-year period, 1988-1991. The soil is a silt loam, typical of the area where most of the grapes are grown in Ashtabula and Lake Counties. Growth has been quite acceptable for all cultivars although productivity was variable. The major acreage of labruscana grapes (Concord, Niagara and Catawba) is located in Ashtabula and Lake Counties. Prices paid and production for these cultivars range between $200 and $300 per ton with yields of 5 to 9 tons per acre. By contrast prices per ton currently paid for vinifera cultivars were substantially greater but production per acre is generally less. To put these differences into perspective Table 3 presents yield characteristics for this 4-year period and prices currently paid for these cultivars, plus estimated returns per acre based upon these production averages. Table 3. Production Characteristics of V. vinifera grapes: 1988-1991, Grape Research Branch, Kingsville, Ohio. Cult i var Clust. No. Clust. Wt. Tons/A $/Ton $/Acre

Gamay B 62 .12 3.08 1,250 4,158 Gewurtz. T 37 .12 1. 79 1,360 2,417 Mer lot 60 .14 3.58 1,700 6,086 Riesling 49 .13 2.47 980 2,421 Chardonnay 54 .20 4.34 1,400 6,076 Muscat Ott.** 50+ .09+ 1.87+ 1,360 2,540+ Muller T. 47 .21 3.91 950 3' 717 Aligote'* 96 .14 5.55 1,360 7,548 Green Velt.* 82 .14 4.66 950 4,430 Rkatsitel i* 28 .15 1.71 1,150 1,965 P. Meunier* 85 .08 2.78 1,350 3,761 * 3 years data **Bird damage Experiment V Vines for this experiment were planted in 1986. Initial production was obtained in 1988. However, data will only be presented for the 1991

4 production season. It compares yield and fruit characteristics for both White Riesling and Cabernet franc cultivars when grafted on 7 rootstocks, plus own­ rooted vines. As can be observed by tables 4A and 4B, differences among the clones were obtained. Also, the rootstocks did not affect both cultivars in the same manner. For example, yield, cluster number and brix were generally lowest for own-rooted vines of both cultivars. Yield and cluster number for Riesling was highest when grafted on C.l616E while Cabernet franc produced its highest yield when grafted on SO 4. However, some of the same trends did exist among the rootstocks. It will be obvious to those familiar with such research that production results from several more years will be required to provide the level of validity and confidence necessary for the experiment to have real value. Table 4A. Production and maturity characteristics of White Riesling grapevines grown on 7 rootstocks plus own-rooted vines; 1991, Grape Research Branch, Kingsville, Ohio.

Rootstock Yield Cluster Cluster Berries/ Berry 0 Bri x pH TA ( l bs) No. Wt. ( l bs) Cluster Wt. ( gm) %

Own Root 7.2e BOb .09 46.3 0.92d 15.4c 3.10 O.BO C.3309 10.3d 94ab .11 46.3 1.12bc 17.7ab 3.30 0.72 MgtlOl-14 10.6cd lOOab .11 52.0 1. 07bc 17.3ab 3.20 0.71 T.5C 11. 5bcd lOOab .12 4B.3 l.l6b 17.4ab 3.30 0.75 1B-Bl5 12.4abcd lOlab .13 56.0 0.99cd 17.3ab 3.30 0.79 K.5BB 13.0abc BOb .13 53.1 1.3Ba 1B.4a 3.30 0. 71 so 4 13. 2ab 103a .13 60.3 1.11 be 16.Bb 3.30 0.76 C.l616E 14.7a 115a .17 57.2 1.05bcd 17.5ab 3.30 0.74

Table 4B. Production and maturity characteristics of Cabernet franc grapevines grown on 7 rootstocks plus own-rooted vines; 1991, Grape Research Branch, Kingsville, Ohio.

Rootstock Yield Cluster Cluster Berries/ Berry 0 Bri x pH TA ( l bs) No. Wt. ( l bs) Cluster Wt. ( gm) %

Own Root 5.6c 73c .OB 30.6 l.l2d 17.7b 3.3 0.65 C.3309 9.7ab 92ab . 11 40.6 1.19abc 1B.7ab 3.4 0.67 Mgt. 101-14 9.0b B2bc . 11 41.9 1. 22bc 14.6a 3.4 0.67 T.5C 10.Ba 91ab .12 45.2 1.24ab 1B.9ab 3.4 0.69 1BB-15 10. 1ab B9abc .12 44.0 1.20cd 18.0b 3.4 0.73 K.5BB 9 .lab 82bc .12 40.3 1.30a 18.9ab 3.4 0.71 so 4 10.9a lOOa .11 40.3 1. 24abc 17.9b 3.4 0.66 c .1616[ 10.4ab 89abc .12 42.4 1.30cd 18.6ab 3.4 0.70

5 CONCLUSIONS By far the most significant conclusion to be drawn from these data is that several V. vinifera cultivars are being grown successfully in Ohio and in more than one geographical locations in the state. However, regardless of the geographical area, the most favorable microclimates must be carefully selected for any vineyard, especially one to be planted to the vinifera species. The next most significant conclusion relates to the level of production that can be expected from vinifera cultivars. For French and American hybrids production levels of 5-6 tons per acre or above are generally necessary to obtain an adequate economic return per acre. For the vinifera cultivars it can be observed that the same or even a superior monetary return can be obtained at lower production levels. This relationship is very desirable because high production generally relates to greater physiological stresses and reduced fruit quality and winter hardiness. To determine the best rootstock for a given cultivar is difficult. Soil type and texture, temperature and moisture and many other factors must be considered. Yet it is important to know the range of effects that various rootstocks can produce on the important cultivars grown in an area. Results from the rootstock experiment presented here has produced some early data of value in that the various rootstocks gave a range of yield and quality results. Most significant was the information that vines on all rootstock varieties in the experiment produced a greater yield than the control vines, i.e., those not grown on a rootstock. As mentioned previously more years of data will be required to show just how important some of these rootstocks can be to long range production for the Riesling and Cabernet franc cultivars. LITERATURE CITED 1. Cahoon, G. A. 1984. The Ohio Wine Industry from 1860 to the Present. American Wine Society Journal 16(3):82-86,94 2. Cahoon, G. A. 1985. Grape Cultivar Research. Horticulture Department Series 554-A. 3. Dufour, John James 1826. The American Vine-Dreser' s Guide Being a Treatise On The Cultivation On The Vine And The Process Of Wine-Making Adapted To The Soil And Climate Of The United States. J. S. Brown. Cincinnati, Ohio. 4. Hedrick, U. P. 1908. The Grapes of New York. State of New York. Department of Agriculture, Fifteenth Annual report, Vol. 3, Part II. J. B. Lyon Co. State Printers. 5. McGrew, John, R. 1984. A Brief History of Grapes and Wine in Ohio to 1865. American Wine Society Journal 16(2):38-41. 6. Sifritt, Susan K. 1976. The Ohio Wine and Grape Industries. Ph.D dissertation, Kent State University.

6 Fig. 1 . Riesling Clone Experiment, Chalet Debonne', Madison, 0.

Fig. 2. Riesling Clone Experiment, Horticulture Unit II, OARDC, Wooster, 0.

Fig. 3. Riesling Clone Experiment, Horticulture Unit II, OARDC, Wooster, 0.

Fig. 4. Vinifera Cultivar Experiment Grape Research Branch, OARDC, Kingsville, 0.

7 Fig. 5. V\nifera Cultivar Experiment Grape Research Branch, OARDC. Kingsville, 0.

Fig. 7. Riesling/Cabernet Rootstock Experiment, Grape Research aranch, OARDC, Kingsville, 0.

Fig. 6. Riesling/Cabernet Rootstock Experiment. Grape Research Branch, OARDC, Kingsville, 0.

Fig. 8. Riesling/Cabernet Rootstock Experiment, Grape Research Branch, OARDC, Kingsville, 0. MANAGING VINIFERA VARIETIES FOR IMPROVED FRUIT QUALITY David V. Peterson Area Extension Specialist Finger Lakes Grape Program Penn Yan, New York 14527 INTRODUCTION After so many years of concentrating on getting vinifera to survive in the Northeastern United States, being asked to speak about growing for improved quality indicates a sign of progress in itself. Over the past few decades, we have been able to identify some of the varieties and rootstocks best suited to the rigors of our climate, and have learned a great deal about the differences in management requirements for viniferas compared to the traditional native American and hybrid varieties. For this discussion, I will be reviewing what we know about soils, varieties and canopy microclimate considerations and their relationship to wine quality. ROLE OF COLD INJURY Before getting to these topics, however, it is difficult not to provide some mention of the importance of how cold injury itself can relate to wine quality. One of the key factors affecting quality of any grape variety is the balance between the amount of vegetative growth and crop yield. Excessive production of either is generally at the expense of the other, and can reduce quality. Significant primary bud mortality results in lower fruitfulness and a balance is shifted towards vegetative growth. This growth is often excessive with the lack of fruit to balance it, generally resulting in shading of the fruit and poor wood maturation, which can aggravate the cycle by predisposing this wood to greater cold injury the following season. Proper site selection is critical to the success of any vinifera planting in the Northeast. So often I see vinifera planted on a site because the grower happened to own the land. Not choosing the best possible site is frequently a ticket to quality as well as economic problems. In evaluating cold hardiness of a particular variety, we should also recognize that the relative hardiness depends on when the cold spell occurs. Various varieties have different patterns in cold acclimation (attaining hardiness) and being to lose hardiness at different times in the late winter and early spring. For example, Cabernet Sauvignon generally takes longer to reach its state of maximum hardiness than Riesling. However, it also retains its ability to resist cold longer than Riesling in the late winter. By March in the Finger Lakes, for example, Cabernet is considered to have greater bud hardiness than Riesling and in some cases even Concord. It is difficult to categorize varieties by any one cold hardiness rating because of these differences in patterns of acclimation and deacclimation. Riesling might be considered more cold hardy than Cabernet for the first two thirds of the winter, and then less cold hardy for the last third. Knowing when cold injury events typically occur in any given region will be helpful in making a decision which varieties are best suited to the area.

9 SOILS We frequently hear the Europeans talk at great length about the importance of their soils in making great wines. In spite of this, the specific aspects of what it is about the soil that results in great wines are not really discussed in detail. This probably indicates how little is really known about the relationship, and the argument always comes up as to whether the effects of soil are direct, or just an effect of soil on the growth of the vine and ultimately the microclimate in the vineyard. Sometimes you hear about the benefits of a high lime content, or often vineyardists will claim they can actually taste or feel greatness in the soil. These are all debates that will likely continue for decades if not longer. The difficulty in isolating soil factors that can contribute to improve wine quality will surely cloud this debate for some time. In spite of these uncertainties, there is much that has been learned and several soil factors that should be considered in managing vinifera. Internal soil drainage is important to growing any variety, but is even more critical with vinifera. Excessively wet sites or sections of a field are almost certain to experience greater cold injury and resulting crown gall. Growers in the Finger Lakes frequently put in patterned tile systems with as close as 50 feet between lines, and some feel it should be even closer in extremely heavy soils. Soil pH is also recognized to be critical for successful vinifera production in the Northeastern United States. Viniferas tend to be quite different than native American varieties in their requirements and tolerance of various soil nutrient balances (or imbalances). The viniferas as a group tend to be less tolerant of low pH than American varieties. At very low soil pH, high and possibly toxic levels of aluminum and manganese are found. Aluminum toxicity is known to be associated with poor root growth on a number of crops. Acid soils are also typically low in magnesium. The European literature refers to foliar symptoms associated with low pH (known as Saureschaden in Germany). Greenhouse studies have shown restricted root growth and poorer overall growth with low pH. Viniferas grown on acidic soils in New York have not only been subject to poor growth, but also greater cold injury. Excessively high potassium concentrations in the fruit (which can lead to poorly colored, unstable wines) also often occur on low pH soils. Although potassium availability is theoretically reduced at low soil pH, the low magnesium status of acidic soils results in high potassium uptake. Raising the pH with soil applications of dolomitic limestone is generally the best corrective measure on acidic soils. This is most efficiently accomplished with a preplant application and incorporation of the limestone. Our preplant recommendation for viniferas in New York is targeted for soil pH 6.5-7.0. Surface application after planting can be effective in raising the pH of the rooting zone, but it takes several years. Lime applications to existing vineyards also can induce potassium deficiency. For this reason, applications to existing vineyards should not exceed 2-3 tons lime/acre/year and potassium status should be carefully monitored with petiole testing.

10 Rather than looking at one element, the role of pH is most likely the effect on the overall nutrient balance, macro as well as micronutrients. Monitoring by soil and petiole analysis is critical to the survival of the vine as well as quality of the fruit. GRAPE VARIETY Choosing the proper variety for the site and region is perhaps the most important viticultural factor that will affect wine quality. One must not only consider if the variety has the potential to make high quality wine, but will it make high quality wine where you plan to grow it. Also, marketability and economics of production as well as winter survival and length of season required to ripen the variety are all important to the total production package. In the Finger Lakes, the industry seems to have settled primarily on Chardonnay and Riesling as the major areas of emphasis for vinifera white wine production. These varieties have proven superior to most alternatives in terms of winter survival, sustained economic yields, and consistent fruit quality. From a marketing perspective, these are also recognized varietal names to the wine drinking public. Gewurztraminer, though considered to be less cold hardy than Chardonnay and Riesling, has performed quite will in the vineyard in the Finger Lakes and has produced some outstanding wines. Interest is increasing somewhat in this variety, and it is expected to have an important future, but on a smaller scale than Chardonnay and Riesling. Other varieties of limited commercial interest are Pinot blanc and Muscat Ottonel. Pinot blanc has been successful in the vineyard and has been marketed successfully on a limited scale for champagne production. Muscat Ottonel, though having a reputation for being quite cold tender, has performed very well in several commercial plantings. This variety is of interest primarily in Muscat dessert wines in blending in small proportions to enhance fruitiness. Siegerrebe, an extremely early ripening variety that produces an aromatic wine somewhat reminiscent of Gewurztraminer, and Pinot gris have performed reasonably well in plantings at the Geneva Station, but interest is limited by lack of consumer recognition and wine quality generally below the standard commercial varieties already being grown. Pinot gris may have some limited interest as part of a sparkling wine base, and Siegerrebe may be of interest in very short season areas. Some of the not recommended varieties included Sauvignon Blanc, Ortega, Optima, Sylvaner and Reichensteiner for reasons of low cold hardiness and extreme sensitivity to bunch rots. Several aromatic Riesling-types have looked reasonably good in the Geneva trials, but none would appear to offer significant viticultural or enological advantages over Riesling and all would seem to be at a marketing disadvantage compared to Riesling. The consensus for viniferas is somewhat more confused than the whites. A number of wineries over the past decade made a commitment to Pinot noir as the red wine grape for the Finger Lakes. This movement has slowed as problems

11 with bunch rots and inconsistent wine quality has diminished enthusiasm somewhat. Winemakers have discovered how difficult good Pinot nair is to make even in good years and the uncertainty as to which clone to plant has confused the issue further. Many of the clones planted have turned out to be excellent for champagne, but for various reasons have not been outstanding for red wine. Some rot before they become fully ripe, others have inadequate color, body or flavors for superior wines. A large clonal evaluation study, under the direction of Dr. Robert Pool at Cornell University's New York State Agricultural Experiment Station in Geneva, is underway to evaluate a number of these clones. This is a continuing study and more clones are added as they become available. Of those that are currently in production, Clevener Mariafeld has been one of the more rot-resistant clones and has produced consistently high wine quality. Unfortunately, it has also been one of the more cold tender of the Pinot clones. The feeling is that the best Pinot noir red wines would likely be produced from a mix of several clones, as is done in Burgundy. Gamay Beaujolais, in reality a Pinot clone, although considered a lower quality, but quite fruity Pinot by itself, might be part of a clonal blend. This clone has also performed quite well in the vineyard. Once considered to be too cold tender and too late ripening for the Finger Lakes, the Bordeaux red wine varieties (Merlot, Cabernet Sauvignon, Cabernet franc) are now being planted in significant quantities in the region. Favorable seasons over most of the last decade and improved growing techniques have resulted in good vineyard performance and promising wine quality. Merlot has perhaps the greatest potential in terms of wine quality, but it is also significantly less cold hardy than either of the Cabernets. Cabernet Sauvignon is the latest ripening of the three, but can produce outstanding wines in good years and has good consumer recognition as a varietal. Cabernet franc appears to ripen slightly earlier than Cabernet Sauvignon and may be somewhat more cold hardy. Wine quality has been excellent and its future is for blending with the other Bordeaux reds as well as for a varietal appears to be very good in the Eastern United States. On a more limited scale there is increasing commercial interest in Gamay noir (the true Gamay), Lemberger and perhaps Carmine. Gamay noir has been a reliable producer of good, but probably not outstanding red wines. The good yields and reliable production would indicate at least limited opportunities for increased planting. Lemberger, a lessor known variety that is grown in Germany, has been high yielding and has consistently produced some of the highest rated red wines made at the Geneva Station. Cold hardiness has been similar to some of the less hardy Pinot clones, although yields and wine scores have been better. Resistance to bunch rot has been better than most of the Pinots. Carmine is a University of California-Davis cross, with Cabernet Sauvignon, Carignane and Merlot in its breeding. Wines have been high in tannins and have been promising, but there are some indications that cold hardiness may be somewhat lower than the Cabernets. CANOPY MICROCLIMATE Canopy management seemed to be the hottest topic in viticulture over the past decade. The topic is really very broad and relates to any management practice that ultimately influences the microclimate within the grapevine 12 canopy. A listing of some of these factors might include: site selection, variety, rootstock, vine spacing, fertilization, irrigation, trellis system, training system, pruning (winter and summer), shoot positioning, shoot thinning, cluster thinning and leaf removal. When we talk about canopy microclimate, we are generally concerned with the amount of shading that can occur within the canopy, shading of leaves and shoots as well as fruit. Vinifera, by its nature, is quite vigorous on most sites and can produce very dense, shaded canopies if not managed properly. Before discussing any of the specific practices themselves, a brief review of some of what we know about shading within the canopy is useful. There are numerous studies from throughout the world that have dealt with various aspects of this subject. Perhaps the most significant detrimental effect of shading in the Northeastern United States is that it fosters conditions conducive to bunch rots. Exposed fruit has greater air flow surrounding it and dries more quickly after a rain or heavy dew. Shading in red wine varieties also generally results in less color development. Other factors sometimes associated with shading include increased malic acid, potassium and pH, and decreased soluble solids and aroma components. There is no one method of successfully managing vinifera for optimum exposure. There is also no consensus as to how much exposure is optimal. Excessive exposure to direct sunlight, for example, can cause sunburning of the fruit. Opening up the canopy to increase airflow and allowing at least indirect light to reach the clusters, however, should be a goal in raising vinifera. With this in mind, I will discuss a few vineyard management practices that can be utilized by growers to accomplish this goal: training, summer pruning and leaf removal. The way these practices are used and the impact they will have on fruit quality depends on the density of shoots and leaves within the canopy to begin with. A very dense canopy will derive more benefit from some of these practices than a sparser, more exposed canopy. A number of different training systems are successfully utilized in New York for vinifera. Both high and low head systems are common. The trend, however, has been toward a low head system with upright catch wires. Depending on the variety and the site, low cordon has been used. Low head cane systems such as Pendelbogen and other modifications are also common. Cabernet Sauvignon and Cabernet franc appear to adapt well to low cordon, while most of the other varieties have generally performed best on cane systems. High cordon systems (Hudson River Umbrella) have been problematic with all vinifera varieties due to the difficulty in renewing after cold lnJury. Catch wires are critical with the low head training systems or the shoots with droop later in the season, resulting in shading and much of the fruit close to the ground. Topping of the shoots once they grow above the top wire is also often necessary, or they will eventually droop and shade the canopy. Leaf removal has become more common on the west coast and is practiced in some vinifera vineyards in New York. The process is labor intensive, and, therefore, expensive. Leaf removal machines are now commercially available, however. Whether by hand or by machine, leaf removal is probably most efficient when done on vines trained to a low system with upright catch wires,

13 creating a very defined fruit zone. The idea is obviously not to remove all leaves, just some of those in the fruit zone. If the fruit is distributed all over the trellis, such as with an Umbrella Kniffin trained vine, the time requirement by hand would be cost prohibitive. To avoid excessive leaf removal, the machine must be operated in a specific area of the trellis, thereby making a very defined fruit zone a necessity. Proper timing of leaf removal is not totally agreed upon. Early removal, just after fruit set has been suggested as optimal, but significant regrowth in the fruit zone can occur, making a second pass later in the season necessary. Delaying the operation until just prior to veraison (color change) generally eliminates this problem. Waiting until after veraison can result in significant sunburning of the newly exposed fruit, and the benefits are also likely to be reduced the longer you wait. Most growers in New York are doing their leaf removal in the summer, usually in July or perhaps early August. Summer pruning is a more popular practice in New York vineyards than leaf removal, probably because it is more economical. Many growers already have mechanical hedgers for their winter pruning operations. Summer pruning is also adaptable to any of the major training systems. Top and side cuts are generally made, the width and height is dependent on the canopy itself. With low training systems that utilize catch wires, a top cut is all that is usually necessary. Timing should be dependent on when the canopy gets too dense. One to two passes per year are what is generally practiced. If only one pass is to be made, waiting until the fruit is about 3-4 degrees Brix (just prior to the first Rovral spray) has been effective for many growers. This maximizes fruit exposure so that the Rovral spray gives better coverage. Complete coverage of the cluster with Rovral is critical to the effectiveness of this chemical against bunch rot. Summer pruning earlier in the season usually results in significant regrowth from lateral shoots and may cause the canopy to be denser than it would have been if no summer pruning had been done. Very dense canopies may require early hedging, but it should be recognized that a second pass will likely be necessary. There are a couple of drawbacks to summer pruning. The first has already been pointed out, the regrowth of laterals. Continued summer pruning also tends to have a devigorating effect on the vine and may, therefore, cause a loss in productivity. A loss in vine size may be an advantage up to a point with excessively vigorous vines, but growers should be careful not to let this go too far. Assessment of the amount of growth that has occurred, as in taking pruning weights, for example, is also more difficult with summer hedged vines, since some of the growth has been cut off. One last point regards vine spacing. There is much discussion about using close vine spacing to reduce vigor, and thus create a more open canopy. Most research indicates that this is possible, but that spacing between rows must also be reduced in order to create adequate competition. If this is not done, the shoot density will likely be even greater than if the vines were planted at standard spacing. Since most growers are not willing to reduce row width because of equipment considerations, the standard 6-8 feet between vines

14 within the row continues to provide the best results on most Finger Lakes sites.

SUMMARY Managing vinifera wine grape for improved quality is really not any different in concept than growing other types of grapes. Proper variety and site selection should be the first and probably the most critical decision that a grower must make. The challenge in raising vinifera and the increased range of problems associated with vinifera production in the Northeast makes proper management of these varieties critical. The canopy characteristics of any vineyard will be affected by nearly every operation, starting with the site selection and carrying through right up to the time of harvest. Recognizing this from the beginning will help you avoid problem canopies that require expensive extra management operations. The vines should be managed with the goal of avoiding excessive shade within the canopy, which is especially critical for minimizing the hazard of bunch rot.

15 WINE CHARACTERISTICS OF SOME NEWER VARIETALS IN OHIO Roland Riesen Department of Horticulture The Ohio State UniversityjOARDC Wooster, OH 44691

The cultivar trial for the enology and viticulture program of the Ohio Agricultural Research and Development Center (OARDC) is located in North Kingsville on Lake Erie. The varieties under test include: Chardonnay Cabernet Sauvignon White Riesling Cabernet Franc Gewurztraminer Merlot Muller-Thurgau Carmine Muscat-Ottonel Pinot Noir Pinot Gris Pinot Meunier Pinot Blanc Gamay Green Veltliner Aligote Rkatsiteli

The viticultural aspects have been dealt with during a previous talk at this conference. Besides recording the ripening profile for each variety by analyzing the standard parameters soluble solids, pH and TA berry samples are taken weekly starting with veraison and frozen for later extraction and analysis of the volatile composition. Wine is made routinely using standard vinification techniques and subject to sensory evaluation by trained staff at OARDC and the winemakers of Ohio. The wines presented at this tasting are selected from the 1990 and 1991 vintage. The analysis data (must and wine) with ample space for comments are listed on the tasting sheet. Enjoy!

16 OARDC EXPERIMENTAL WINES - OHIO GRAPE-WINE SHORT COURSE '92 JUICE WINE Residual Alcohol Vineyard WINE Brix TA pH Sugar % TA ___ pH (% vol.) Location Year Harvest Date Green Veltl iner 17.6 . 63 3.22 dry .66 3.28 9.8 Kingsville 91 9/9/91 NOTES:

Pinot Blanc 19.6 . 60 3.33 dry .58 3.23 11.0 Kingsville 91 9/9/91 NOTES:

Pinot gris 17.2 . 68 3.10 dry .49 3.20 11.8 N.Bass Is. 91 8/28/91

'--J NOTES:

Pinot gris-cuipra 17.2 .68 3.10 dry . 49 3.23 11.7 N.Bass Is . 91 8/28/91 NOTES: OARDC EXPERIMENTAL WINES - OHIO GRAPE-WINE SHORT COURSE '92 JUICE WINE Residual Alcohol Vineyard WINE Brix TA pH Sugar% TA pH (% vol.) location Year Harvest Date Pinot Noir Blanc 17.4 1.03 3.44 0.5 .85 3.29 8.9 Kingsvi 11 e 90 10/6/90 NOTES:

Aligote 18.2 .78 3.15 dry .72 3.23 8.9 Kingsville 91 9/9/91 NOTES:

Vignoles 23.7 .83 3.13 1.0 .70 3.16 10.4 Wooster 91 9/11/91

--' co NOTES:

Cabernet Franc Rose 19.0 .76 3.23 0.3 .62 3.28 10.9 Kingsvi 11 e 91 9/10/91 NOTES: OARDC EXPERIMENTAl WINES - OHIO GRAPE-WINE SHORT COURSE '92 JUICE WINE Residual Alcohol Vineyard WINE Brix TA pH Sugar% TA pH (% vol.) location Year Harvest Date Carmine 16.0 1.03 3.25 dry .57 3.60 9.8 Kingsville 90 10/18/90 NOTES:

Kir Imperial .57 3.37 12.3 NOTES:

I.C NOTES:

NOTES: A LITTLE WINE KNOWLEDGE GOES A LONG WAY Murli Dharmadhikari State Fruit Experiment Station Southwest Missouri State University Mountain Grove, Missouri The science of winemaking is a complex subject. A winemaker needs to have a good understanding of the various principles and practices involved in winemaking. I would like to present some information about the following important winemaking practices. 1. Importance of using clean fruit. 2. Proper rehydration of yeast and inoculation of must. 3. Wine aeration and its adverse effects. 4. Use of inert gases in winemaking. 5. Proper use of sulfur dioxide. 1. Use of Clean Fruit There is a common cliche that says "a wine is made in the vineyard". This recognizes the fact that high quality fruit is essential for making good wine. To emphasize the same point further, we can say that a wine is made in the vineyard and sometimes it also is ruined in the vineyard. This is especially true if the grapes are allowed to spoil (in the vineyard), and then used for making wine. In order to make good wine, it is important that only clean fruit be used. Certain sweet wines such as sauternes of France and Beerenauslese and Trocken beerenauslese of Germany are made from grapes infected by the mold called Botrytis cinerea. The rot caused by this mold is commonly known as 'noble' rot. Under very special microclimatic conditions (temperature of 20- 250c, relative humidity of 85-95% for a maximum of 24 hours, followed by a drop in relative humidity below 60%), the mold causes unique changes in fruit composition. These changes include dehydration of berries resulting in a concentration of sugars, flavors, and other constituents; reduction in acid content; increase in pH; formation of gluconic acid, glycerol, polysaccharides, and the characteristic aromas. Because of the modifications in fruit composition mentioned above, the winemakers can produce sweet white wines of great distinction and quality. Under certain climatic conditions, (such as high humidity), the same mold causes fruit rot and also creates conditions favorable for invasion by other harmful micoorganisms. It is important to have a clear distinction between 'noble' rot, caused by Botrytis and the ignoble fruit rot caused by Botrytis and other organisms. The spoilage rot caused by Botrytis and other spoilage organisms is commonly referred to as bunch rot or sour bunch rot. The fungus Botrytis cinerea infects the berry and grows rapidly under conditions of higher humidity. This leads to cracking and splitting of the fruit. The damaged fruit becomes susceptible to invasion by other spoilage organisms such as yeasts, molds, and 20 bacteria. The important point to note here is that Botrytjs mold is the primary invader, setting the stage for invasion by other microbes which by themselves may not be able to penetrate the skin and cause spoilage. The common spoilage organisms associated with the bunch rot include the following: a) Yeasts - various species belonging to the genera Kloeckera, Hansenjaspors candjda, and Torulaspora. b) Molds - species belonging to the genera BotryUs, Pen7"ci77um, Aspergn 7us, RM zopus, and Mucor. c) Bacteria - species belonging to the genera Acetobacter and Gluconobacter. The infection by BotryUs cinerea and subsequent invasion by spoilage organisms (condition known as sour bunch rot, not to be confused with 'noble' rot) causes many undesirable changes in fruit composition. Because of these changes, the fruit is rendered unfit for winemaking. Some of the most important changes in fruit composition include the following: 1) Loss of fruity and varietal aroma. 2) Development of moldy and/or vinegar-like odor. The moldy odor can develop from the infection of fruit by PenjcUUum and Aspergnlus. The vinegar-like aroma results when the fruit is infected with acetic acid bacteria. 3) The mold Botrytjs produces a powerful oxidizing enzyme called Laccase. This enzyme makes the must and wine more susceptible to oxidation. It is more stable in must and wine than the natural oxidizing enzyme tyrosinase. It is relatively resistant to sulfur dioxide and can oxidize a broader range of phenolic compounds. 4) Higher amounts of sulfur binding compounds are formed in rotten must. Because of this, higher amounts of sulfur dioxide are needed to obtain protection against microbial spoilage and oxidation. 5) Because of the several undesirable changes in fruit composition, rotten fruit should never be used for making wine. Only sound and ripe fruit should be accepted for high quality wine. 2. Yeast Rehydration and Must Inoculation The natural flora of grapes include molds, yeasts, and bacteria. Among these yeasts are important fermentative organisms. At the time of harvest many strains of yeast are present on the surface of grapes. The common types of yeast found on grapes include Kloeckera apiculata, Candida pulcherrjma, and others belonging to the genera: Torulopsis, Brettanomyces, Rhodotorula, and Pichi a. Many of these wild yeasts proliferate during the earlier stages of a natural fermentation. As the fermentation progresses, the natural strains of

21 Saccharomyces tend to dominate the fermentation. Some of these wild yeasts are poor fermenters and can produce undesirable by-products, such as hydrogen sulfide (H 2S) and acetic acid. Therefore, sound fermentation by natural yeasts cannot be reliably predicted. For this reason, use of pure culture yeast has become the widely accepted commercial practice. Using selected pure culture yeast ensures a rapid onset and completion of the fermentation, with low levels of undesirable by-products. When the must is inoculated with a pure culture strain, it is assumed that it will overwhelm the natural indigenous yeast and dominate the fermentation. However, some studies suggest that this may not always be true. For example, Heard and Fleet (1985) found that in a must inoculated with Saccharomyces cerevisiae, the activity of the K7oeckera and Candida species was not suppressed in earlier stages of fermentation and consequently these non­ Saccharomyces yeasts contributed to the fermentation. It is not enough just to inoculate the must with pure yeast to minimize the participation by wild yeast in a fermentation. It is essential to inoculate with a vigorous starter culture to ensure rapid and complete dominance by the desired strain. To achieve this objective and obtain a complete and predictable fermentation, proper rehydration and inoculation is essential. Rehydration of Yeast: Commercial active dry wine yeast is produced under special propagation conditions. The cells contain optimum nutrient content to conduct a rapid and efficient fermentation. During the process of drying, the cells lose 70-80% water. The dry yeast can maintain viability (about 90% per year) when stored under a vacuum and in the absence of oxygen. When yeast cells are rehydrated they quickly absorb water. In the case of improper rehydration, the cells tend to leak the cellular compounds through the cell membrane and consequently become less viable. The cells also clump and are difficult to disperse in water. The temperature at which the cells are rehydrated is critical for maintaining viability. For example, the addition of dried yeast to water at 15°C (59°F) or below has been reported to cause 60% reduction in cell viability. Procedure for Rehydration of Dried Yeast: For proper rehydration, Monk (1986) suggested the following points; 1. The volume of water used for rehydration should be 5 to 10 times the weight of dry yeast. For example, if you use a 2 lb/1000 gal rate, then 2 lb yeast can be rehydrated in 1 1/4 to 2 1/2 gal of water. 2. Rehydrate in warm water at 40-45°C or 104-113°F. 3. Add yeast granules to water not water to yeast. (To avoid clumping and uneven rehydration.) 4. Allow yeast to remain in warm water for 5 to 20 minutes before stirring.

22 5. Do not prolong the rehydration period over 30 minutes as this may reduce cell activity. 6. Do not rehydrate in must. Procedure for Inoculation:

1. The rehydrated yeast should be gradually cooled to about 20°C (68°F) before adding to the must. The difference in temperature between the must (to be inoculated) and the yeast inoculation should not exceed 10°(. This will minimize the cold shock and preserve viability. 2. To initiate a rapid fermentation, the yeast inoculum should contain 5 x 106 viable cells/ml or more. 3. To achieve this cell density, rehydrate yeast at the rate of 25 g/100 liters. (This is about 1 g/gal of must.) 4. Do not add dry yeast directly to the must. 5. Do not use fermenting must to inoculate new must. This may increase contamination by the spoilage organism. Secondly, a dilution of the survival factor will occur, which may cause a stuck fermentation. 3. Wine Aeration and Its Adverse Effect Prolonged contact with air is detrimental to wine quality. Certain wines, such as sherry and madeira, are exposed to air during the course of their production. On the other hand, premium table wines are produced with minimum or limited air exposure. White wines tend to improve when processed under low oxygen conditions. Red wines usually benefit with air exposure up to a certain point, but beyond this critical point, aeration is detrimental. How does prolonged air contact impair wine quality? There are two ways in which wine quality is impaired by air exposure over a long period of time: 1) oxidation and 2) spoilage by aerobic microorganisms. Oxidation: Let us first consider oxidation and its effects on wine quality. when a wine is exposed to air, the oxygen from the air is dissolved into the wine. This step is a physical process. The dissolved oxygen reacts with certain phenolic compounds in the wine and causes their oxidation. The oxidation reaction is a chemical reaction. It is catalyzed by the enzyme polyphenol oxidase, but it can also occur without the participation of the enzyme. Oxidation causes a loss of fruity and varietal aroma, browning, and development of aldehydic or nutty flavor. Spoilage by Aerobic Microbes: When a wine is stored in contact with air over a long period, spoilage due to the growth of aerobic microorganisms can occur. Aerobic wine spoilage causing organisms include certain yeasts and acetic acid bacteria.

23 Yeast: Film forming yeasts such as those belonging to genera Pichia often develop on the surface of wines exposed to air. The source of yeast is grapes and/or contaminated processing and storage equipment. The growth of this yeast is often associated with the formation of undesirable compounds such as acetaldehyde and ethyl acetate. These and other undesirable compounds contribute to off odors. Acetic Acid Bacteria: The acetic acid bacteria are known to cause spoilage in wines stored in the presence of air. The bacteria oxidize ethanol and produce acetic acid. Some ethyl acetate is also produced during their growth. These two compounds give the wine a typical vinegar-like aroma. The aroma is very offensive and consequently the wine is undrinkable. The bacteria gain entry into wine from grapes (especially rotten ones) and contaminated cooperage. When the conditions for their growth becomes favorable, they grow and cause wine spoilage. Since the air (oxygen) stimulates their growth, it is important to protect wine from excess air contact.

Winemakers often use sulfur dioxide (S02 ) as an antioxidant and antimicrobial agent to protect wine from the harmful effects of aeration. In addition to S02 , wineries also use inert gases (nitrogen and/or carbon dioxide) to protect their wines from undue air exposure. This approach helps in reducing the amount of S02 needed in wine. Practical Considerations to Minimize Air Exposure: Winemakers should follow those measures which will enable them to minimize excessive aeration of wine during the course of processing. These should include things like keeping the containers full, filling tanks and barrels from the bottom, keeping pumps and hoses leak-free, and exercising caution when pumping cold wine and when agitating, mixing and blending the wine. The measures coupled with judicious use of inert gas will prevent wine from undue aeration and subsequent deterioration. Keeping Wine Containers Full: Not keeping containers full is one of the most important reasons for poor wine quality. It is more common than often realized. One way to deal with this problem is to have containers of various sizes at the winery so that a wine can always be stored in full containers. The other approach is to use a variable capacity wine storage tank. This type of tank is designed so that the top lid can move up and down inside the tank. The rim of the lid is equipped with a food grade, inflatable rubber tube, which is inflated with nitrogen. When inflated, the tub seals the space between tank wall and the rim of the lid. When the tube is deflated, the lid can move freely inside the tank. These tanks are available in stainless steel or fiberglass. They come in different sizes and are very useful in eliminating the problem of ullage space. Checking the Pump for Air Leaks: Another reason for excess aeration of wine during processing is the use of a leaky and defective pump. This is particularly serious if the air leak is on the suction side. One way to check the hose and pump for leaks is to place both the suction and delivery ends in a tub or bucket containing soap solution. Circulate the solution through the hose and pump, and look for small bubbles. The presence of bubbles indicates

24 an air leak. Another way to spot a leak is to connect the delivery end of a hose to a closed valve and the suction hose to the water outlet, then turn the water on. (This will build pressure.) Examine the hose and pump for leaks. Once the leak is spotted, it is important to fix it before the pump and/or hose is used. Danger of Aerating Cold Wine: The solubility of oxygen in wine is greatly influenced by temperature. The lower the wine temperature, the greater the solubility of oxygen. A cold wine such as one racked after cold stabilization will absorb a great amount of oxygen if exposed to air. The oxidation of the wine will become noticeable when the wine warms up. For this reason, great care should be exercised to protect a cold wine from air exposure. 4. Use of Inert Gases Nitrogen and carbon dioxide are the most commonly used inert gases in the wine industry today. In some cases a mixture of these two gases in varying proportions is also used. The use of a particular gas depends on the type of wine and its intended purpose. Nitrogen: Nitrogen is present in the air. The solubility of nitrogen in water at atmospheric pressure and at 20°C is about 19 mg/L. It is about 8 to 9 times less soluble than C0 2 . Due to low solubility, it is often used for sparging wine. Carbon Dioxide: Carbon dioxide is produced naturally during fermentation. It is very soluble and the solubility in water at atmospheric pressure and 20°C is about 1.69 g/L. The gas is heavier than air. Its density at 0°C is 1.52 as compared to the density of air which is about 1.0.

It is important to note that C02 is a normal constituent of still table wine, and almost all finished wines contain some dissolved C02 . The recognition threshold for C02 in wine is about 0.6 g/L. Wine usually contains between 0.4 to 1.0 grams per liter of C02 . The optimum level depends on the style of wine. Dissolved C02 (carbonic acid) gives a hint of tartness and freshness to a wine. It seems to improve palatability and enhance the flavor. In some wines, such as full-bodied reds, higher concentration of CO may accentuate the harsh character. Generally, white wines are producea with higher C02 levels than reds. White Wines: Nitrogen can be used for sparging a white wine to remove dissolved oxygen, but it may also strip C0 2 off below the optimum level and then render the wine less palatable. Wines with less than 0.2 g/L C02 are considered to lack freshness. To overcome the problem of CO? stripping, either co4 or a 1 part nitrogen is recommended. For prevent1ng the air contact w1th wine, flushing is recommended. For preventing the air contact with wine, flushing the empty space or blanketing the ullage with C0 2 is suggested.

25 Red Wines: In handling red wines, nitrogen is the gas of choice for sparging. However, to retain a small amount of dissolved C02 in some reds, a mixture of 2 parts nitrogen and 1 part C02 may be more desirable.

C02 should be used for the purpose of blanketing or flushing air from the empty space (in a tank or other container). However, caution should be exercised since COa is very soluble and a red wine can pick up higher than optimum levels of C02 • The best approach is to try these gases individually or as a mixture to achieve different objectives and develop a plan that best suits your needs. There are two ways in which the inert gases are used: 1) sparging and 2) flushing and blanketing. Sparging: Sparging is done to effectively remove dissolved oxygen (or CO~) from the wine. The process of sparging is based on the application of a sc1entific principle known as Henry's Law, which states that the solubility of a gas in a liquid is proportional to the partial pressure of that gas in the gaseous atmosphere in contact with the liquid. During sparging the inert gas is introduced in the wine in the form of very fine bubbles. When the bubbles are dispersed, a partial pressure develops between the inert gas (N2 or C02) and the dissolved gas (02). The difference in partial pressure causes the dissolved gas (02) to leave the wine. The efficiency of sparging is influenced by many factors, such as bubble size, contact time between the gas and wine, temperature of the wine, gas pressure, and the flow rate of gas in relation to the flow rate of wine. The smaller the bubble size for a given volume of gas, the greater the interface area and the more efficient the stripping of oxygen. The bubble size is determined by the porosity of the sintered element in the sparging unit. Usually a maximum bubble size of about .03 mm diameter is considered acceptable for sparging. As far as the contact time is concerned, the longer the contact time, the more efficient the sparging. Sparging is usually done at a temperature of 59 to 68°F and at a pressure of 1 to 2 atmospheres. The suggested flow rate of the inert gas in relation to the flow rate of wine is in the range of 0.1 v/v to 0.3 v/v. This means a flow rate of 0.1 to 0.3 liters of inert gas per liter of wine. In some situations a higher rate such as 0.3 to 0.8 liter of gas per liter of wine may be required to achieve the desired results. Flushing or Blanketing: Flushing or purging with an inert gas implies displacing the air from an empty vessel, empty bottle, or any other empty but confined space with the inert gas, usually C02 • In the case of blanketing, an attempt is made to maintain a layer of gas over the wine surface. Wineries use various means to achieve a purging, flushing or blanketing operation. For example, some wineries use a gas cylinder and a hose connected to the cylinder and equipped with a valve to control the flow of gas. The gas is allowed to flow into the space from which the air is being displaced. This procedure is often used to top the head space in partially filled tanks, 26 barrels, or other containers. Some wineries bubble the gas through the wine and expect the gas to form a layer or blanket on the top of the wine surface. The amount of gas used is usually estimated. The effectiveness of these procedures are rarely tested and is questionable. In some cases the ullage space in a partially filled container is blanketed with CO~ on a regular basis. It is assumed that C02 being the heavier gas will torm a layer above the wine surface and thus protect the wine from the air (keep oxygen away). In reality this rarely works. C02 does not form a permanent layer, it eventually is uniformly distributed throughout the empty space. It may dilute the oxygen concentration in the space. Unless 02 concentration in the ullage space is tested, the effectiveness of the process cannot be ascertained. Some people use a lighted candle to test oxygen concentration. The lighted candle or a lighter is placed in the blanketed ullage space. If the candle goes out, they conclude that the oxygen concentration is sufficiently low. This kind of test is not valid, and should not be relied upon. The air contains 20.9% 02 by volume. When the 02 concentration in air drops below 16.5% the candle quits burning. The object of flushing or blanketing should be to lower the 02 concentration to 0.5% by volume or lower. This will discourage the growth of aerobic microbes. The 02 concentration should always be checked with an oxygen meter whenever a gas is used to displace the oxygen. Practical Suggestions for Using Inert Gas: Inert gas can be used in those situations where the wine is likely to be aerated. During processing, there are several occasions when the wine faces the danger of oxygen pick up. Some of the important occasions include: 1) wine transfer, 2) bottling, and 3) wine stored with ullage space. Wine Transfer: Whenever a wine is moved from one container to another, it should be protected with an inert gas such as CO~. This can be accomplished by displacing air from both the racking and rece1ving containers. To displace air, the vessels should be purged with 3 to 7 volumes of the gas. It is also helpful to flush the hose and pump with gas. A wine may also be sparged during pumping. This will remove the oxygen already dissolved in the wine. After the wine is pumped, with or without sparging, the oxygen concentration in the wine should be checked. Bottling: The wine is particularly prone to oxidation at the time of bottling. The turbulence of wine with air inside the bottle during the filling operation encourages oxidation. For this reason the bottles should be flushed with C0 2 or nitrogen prior to filling. A wine can also absorb significant amounts of oxygen from the head space in bottles after it is filled. The modern bottling machines are now equipped to purge the bottles with inert gas before and after filling. The goal of bottling should be to reduce oxygen levels to 1 ppm or less. Wine Storage with Ullage Space: Sometimes the wine is not stored in full containers. This permits the prolonged air contact which can cause oxidation and microbial growth. The oxygen pickup from the air space above the wine can be rapid. Peynaud (1981) reported that in a wine kept in contact with air, about 1.5 ml/L of 02 was absorbed in the first hour (surface area of 100 cm2). 27 In 4 hours the upper layer was saturated. To prevent the problem of oxygen pickup, the ullage space should be flushed with inert gas (C0 2 ) and a blanket should be established and maintained to keep oxygen excluded. Blanketing should be accomplished by introducing the gas into the ullage space with a gas diffuser. The gas should be replenished frequently to keep the 0? level in the ullage space to less than 0.5%. The concentration of 02 in w1ne should be about 1 ppm or less. There are several types of systems available on the market that can be installed to deliver the inert gas. These systems usually include a source of gas, gas lines with valves, and pressure regulators connected to the bottom of the wine tanks. The flow rate of gas into the tank is regulated. As the tank is emptied of wine the gas flows into the tank. When the wine is pumped into the tank, the tank pressure rises, the flow of incoming gas stops and the excess gas from the tank is allowed to escape through a pressure relief device.

5. Proper Use of Sulfur Dioxide (50 2)

Use of sulfur dioxide (S02 ) in winemaking is a very old practice. It is used for its antiseptic and antioxidative properties. In recent years the presence of SO in wine has come under greater scrutiny. This is due to the fact that peop~e with asthmatic conditions are considered to have an allergic reaction to sulfites. The amount of S02 in wine is regulated by law, and excess S02 in wine adversely affects wine quality. Because of adverse health effects in people with asthmatic conditions, legal limits, and the reduction in wine quality when used in excess, winemakers should be interested in minimizing the use of S02 in wines.

In order to produce wines with low S02 levels, the winemaker needs to have an understanding of the behavior of S02 in wines. Function of Sulfur Dioxide Sulfur Dioxide as an Antiseptic Aoent: Sulfur dioxide is an effective germicide. The order of effectiveness is reported to be as follows:

Bacteria > Molds > Yeasts

In general yeasts are more tolerant of S02 than bacteria, although yeast strains vary in their ability to tolerate S02 • For example, strongly aerobic strains or the poor fermenting types are more sensitive to S02 than the strong fermenting types. The spoilage causing acetic acid and lactic acid bacteria are sensitive to S02. Among various forms of free S02, the molecular or undissociated form is the most toxic to these microorganisms. Maintaining about 0.8 mg/L molecular S02 is recommended to prevent wine spoilage by the harmful organisms. Sulfur Dioxide as an Antioxidant: Oxidation of must/wine causes browning, loss of fruity aroma, and the formation of oxidized odors. Oxidation can occur either with or without the participation of enzyme.

28 In enzymic oxidation, the enzyme polyphenol oxidase (PPO) catalyzes the reaction between a phenolic compound and the oxygen. This leads to the formation of o-quinones which polymerize and yield dark-colored compounds. Sulfur dioxide prevents oxidation by inhibiting the enzyme and/or reacting with o-quinones and thus inhibiting quinone condensation. The reaction is illustrated in Figure 1.

Figure 1.

OH 0

OH 0 polyphenol oxidase + 1/2 0 2 ...

H..,O L R R + A Phenol A quinone

Grapes infected with the fungus Botrytis cinerea (a mold) contain a powerful oxidizing enzyme called Laccase. This enzyme oxidizes a broader range of phenolic compounds, is more stable in must and wine than PPO, and is relatively resistant to sulfur dioxide. For this reason, moldy and rotten grapes should not be used for winemaking. In the case of non-enzymic browning, oxygen reacts with a phenol, yielding a quinone and another oxidizing compound such as hydrogen peroxide. In a subsequent reaction, hydrogen peroxide oxidizes ethanol to acetaldehyde. The reactions of various forms of free S02 with hydrogen peroxide are shown below:

1. 2. 3.

As the reactions given above indicate, hydrogen peroxide oxidizes S02 to sulfate, thus ethanol is saved from the oxidative effect of hydrogen peroxide.

Forms of Sulfur Dioxide: When S02 is added to the must/wine, a portion of it becomes reversibly bound to certain constituents. The remaining portion which is not bound is termed as "free S02". The sum of free and bound S02 is called "total S0 2 ". Free S0 2 acts as an antioxidant and a germicide and, therefore, is very important to the winemaker.

29 Free S02~ Free S02 in must/wine exists in three forms. They are: 1. molecular SOz., SOz 2. bisulfite, H_::>o3· 3. sulfite, so3- The three species are present in an equilibrium which is influenced by pH. pka 1.8 pka 6.9 H20 + SOz H+ + HS03- H+ SO= molecular S02 bi sulfite sui fi te

The effect of pH on the distribution of various species of free S02 is shown in Table 1 below: Table 1 . Influence of pH on the distribution of three species of free SO,, .

pH % 502 (m) % Hso· 3 % so·· 3 Free SO to obtain &.a ppm molecular SO, 2.9 7.5 92.5 .009 11 3.0 6.1 93.9 .012 13 3.1 4.9 95.1 .015 16 3.2 3.9 96.1 .019 21 3.3 3.1 96.8 .024 26 3.4 2.5 97.5 .030 32 3.5 2.0 98.0 .038 40 3.6 1.6 98.4 .048 50 3.7 1.3 98.7 .061 63 3.8 1.0 98.9 .077 79 3.9 0.8 99.1 .097 99 4.0 0.6 99.2 .122 125 Source: Sm1th (1982)

Under normal situations, 0.8 ppm of molecular S02 is considered adequate to obtain the required protection. It is important to remember that only in the molecular form (undissociated), can free S02 act as an antiseptic agent and be smelled. Usually 0.8 ppm molecular SO is enough to protect a wine from microbial spoilage. The data (Table 1j shows that at lower pH levels, a greater amount of free S02 is present in the molecular form. Therefore, at a relatively low

30 pH, a smaller dose of free S02 is needed to obtain 0.8 ppm molecular S02 . For example, at pH 3.4, it takes 32 ppm from S0 2 to obtain 0.8 ppm molecular S0 2 . However, at pH 3.1, it takes only 16 ppm free S02 to get the same amount (0.8 ppm) of molecular S0 2 . This point has important practical implications. By opting to work with a low pH must/wine, a winemaker can use a smaller dose of free S0 2 and thus reduce the total S02 content in a wine.

Bound S0 2 ~ Several constituents in wine can bind S0 2 . The important S0 2 binding compounds are acetaldehyde, anthocyanins, pyruvic acid, alpha­ ketoglutaric acid, and glucose.

Acetaldehyde, usually the chief S02 compound in wine, has a strong affinity for S02 . The acetaldehyde-bisulfite complex is very stable and dissociates only slightly, in the range of 1 to 3 percent. The binding capacity of acetaldehyde is an important point to consider in understanding the role of S02 in wine. For example, one part acetaldehyde combines with 1.45 parts of ~0 2 . Thus, a wine containing 50 ppm acetaldehyde can have 72 ppm S0 2 bound to the acetaldehyde. Once S0 2 combines with acetaldehyde, it largely stays fixed and serves very little useful function.

Other S02 binding compounds such as alpha-ketoglutaric acid and pyruvic acid have higher dissociation constants than acetaldehyde. Their combination with S02 is not as strong as acetaldehyde's combination. The S02 bound to these compounds is an equilibrium with free SO. If some S02 is lost from the wine, these compounds dissociate and free up sb2 to restore the equilibrium. By lowering the amount of SO binding compounds in wine, one can reduce bound SO~ and maintain sufficienf free S0 2 without unduly increasing the amount ot total S02 . REFERENCES

1. Heard, G. and G.H. Fleet. 1985. Growth of natural yeast flora during the fermentation of inoculated wines. Appl. Environ. Microbial. 50:727-728. 2. Monk, P.R. 1986. Rehydration and propagation of active dry wine yeast. Australian Wine Industry Journal 1(1):3-5. 3. Peynaud, E. 1981. Knowing and making wine. John Wiley and Sons, Inc., New York. p. 248.

4. Smith, C. 1982. Review of basics on sulfur dioxide. Part II. Enology Briefs. 1(2). Cooperative Extension Service, University of California.

31 GROWING VINIFERA IN NORTHEAST OHIO Arnulf Esterer Markko Vineyard Conneaut, OH INTRODUCTION Vinifera grapes grow the same as any other grapevine--no secrets. But, winter injury exists as the major problem. If growers think the winter-injury problem has been conquered, think again. In 11 out of the last 30 years the winter lows have dipped below -8°F (Fig. 1), the temperature at which bud damage of about 50% occurs. The title refers to Vitis vinifera, specifically meaning the traditional wine varieties like Chardonnay, Riesling, Cabernet Sauvignon, Pinot Noir, and Pinot Gris. The Lake Erie region should replace northeast Ohio in the title. This includes parts of New York, Pennsylvania and Ohio which lie along the ban, five to 20 miles wide, of this great lake's shore. Lake Erie moderates the climate as only a very large body of water can. Finally, success depends on people, their knowledge, interest and judgment. Winegrowers must search for improved varieties and cultural practices. The following covers the priorities for survival. ESTABLISHING A VINEYARD Survival depends first of all on a good site, get the best. The best is none too good. A view of Lake Erie is almost essential. This equates to a relation between elevation and distance from the lake. Look for moderate slope and topography which will give air and water drainage. Take soil samples. Look for structure which allows deep rooting and reasonable water percolation. Fertility should not be high. Avoid major site modifications. Good plans will take advantage of contours. Before planting, do minor grading to improve surface drainage. Lay drain tile for wet spots and problem areas. Deep plow old vineyard sites and remove old roots, this may not be necessary on all sites. Deep plowing also may improve the rooting zone depth and structure with top soil and also helps early weed control. Clearing of trees around the planting may improve air movement and sun exposure. Other site modification items to consider are wind machines, irrigation, and heaters. These effect the vineyard microclimate and can be helpful with minor frost problems (Fig. 2), but not major site defects. For planting and trellising, layout and plan to take advantage of contours for drainage and cultivation. We use nine-foot row width for the tractors and vines five to 7 feet apart. Whether the rows run north-south or east-west seems insignificant here. Consider how you will harvest and manage the leaf canopy. Select good rootstocks and scions. For the best take get good grafts-­ #1's. This means a complete callus, thumb tested, and long rootstock, 12 32 inches. Also, I recommend using a good diversity of rootstocks and scion clones of the cultivar you select. This is for improved wine quality and vine survival. Select propagating wood from surviving vines for winter hardiness. Avoid bad viruses and crown galled trunks. Plant carefully and exactly on spot, lines straight and spacing even. Train trunks straight. This all helps minimize future tractor disease. Water, but do not fertilize. Keep growth moderate for hardy trunks. Let the leaves and foliar analysis indicate the need for nutrition. Undercrop young vines. A small hand sprayer to prevent molds works wonders. Cultivate deeply to eliminate weeds and drive roots down. Mound up in the fall for winter protection and weed control. Train trunks straight up using stakes, rods or string. Straight trunks will prevent later tractor injury and cultivation problems with the grape hoe. VINEYARD MANAGEMENT Generally, good vineyard management is the same for vinifera and non­ vinifera varieties. High priorities should go to practices which enhance winter hardiness. These include a balanced crop and moderate vine vigor, control of weeds and fungal infections. Moderate stressing of the vines may be helpful to enhancing early wood maturity. Proper timing of each practice is important. In pruning, strive for moderate yields. Yield should be consistent and balanced year to year with the vines vigor. Our goal is one gallon per vine per year (13 lbs.). This is normally 40 to 50 buds on 9 x 7 spacing. Before pruning begins and if winter temperatures have dropped below -5°F, make a winter kill study. The study should analyze primary and secondary bud kill, and the extent of injury to canes and trunks. We use five damage classes. Class 1 - up to 70% primary bud kill can be compensated by leaving extra buds and canes when pruning. Minimal cane and trunk injury should heal. Class 2 - between 70 and 90% bud kill. Leave all canes cut to about 10 buds. Look at cane and trunk damage. This is where good wood maturity will be important. Avoid all fertilization and minimize cultivation. Mow for weed control. This is when a large carry-over of nitrogen will overdrive the vines. The resulting bullwood makes control and hardiness difficult the next season. Sucker and trunk renewal buds need careful management, and crown gall problems become more serious. Class 3 to 5 (see table). This is when mounding up over the graft will pay off and provide the basis for suckers and renewal of the vines. Double trunking may be of some help for improved survival. Other pruning practices include cutting out crown gall immediately along with winter kill. Brush cut from vines we drop in the row middle and plow under as mulch. 33 Cultivation for weed control is all mechanical or manual. The mound-up is plowed away in March or as early as pruning is done. This levels the rows for tiers, helps control weeds and leaves the floor packed in case of spring frosts. Under trellis use of the grape and hand hoes and weed-eater keeps weeds down. Row middles are cultivated or mowed as needed. Mound up starts mid-August using the grape hoe. Final two-bottom plow up follows the dormant copper spray after leaf drop in the fall. Good canopy management can improve crop and wood maturity and make spraying more effective. To accomplish this we try to position shoots at pruning and later by combing. We try to remove suckers, do shoot and cluster thinning (Chambourcin only) by hand before bloom. Finally, we hedge one to three times depending on vigor. All this to let more sun and air into the canopy and reduce fungal infections. The spraying program avoids herbicides and insecticides because the benefits of a balance in the ecosystem seems important. Antifungal sprays start with dormant copper before bud break. Sulfur, dithane, bayleton and benelate are all used as needed through bloom. Reliance on foliar feeding seems wise in vinifera to moderate vigor. Maxicrop, a seaweed extract, may help organically and contribute micronutrients. Integrating pest management into all facets of vineyard management makes more sense all the time. RESEARCH AND THE FUTURE Each grape and winegrower needs to do research and share it. The strength of our wine industry depends on growing at least one great wine grape and making at least one great wine. The sooner we find that grape and wine the better. It depends on all of us. To improve winter survival we should make careful variety and clonal selections in combination with rootstock trials. Also, find better cultural practices and notice the little difference. Trials of microclimate modification when temperatures drop below -5°F could make a vital gain in this battle. The Orchard-Rite/Kent State wind machine trial (Fig. 3) needs to be continued. Schmidlin has demonstrated the high probability of success. Especially since one-third of the last 30 years in the Lake Erie region had temperatures going below -8°F. The forecast for 1992-93 is not good. We need to look at all aspects of management and make them work for us. This includes insects, weeds, fungus and even viruses. Some viruses may be beneficial. So to close, for success we need to share both our triumphs and failures to improve winter hardiness and find that special grape for this region. In addition to doing all possible in the vineyard we need to keep good records of our experiments. Sharing them helps us all progress. Our academic and research institutions play a leading and coordinating role for all of us. But, the individual growers together contribute the majority of new ideas for basic research, and we need to keep that up.

34 8 -14

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60 65 75 Winter 70 = 1969-70

Figure 1. The coldest temperature of the winters 1958-59 to 1988-89 at the National Weather Service. Erie International Airport, Erie, Pennsylvania. The Erie Airport is located about 2 km from Lake Erie.

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38 DAMAGE CLASSIFICATION A.Bud Evaluation - cut with razor 1=All good (live) buds O=Live secondary or tertiary, dead primary X=A 11 dead EXAMPLE: Totals 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 c 1 0 X 0 0 0 X X 0 0 X X X X X 0 X 0 4 0 7 8 M8 1 1 X X l l l l l l l l l 1 l ' l 13 0 2 RIES l l 1 1 l l l l 0 l l l l l l l 14 l 0 1/31/84 l X 0 X 1 X 0 l 0 0 0 l l 0 l 2 6 6 3 X l 1 0 X 0 X X X X X l X 0 l !' 3 4 3 8 X X 0 0 X X X X X 0 X X X X X 5 0 3 12 2.5 41 64 36 B.Cane Evaluation - 5 phloem/cambium cuts about 1" long in each of 4 quadrants near base--one outwards Grade 0 to 5 for damage seen in darkened phloem/cambium C. Cordon and Trunk Evaluation - Same as for cane, but on appropriate wood. Only if cane damage is 4 to 5.

39 Winter Kill Damage Categories V. Part I I I III IV v

Primary Bud -70 70-90 90-100 100 100 Second Bud 5-10 30-50 80-100 100 100 Cane Cambium 1-2 1- 2 4- 5 5 5 Arm Cordon 0 0 1- 2 5 5 Trunk Cambium 0 0 0 0-1 5

Recommended Prune Leave Remove Cut-off Dig-out pruning normal all damaged vine vine, practice adj. shoots arms & above replant count & spurs canes, graft 1/3" dia. leave union save spurs leave suckers ( 1-2 low) suckers, suckers, hope hope

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12 18 24 HOUR

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0 ~----+-----~----~------14 -12 -10 -8 -6 TEMPERATURE. {C) Figure 2. An example of a temperature inversion measured on the 15 m tower at Markka Vineyard. Average hourly wind speed (top) dropped to less than 2 mph after sunset, then increased before midnight. Temperatures from three levels on the tower (middle) show a sharp increase at the lowest level (0.5 m) after the 17:00 hr sunset, while temperature at the upper levels dropped early. By 19:00 hr, the temperature at 0.5 m. height was 3.5°C colder than the temperature at the standard height (1.5 m) and 6.0°C colder than the top of the tower at 15 m. Natural wind flow reduced the inversion by 22:00 hr. The vertical temperature profiles at two times (bottom) show the development of the inversion.

41 JANUARY 28-29, 1988

-6 -() -7 w -8 c: :J -9 f­ ~ a: --10 w c.. -11 :E w -12 f- -13

12 14 16 18 20 22 24 02 04 TIME

Figure 3. An example of cold protection provided by the Orchard-Rite wind machine. The overnight average hourly temperatures (1.5 m height) at the Grape Research Station and at Markko Vineyard are compared. The wind machine at Markko Vineyard was operated for two hours and provided more than 2°C advantage by reducing the coo 1 i ng rate at vineyard height. Increasing winds brought temperatures up at both stations before dawn. 42 VI. Vineyard Management Schedule January -Pruning - Brush to row middle cut rootstock & scion wood. February -Prune - brush to mid-row -Take bud samples to adjust for damage--keep records. March -Prune - brush to mid-row -Plow away in pruned rows. Bury brush & level for tying -Make bench grafts -Repair trellis April -Prune - finish by May 1 -Repair trellis -Tie vines - arms and trunks -Dormant copper spray May -Early fungal spray - 1/2", 4", 10" -Hoe away under trellis - first -Cultivate middles - disc June -Pre-bloom & bloom - spray -Hoe away final - hand-hoe -Cultivate middles -Mulch July -Hedge canopy early - comb -Pull leaves around fruit -Post-bloom cover spray -Check berry moth traps - time -Foliar sample and analyses -Cultivate/mow under trellis & middle August -Last sprays -Hedge/comb as needed -Hoe-up under trellis by August 15 -Mow or cultivate middles -Sample berries for maturity September -Sample berries -Mow row middles -Prepare for harvest October -Harvest -Keep records November -Dormant copper spray -Two-bottom plow-up to vines December -Cut rootstock & scion wood -Start pruning, if necessary

43 TRENDS IN WINE GRAPE PRODUCTION IN THE FINGER LAKES REGION David V. Peterson Area Extension Specialist Finger Lakes Grape Program Penn Van, New York 14527 INTRODUCTION Many of the recent developments in grape production in the Finger Lakes have been driven by economic considerations. Acreage changes and shifts in variety emphasis, increased use of mechanized pruning and increased use of Roundup for managing row middles are three developments that I think are among the more significant changes over the past 5 years or so. Since these changes also impact Ohio, or could be adapted in Ohio, I thought that they would be appropriate for this presentation. ACREAGE AND VARIETY CHANGES Total grape acreage in 1990 in New York was estimated at 32,846, down from 38,226 in 1985. In the Finger Lakes, acreage decreased from 14,187 in 1985 to 10,647 in 1990. In spite of the loss in acreage, total statewide and total Finger Lakes production was greater in 1990 than in 1985. This is especially encouraging since 1990 was considered an "off crop" year. Growers have apparently found ways to increase their yields and much of the acreage removed was likely some of the least productive. Concord remains the most widely grown variety in the Finger Lakes and in the stat (Table 1). Catawba, Aurore, Niagara, and Delaware continue to be important varieties in the region. Chardonnay has been increasing in acreage and now ranks 7th in the Finger Lakes and 5th in the state. Vinifera continues to increase slowly in acreage and Concord and Niagara have also been planted in modest amounts in the past couple of years. Sagging demands for basically all native American varieties during the mid-1980's resulted in large pullouts, especially Concord (Table 2). Strength in the juice markets has increased demand for Concord and Niagara, and planting these varieties is once again occurring. Much of this new acreage is with grafted vines (especially on replant sites), as growers look for ways to increase yields. Demand for other American varieties continues to sag. Delaware and Dutchess, once prized for champagne production, are now being replaced in the wineries by hybrid and vinifera varieties. Low prices and lower yields than for most other American varieties have made the economics of growing these varieties questionable at best. Catawba, though also declining in acreage, has survived this period somewhat better than Delaware and Dutchess because of its higher yields. Red hybrids, like the native American varieties, hit lows in demand during the 1980's, and acreage decline correspondingly (Table 3). DeChaunac experienced the largest acreage reduction, fueled not only by low demand, but also widespread occurrence of tomato ringspot virus. Acreage of red hybrids 44 has now declined to the point where wineries are not able to get enough, and prices have generally increased over the past two years. Demand is expected to continue to increase as a result of the 60 Minutes report on the "French Paradox", which sent red wine sales soaring immediately after it was broadcast. Wineries have found that consumers are not always willing to spend $10 plus on vinifera reds and that a red table wine in the $5 to $7 price range is a necessary product. This is where the red hybrids have come into the picture. The question has been which red hybrid to plant. Of the varieties currently in production, Baco, Chancellor, Chelois and Foch have been the more desirable ones. Modest new plantings of Chambourcin have also occurred. There is increasing interest in several new red selections in the breeding program at Geneva, and it appears some of these may be the best option for the future. While white hybrids were still increasing in demand in the early 1980's, this has reversed and several of these varieties have found difficult marketing problems in more recent years (Table 4). Hardest hit has been Aurore, which has been phased out of nearly all the smaller premium wineries and has been used less by the bulk producers as well. Wine quality is considered well below the other white hybrids and demand, prices and acreage are expected to continue to decrease. Seyval has also not fared well in recent years, as higher production costs associated with crop control and bunch rot problems have increased economic problems with this variety. Cayuga White and Vidal blanc, both generally quite productive and with relatively few cultural problems have been used increasingly in many wineries. Many winemakers have also favored these varieties, as compared to Seyval and Aurore. Vignoles exists primarily in winery-owned vineyards and is generally produced in limited quantities as a high end sweet dessert wine. While this market is expected to remain stable, the lower yields usually associated with this variety make any increases in demand unlikely. Vinifera, once considered a novelty in the Finger Lakes, is now widely grown throughout the region (Table 5). Chardonnay and Riesling are produced by nearly every winery in the state. Since 1990, red varieties such as Pinot Nair, Cabernet Sauvignon, Cabernet franc, and Merlot are the primary new plantings, although interest in Gewurztraminer seems to be increasing as well.

45 Table 1. Finger Lakes and total New York acreage of the 20 most planted varieties in the Finger Lakes. Finger Total Variety Lakes NY

Concord 3,250 21,006 Catawba 1,501 2,065 Aurore 1,222 1,389 Niagara 774 2,055 Delaware 556 841 Elvira 404 466 Chardonnay 375 983 Baco Noir 332 348 DeChaunac 325 353 Riesling 256 404 Seyval 235 441 Cayuga White 176 192 Vidal 256 119 152 Ventura 92 113 Rougeon 86 98 Pinot Noir 81 196 Colobel 79 85 Vignoles 74 87 Dutchess 73 131 Marechal Foch 48 79

Table 2. Acreage changes of Native American varieties in the Finger Lakes from 1980-1990. Variety 1980 1990

Concord 5,299 3,250 Catawba 2,459 1,501 Niagara 736 774 Delaware 1,222 556 Elvira 499 404 Dutchess 182 131 Moore's Diamond 79 48 Isabella 40 32

46 Table 3. Acreage changes of red hybrid varieties in the Finger Lakes from 1980-1990. Variety 1980 1990

Baco Noir 518 332 DeChaunac 642 325 Rougeon 236 86 Colobel 58 79 Marechal Foch 90 48 Rosette 113 28 Chancellor 18 25 Chelois 32 20 Cascade 57 21

Table 4. Acreage changes of white hybrid varieties in the Finger Lakes from 1980-1990. Variety 1980 1990

Aurore 1,585 1,222 Seyval 172 235 Cayuga White 74 176 Vidal 256 75 119 Ventura 7 92 Vignoles 51 74

Table 5. Acreage changes in V. vinifera varieties in the Finger Lakes from 1980-1990. Variety 1980 1990

Chardonnay 125 375 White Riesling 123 256 Pinot noir 7 81 Gewurztraminer 16 22 Cabernet franc ? 20 Cabernet Sauvignon 7 15 Merlot 7 12

47 MECHANIZED PRUNING Once thought of as a practice that would result in the gradual death of a vineyard, research and commercial experience have now shown mechanized pruning to be a viable, sustainable and sometimes economically necessary practice in many vineyards. While this topic could be the basis of an article itself (or even an entire conference), I will provide just a brief overview of some considerations here. Most mechanical pruning machines for grapevines consist of a basic cutter bar type of apparatus that makes a side cut, and sometimes a top cut or undercut. Vines trained to virtually all types of training systems have been mechanically pruned, although high cordon (Hudson River Umbrella) generally seems to be the best suited. Growers must recognize that since the pruning is not very selective, quality of the wood retained will tend to be lower than if one were hand pruning. As a result, a lower percent budbreak should be expected and the productivity of those buds is also possibly lower. Therefore, the goal should be to retain a higher bud number than you would by hand pruning. Hand followup is an important part of the mechanized pruning program, where vines should be divided and all low hanging and some other excess brush should be removed. Even with hand followup, most growers have found that they can reduce their overall pruning costs by 50% or more. One of the striking features about a mechanically pruned vineyard is the difference in appearance. More old wood and dead wood is retained when pruning and the nice neatly trimmed look of a hand pruned vine must be forgotten. With more buds generally being retained at pruning, leaf area is greatly increased early in the season and the trellis will appear much more filled prior to bloom. Total cluster number per vine is greatly increased, but the number of berries per cluster is reduced. Shoot length is also reduced. The canopy appears much thicker, but most of the fruit is borne on the outer edges of the canopy. Fruit quality is not necessarily reduced in mechanically pruned vineyards. Soluble solids are often lower than in hand pruned vineyards, but crop loads are generally higher. Crop load can be adjusted by the amount of hand followup and by thinning during the growing season (also mechanizable). With tight cluster rot-prone varieties, there may even be an improvement in quality since the fruit is borne on looser clusters that are less likely to rot. Before closing on this subject, I would like to add a few words of caution to those who adapt mechanized pruning. Some sites and varieties will respond better than others. The best sites are likely to be those that are the most successful, whether pruning mechanically or by hand. Concord, Niagara and Cayuga White have responded well to mechanized pruning, while Delaware has been less successful. Vineyards with small vine size generally have not adapted well, as they are very prone to overcropping. Mechanically pruned vineyards require greater management nutritionally and with pest control. With the higher crop loads, nutritional demands are higher, so routine petiole sampling will become even more critical. Weed control and row middle management become even more important as means of insuring the best health of 48 the vine. Retaining old wood can also retain disease inoculum, and pressure from phomopsis cane and leaf spot and black rot are known to increase in mechanically pruned vineyards. The greatest danger of overcrop will occur in the conversion year, as the quality of the buds retained is likely to be higher than in subsequent years. Mechanized pruning can be an excellent means of reducing labor expenses in a vineyard. Yields may actually be increased and the practice is sustainable over the long haul. Hand followup and possibly fruit thinning is necessary to regulate the crop and improve quality. Mechanized pruning is now widely used in the Finger Lakes and in western New York, with as much as 50% or more of some of the most widely grown varieties converted. ROUNDUP FOR ROW MIDDLE MANAGEMENT The following is reprinted from an article that I wrote in the Finger Lakes Vineyard Notes Newsletter, 1991, #5. Roundup applications to vineyards have become a practical, cost effective, and common approach to controlling weeds in row middles in the Finger Lakes. When properly times, one application can take the place of numerous passes that would be required for cultivation or mowing. The erosion hazard is also greatly reduced as compared to cultivation, and competition for water and nutrients is less than with a permanent sod cover. The savings in time and wear and tear on equipment and the benefit to the vines makes it easy to understand why this practice has become so popular. Proper timing depends on a number of factors including stage of vine development, stage of weed development, type of weeds present, and weather conditions. Stage of vine development is important since Roundup cannot legally be applied past the end of grape bloom. The material must be absorbed by mature weed leaves to obtain maximum effectiveness, which explains why some growers have been frustrated with the level of control they got when the application was made too early. The exception is with perennial grasses (quackgrass, orchardgrass) or some winter annuals which have green mature leaves very early in the spring. Since most vineyards are faced with pressure from a large number of different weed species, however, it is generally advisable to wait until early to mid-June (although unseasonably warm temperatures in mid-May may advance the ideal time slightly) to obtain maximum effectiveness and to avoid excessive regrowth. If existing weed growth is much greater than 6 inches tall, mowing prior to Roundup application may be desirable. Weather at the time of application should also be considered. The material should not be applied if rain is predicted within 6 hours of application, if heavy dew is present on the leaves, or if the wind speed is greater than 5 mph. Roundup also works more slowly and may be less effective on weeds stressed by drought, or excessive heat or cold. A low water volume approach (10 gallons water per sprayed acre surface) has generally been adapted by most growers, although it may be used with up to 40 gallons water per acre. The low water volume concentrate sprays also allow a lower rate of Roundup per acre to be used. The rate of Roundup depends on the weed species to be controlled and the level of control desired. As low as 49 1 quart Roundup per acre in 10 gallons of water provides good control of many weeds and at least partial suppression of most others. Hard to kill perennials (field bindweed, for example) generally require higher rates of Roundup. Factors discussed in the previous paragraph should also be considered in the decision. Addition of a nonionic surfactant will enhance effectiveness. For surfactants containing more than 50% active ingredient, use 2 quarts per 100 gallons spray solution. For surfactants containing less than 50% active ingredient, use 4 quarts per 100 gallons spray solution. The width of the boom and spray pattern depends on the row width and the width of the band sprayed under the trellis. Flat fan or low pressure nozzles arranged to obtain 30-50% spray overlap is desired. Some overlap of the under the trellis spray band is also recommended.

50 .. '\ t .. )

., ., ,. TAKE ANOTHER LOOK AT JUICE CLARIFICATION

'. f. [ J.F. Gallander, R.Riesen, and J.F. Stetson Department of Horticulture The Ohio State University/OARDC Wooster, OH 44691 Juice clarification prior to fermentation is an important aspect in producing high quality white table wines (4,6,10). Singleton et al. (7) described the wines from clarified juice as being fresh, clean, delicate, and fruity. Their research also found that wines made from turbid juice were described as being harsh which was related to the high bitterness and astringent ratings. Other research has indicated that juice clarification is beneficial in removing pesticide residues (8) and undesirable microorganisms (10) and prevention of H2S formation (7). In addition, Crowell and Guymon (2) and Groat and Ough (3) reported that an increase in juice solids caused a higher formation of higher alcohols. These findings were in agreement with the Ohio studies by Liu et ~ (6). Wagener and Wagener (9) found that higher values of higher alcohols in white wines were detrimental to wine quality. Also, the formation of higher alcohols in wines was found to be related to the particle size of the juices. Klingshirn et al. (5) reported that the greatest amounts of higher alcohols were obtained from wines fermented in the presence of the largest particles. In order to obtain clarified juices prior to alcoholic fermentation, several methods may be used to remove the insoluble solids. These methods include settling, filtration or centrifugation. In general, settling juice is the most common method of clarification. This method is preferred, especially among the small wineries because the high cost of clarifying by filtration and centrification. For settling, it is recommended that the juice be cooled to approximately 55°F for at least 12 hours with a satisfactory level of sulfur dioxide, about 50 mg/L. Although these conditions are often used by the winemaker, adequate clarification may not be achieved for some juices. The degree of clarification by settling is influenced by several factors including grape maturity, season, fruit condition, variety and certain vinification procedures. In order to ensure well-clarified juice in less time, some winemakers are using pectic enzymes or bentonite. The use of these fining agents also offers the winemakers the advantage of using less tank space during the peak of the crushing season. One disadvantage of settling is the high percentage of lees obtained, but the use of enzymes tend to reduce this percentage. Although clarified juice produces better quality white wines, highly clarified musts may delay the alcoholic fermentation. Studies by Groat and Ough (3) indicated that slower yeast fermentations were found in juices with solids below 0.5 percent (v/v). The purpose of this study was to investigate the effect of treating juice with various clarifying agents on the quality of white wines. There appears to be a lack of information demonstrating the effect of juice clarification by the use of pectic enzymes and other agents on the quality of white wines.

51 MATERIALS AND METHODS In 1991, Seyval and White Riesling grapes were harvested at peak maturity and were immediately destemmed, crushed, and sulfited with 50 mg/L sulfur dioxide. After pressing, the White Riesling juice was ameliorated with sucrose to 20° Brix, while the Seyval juice (21° Brix) was not ameliorated with sugar. The juice from each variety was divided into several lots and each lot was triplicated. For Seyval, the clarification treatments included: 1) control lot--unclarified juice; 2) naturally settled lot--juice was treated by naturally settling at 18°C for 12 hours; 3) enzyme-treated lot--juice was treated with D5L Rohapect at a rate of 0.02 ml/L and settled at 18°C for 12 hours; 4) bentonite-treatment lot--juice was treated with bentonite at a rate of 250 mg/L and settled at 18°C for 12 hours; 5) enzyme/bentonite-treated lot­ -juice was treated with D5L. Rohapect at a rate of 0.02 ml/L, settled at 18°C for 12 hours, and the clarified juice treated with bentonite at a rate of 250 mg/L. For White Riesling, the clarification treatments included: 1) control lot--juice was treated by naturally settling at 18°C for 12 hours; 2) enzyme­ treated lot--juice was treated with D5L Rohapect at a rate of 0.02 mg/L and settled at 18°C for 12 hours; 3) enzyme/bentonite-treated lot--juice was treated with D5L Rohapect at a rate of 0.02 ml/L, settled at 18°C for 12 hours, and the clarified juice treated with bentonite at a rate of 750 mg/L. All clarified juice lots were racked (15L) into five-gallon glass carboys which were equipped with water seals. Each lot was fermented to dryness at 17°C with a wine yeast. After alcoholic fermentation, the wines were racked, treated with S02 , and cold-stabilized prior to chemical and sensory analyses. The finished wines were analyzed for pH, titratable acidity (TA), volatile acidity (VA), alcohol, and free S02 content according to Amerine and Ough (1). Also, the wines were evaluated by a taste panel and each wine was served in a coded glass. The taste panel consisted of four judges with considerable wine tasting experience. Panelists were asked to score each wine for aroma and taste on a ten-point hedonic scale, ten being the most acceptable. The wines from each clarification treatment were judged twice and duplicated. RESULTS AND DISCUSSION No differences were found among the wines made from the clarification treatments in their alcohol contents, TA, and pH values (Table 1). However, there were some differences in VA and free S02 contents, but no real patterns were observed with each varietal wine. From a practical point-of-view, the VA and free S02 values were acceptable for commercial white table wines. The results of the sensory evaluation (aroma and taste) indicated that the judges preferred those wines made from juice which was treated with a pectolytic enzyme (Table 2). For Seyval, the wines from unsettled juice were rated lowest by the panelists, and were described as being less fruity with little varietal character. Although settling (natural) improved wine quality, the wines from enzyme-treated juice were judged best in aroma. Similar results were found for the White Riesling wines and the enzyme-treated wines were preferred in both aroma and taste. Although bentonite, used as a clarification agent, tended to improve wine quality over the unsettled and 52 settled (natural) treatments, the wines from the enzyme-treated juices were ranked superior to the bentonite-treated wines. Also, the combination of enzyme and bentonite did not improve the Seyval wine quality when compared to the enzyme-treated wines. In summary, wines from clarified juice were generally preferred in both aroma and taste to those from unsettled juice. Furthermore, these experiments showed that enzyme-treated wines produced a better quality wine than wines from other clarification treatments. The enzyme-treated wines tended to have a clean and fruity aroma with good varietal character. LITERATURE CITED 1. Amerine, M.A. and C.S. Ough. 1980. Wine and must analysis. John Wiley and Sons, NY. 2. Crowell, E.A. and J.F. Guymon. 1963. Influence of aeration and suspended materials on higher alcohols, acetin, and diacetyl during fermentation. Am. J . Enol . Viti c . 14 : 214- 22 . 3. Groat, M. and C.S. Ough. 1978. Effects of insoluble solids added to clarified musts on fermentation rate, wine composition, and wine quality. Am . J . En o1 . Viti c . 29 : 112- 19 . 4. Houtman, A.C. and C.S. DuPlessis. 1981. The effect of juice clarity and several conditions promoting yeast growth on fermentation rate, the production of aroma components and wine quality. S. Afr. J. Enol. Vitic. 2:71-82. 5. Klingshirn, L.M., J.R. Liu and J.F. Gallander. 1987. Higher alcohol formation in wines as related to the particle size profiles of juice i nso 1 ub l e sol ids . Am. J . En o1 . Viti c . 38: 20 7 -1 0 . 6. Liu, J.R., J.F. Gallander and K.L. Wilker. 1987. Effects of juice clarification on the composition and quality of Eastern U.S. table wines. Am. J. Enol. Vitic. 38:147-150. 7. Singleton, V.L., H.A. Sieberhagen, P. deWett and C.J. van Wyk. 1975. Composition and sensory qualities of wines prepared from white grapes from germination with and without grape solids. Am. J. Enol. Vitic. 26:62-9. 8. Troost, G. 1972. Technologie des Weines. 4th Ed. 931 pp. Eugen Ulmer, Stuttgart. 9. Wagener, W.W.D. and G.W.W. Wagener. 1968. The influence of ester and fusel alcohol content upon the quality of dry white wines. S. Afr. J. Agric. Sci. 11:469-76. 10. Williams, J.T., C.S. Ough and H.W. Berg. 1978. White wine composition and quality as influenced by method of must clarification. Am. J. Enol. Vitic. 29:92-6.

53 Table 1. Chemical composition of Seyval and White Riesling wines made from various juice clarification treatments.

1 2 Clarification TA VA Alcohol Free S02 treatment pH (%) (%) (%) (mg/L)

Seyval Unsettled 3.15 0.54 0.058 12.2 42 Settled-natural 3.18 0.54 0.065 12.2 35 Enzyme 3.21 0.55 0.040 12.2 43 Bentonite 3.18 0.53 0.055 12.2 46 Enzyme/bentonite 3.19 0.52 0.038 12.1 41 White Riesling Settled-natural 3.08 0.50 0.068 11.1 34 Enzyme 3.12 0.49 0.070 11.1 33 Bentonite 3.13 0.49 0.071 11.1 27

1Titratable acidity expressed as tartric acid equivalent, grams per 100 ml. 2Volatile acidity expressed as acetic acid, grams per 100 ml.

Table 2. Aroma and taste ratings of Seyval and White Riesling wines made from various juice treatments. Clarification Mean Scores Variety treatments aroma taste

Seyval Unsettled 4.10 5.00 Settled-natural 4.75 5.15 Enzyme 7.00 6.25 Bentonite 5.50 5.75 Enzyme/bentonite 6.57 6.50 White Riesling Settled-natural 4.90 5.15 Enzyme 6.13 5.85 Bentonite 4.25 5.00

1Each attribute was scored on a 10-point hedonic scale, 10 being most acceptable.

54 SMALL THINGS CAN MEAN A LOT: ML STRAINS FOR WINES Roland Riesen Department of Horticulture The Ohio State UniversityjOARDC Wooster, OH 44691

Outline: l. Definition of lactic acid bacteria ' l '. '. ' 2. General occurrence 3. Classification 4. Specific occurrence and growth in wine

5. Influence of LAB on wine composition 6. Benefits of malolactic fermentation 7. Defects associated with malolactic fermentation 8. Summary - control of malolactic fermentation

55 1. Definition of lactic acid bacteria

Definition: "Lactic acid bacteria (LAB) are differentiated from other bacteria by their ability to produce lactic acid from carbohydrates" This definition doesn't refer to the malolactic fermentation (MLF) itself but differentiates the LAB as a group from all other bacteria. All the bacteria performing the MLF in wine belong to the group of LAB, but not all LAB are capable of carrying out the MLF in must/wine.

2. General occurrence of lactic acid bacteria

dairy products cheeses, yogurts fermented vegetables sauerkraut - meats sausages - alcoholic beverages wine, beer The LAB carrying out the MLF in grape must/wine are only a few species selected by their ability to survive the special conditions found in must/wine (pH, alcohol content, TA, etc.) and to convert malic acid to lactic acid (MLF) under these conditions.

3. Classification of lactic acid bacteria

The LAB are divided into 2 families based on their cell morphology. The families are further divided into genera and species (in parenthesis): family: 1) Lactobacillaceae rods genus: - Lactobacillus (various species) family: 2) Streptococcaceae cocci genus: - Leuconostoc (Leuconostoc oenos) - Pediococcus (P. damnosus, P. parvulus, P. pentosaceus) - Streptococcus The only genus not occurring in wine is Streptococcus. The subdivision of genera into species is based on more complex reactions and specific properties such as: ability to ferment selected carbohydrates, ability to grow at specific pH-levels and temperatures, presence of key enzymes, deamination of amino acids, etc.

56 4. Specific occurrence and growth in wine

The bacteria ecology of various natural and artificial habitats associated with the winemaking process can be summarized as follows: habitat bacteria: population, genera

l ) grapes, leaves, so i 1 less than 100 cells/g

2) must 103 - 104 cells/ml Leuconostoc,Pediococcus,Lactobacillus

3) end of alcoholic a few cells/ml fermentation

4) during malolactic 107 - 108 cells/ml fermentation The bacteria population in the must soon after crushing depends largely on the handling of the fruit (S02-addition, skin contact, juice clarification, fermentation technique a.s.o.). The species in the must generally do not multiply and most of them die off. Only at the end of the alcoholic fermentation, after a lag phase the length of which depends on the wine composition, do the surviving cells begin to multiply and reach a cell density which is similar to the yeast population during the alcoholic fermentation. The ecology of LAB in relation to the specific and highly selective must parameters can be summarized as follows: - pH : The pH is the single most important parameter control­ ling the growth of LAB and the course of the MLF. growth maximum of LAB pH 6.5 7.4 growth minimum of LAB 3.2 4.0 The range found in must/wine represents the minimum growth requirements for LAB in general, but varies considerably with the genus, leading to a further selection: growth minimum for various genera: Leuconostoc 3.2 - 3.5 Lactobacillus, Pediococcus > 3.5

57 From this pH-dependance it can be concluded that - because of the generally higher pH - the growth of LAB in red wines is faster than in white wines. temperature: optimum growth 72 - 77 °F {22 - 25 °C) minimum growth 60 °F {15 °C} no growth <50 °F ( <1 0°C} maximum tolerance: >94 °F (>35°C} This temperature-dependance favors, again, the red wines against the white wines because of the generally higher fermentation temperatures.

- S02 : S02 is an unspecific antimicrobial agent and therefore also effective against LAB. Free and bound S02 can inhibit and/or kill LAB even though bound S02 is 5 - 10 times less inhibitory. The inhibitory effect depends strongly on the timing of the S02-addition. The addition of 30ppm S02 at crush does not interfere with a MLF after completion of the alcoholic fermentation whereas the addition of 30ppm S02 to a young wine kills 95% of all LAB immediately and may lead to difficulties conducting an efficient and economic MLF. - Titratable acidity (TA): No effect on neither the growth of LAB nor the MLF. - Phenolic substances: Phenolic substances are potential inhibi­ tors but do not interfere either with the growth of LAB nor with the actual MLF because of the low concen­ trations found in grapes and wine. - competition by yeast: A competition between yeasts and LAB does generally not exist in a must inoculated with a high and viable yeast population {1 - 2 x 106 cells/ml) because the yeast dominate from the onset of the alco­ holic fermentation: They outnumber the LAB by a factor of approximately 1000. In addition they grow faster because they are better adapted to the conditions prevailing in the must and are nutritionally rather unpretentious compared to the bacteria. Also do they produce antagonistic substances to LAB such as S02 • - pre-fermentation juice treatments: Most treatments such as separation of the skins from the juice in white wines, settling, fining, filtration, centrifugation, addition of enzymes reduce the LAB population and the available nutrients and therefore reduce the growth of LAB. -alcohol: Most LAB can tolerate up to (at least) 12-15% alcohol.

58 - sorbic acid: Sorbic acid is no inhibitor to LAB. To the contrary, LAB can use sorbic acid as a carbon source and produce compounds which are the cause of an unrepairable aroma-defect, the "geranium-odor". These highly selective must parameters represent a rather hostile environment for the LAB preventing them from any noticeable growth under normal circumstances. Only after the completion of the alcoholic fermentation do they find conditions enabling their growth. The surviving genera and species, the course of their growth (length of lag phase, growth rate, survival) and the course of the MLF (duration, metabolism) are mainly determined by the pH and the available nutrients. The factors favoring the growth of LAB after or near the completion of the alcoholic fermentation can be summarized as follows: - pH : The higher the pH the better the growth! - nutrients: LAB are nutritionally fastidious organisms, they need a complex organic medium for growth. They require certain preformed compounds such as vitamins (B-complex}, amino acids and other growth factors because they have lost their ability to synthesize them themselves. The requirement for amino acids depends strongly on the species with no obvious pattern for any given family or genus. Generally, under normal circumstances, the young wine after completion of the alcoholic fermentation is still rich enough in nutrients to stimulate the growth of LAB In addition does the yeast produce a microenvironment which is favorable to the growth of LAB: The lysis of dead yeast cells (autolysis) causes the release of nutrients from inside the cells into the wine. This is particularly important because the LAB are quite often found attached to the yeast cell walls and can there­ fore take advantage of the released nutrients directly and immediately. The locally slightly elevated pH and reduced S02-content in the neighborhood of yeast cells also favors the growth of LAB. LAB are microaerophilic to facultatively anaerobic organisms which means that they require low-oxygen con­ ditions to grow. In addition research has shown that their growth is stimulated by the presence of co~. Both conditions are ideally met near the complet1on of the alcoholic fermentation. carbohydrates: Carbohydrates are the main energy and carbon source for the growth of the LAB. But they don't need much: 0.1% or less, which means that even the driest wine has enough residual sugar to support the growth of LAB. Even though they require carbohydrates for growth

59 their affinity to malic acid is greater. After sufficient growth they start the actual MLF, the con­ version of malic to lactic acid. Generally only after the completion of the MLF do they metabolize the remaining carbohydrates which in most cases leads to serious defects. The biological significance of the MLF is not fully understood which is demonstrated by the various, some­ times contradictive "schools of thought". - decreased competition by the yeast near or after the completion of the alcoholic fermentation. These growth-stimulating factors allow the LAB to reach a popula­ tion of 107 - 108 cells/ml and conduct the MLF. In most cases Leuconostoc oenos is the organism of choice. In the conservation phase (see figure 4) the population decreases slowly. Under specific conditions (high pH, low free S02) other genera such as Lactobacilli and Pediococci can grow and cause a more rapid decrease of L.oenos. 5. Influence of LAB on wine composition

- main reaction: Enzymatic conversion of the stronger, dicar­ bonic L-malic acid to the weaker, monocarbo­ nic L-lactic acid, resulting in a decrease in acidity (0.1-0.3%) and an increase in pH (0.1-0.3 units):

OH OH I I COOH - CH2 - CH - COOH --> CH3 - CH - COOH + C02 L-malic acid L-lactic acid decrease in acidity increase in pH

- citric acid: can be metabolized by most LAB (particularly heterofermentative LAB) to lactic acid, acetic acid, C02 , 2,3-butanediol depending on the pH and the species involved. The typical range of citric acid in wine is 0.1 - 0.5 g/1 which does not lead to spoilage by this reaction. Potential defects have to considered if additional citric acid is added or if juices with high natural citric acid

60 content (e.g. from citrus fruits) are dealt with. - gluconic acid: can be metabolized to lactic acid, acetic acid, ethanol, C0 2 . Gluconic acid is produced in higher amounts by acetic acid bacteria and some fungi (botrytis). - tartaric acid: degradation only in spoiled wines - to lactic acid, acetic acid, succinic acid, C02 . - nitrogenous compounds: amino acids: there are significant changes in the amino acid composition depending on the species in­ volved but without trends for the metabolism of specific amino acids (exception: conversion of arginine to ornithine and urea). peptides, proteins: no evidence for proteases or peptidases has been found. - carbohydrates: The ability to metabolize carbohydrates is an integral part of the definition of LAB. The metabolism of glucose is the base for dividing the LAB into 2 groups:

homofermentative LAB : glucose r (D,L}-lactic acid (Lactobacilli, Pediococci)

heterofermentative LAB: glucose r (D,L)-lactic acid + acetic acid (Lactobacilli, Leuconostoc)

As can be seen from this overview of metabolic pathways acetic acid is a frequent by-product which may lead to serious defects.

6. Benefits of malolactic fermentation

- reduction in acidity: Due to the conversion of the stronger, dicarbonic malic acid to the weaker, monocarbonic lactic acid. This conversion is particularly important in cool, wet and short growing seasons which delay and shorten the

61 ripening process of the berries and therefore the natural degradation of malic acid (respiration}, retaining (too) high malic acid levels. - increase in microbiological stability: wines which completed MLF are without doubt more stable in a micro­ biological sense because the main substrate for the LAB, malic acid, is removed. But the wines are by no means absolutely stable or sterile. There are still enough nutrients, particularly carbohydrates, available to support the growth of LAB. As an illustrative example the growth of 107 CFU/ml of Pedio­ coccus has been observed in a dry red wine of pH 3.8 after the completion of the MLF! In addition the completion of the MLF has no influence on the growth of other potential spoilage microorganisms. If any then the in­ creased pH associated with a MLF might even stimulate their growth! - flavor modification/enhancement: The LAB reach cell densi­ ties similar to yeast during the alcoholic fermentation leading to the speculation that the by-products of the MLF - similar to the by-products of the alcoholic fermentation - influence the flavor profile of a wine. Even though quite often descriptive terms such as "buttery, lactic, nutty, yeasty, oaky,sweaty" are mentioned as being related to MLF the exact source of an aroma and flavor component is generally rather difficult to determine. In addition several experiments have shown that the distinction between "ML-wines" and "non-ML-wines" in duo-trio-tests was in many cases not possible even by experienced tasters. The facts which could support the theory of flavor modifi­ cation can be summarized by the changes a wine undergoes during the MLF: increase in volatile acids (particularly acetic acid) increase in d i acetyl (buttery, 1act i c) flavor threshold of diacetyl: lppm or less. A modest increase (l-4ppm) is said to add complexity, a more drastic increase (5-7ppm) is described as distinct butter-like, over­ powering, undesirable and is generally con­ sidered a defect caused by Pediococcus.

62 increase in ethyl acetate (in lower cone: adds complexity, but dis­ tracts from varietal charact. in higher conc:solvent, airplane glue, nail­ polish remover, typical com­ pound of carbonic maceration) decrease in fruity esters (hexyl acetate, 2-phenethyl acetate, 2-ethyl-n-hexanoate, 3-methyl-n­ butyl acetate) increase in ethyllactate (body, mouthfeel) decrease in malic acid: changes the acid structure of a wine and may take away some of the fresh­ ness and life associated with a low pH - high acid wine increase in pH: one perceives the acidity, sweetness and also the flavors different. The type and degree of modification depends largely on the wine composition, the age of the wine and the LAB (genus, species, strain) involved. 7. Defects associated with MLF

-ropiness, sliminess ("la graisse des vins"): Ropy, slimy wines are thick, they pour like oil, silent, there is hardly any C0 2 escaping. In addition to the increased viscosity an elevated VA is characteristic. The ropiness is caused by the formation of polysaccharides from sugars mainly by Pediococcus damnosus. Only minute amounts of sugar are required (0.1 g/1 or less) but increased sugar contents increase the risk. Optimum parameters for the polysaccharide formation are pH 5.5-6.0 and warm temperatures. Once the slime-forming process has started it can be enhanced by other microorga­ nisms which are able to build polysaccharides such as acetic acid bacteria, yeasts and molds. Ropiness is considered a mild defect, easy to correct by aeration and S02-addition, but a poten­ tial serious defect if not treated properly. At this stage the formation of diacetyl has al­ ready started, the wine may taste bland and stale. If not treated the process continues leading to a ... - diacetyl, lactic hint: Due to an increased formation of di­ acetyl. Depending on the amount of diacetyl and other by-products formed the wine is described as "lactic" or "sauerkraut". Refermentation with fresh grape juice reduces the diacetyl content due to its metabolism by yeast to 2,3-butanediol which is a by-product of the alcohol1c fermentation with 63 a high detection threshold. If left on its own the process continues leading to a ... - lactic defect: In addition to diacetyl acetic acid is formed leaving a sweet-sour taste. At this stage the wine is definitely spoiled without cure. The 3 above mentioned defects are related to each other, they are progressive. They can be corrected at the first 2 stages, but a lack of adequate action at the second stage leads to the third stage which is a defect without remedy. - acetic acid spoilage: Formation of acetic acid by heterofer­ mentative LAB through the degradation of carbohy­ drates. Regarding this potential defect dry wines are "safe": Even though there is enough residual sugar present to support the growth of LAB there is not enough to cause spoilage. This is of course not the case in grape juice, sweet reserves or off-dry wines. - lactic acid spoilage: Unproportional increase of lactic acid due to the degradation of carbohydrates by LAB. The acetic acid- and lactic acid spoilage occur only after the completion of the MLF, because the LAB have a greater affinity towards malic acid and therefore convert the remaining carbohy­ drates generally only after the complete conversion of malic acid to lactic acid. - geranium-odor: degradation of sorbic acid by LAB to form 2-ethoxyhexa-3,5-diene, reminiscent of pelargony leaves. The aroma threshold of this ether is 0.1 ppb! - mousiness: formation of acylated tetrahydropyridines from the amino acid lysine and ethanol by some Lacto­ bacillus strains. Other descriptors used to characterize the defect are burnt beans, ammonia, barnyard animals. The aroma threshold in water of the mousy compounds is 1.6 ppb! The defect is unrepairable. - bitterness: the anaerobic degradation of glycerol by some Lactobacilli leads to the formation of the bitter compound acrolein which can react further with polyphenols thus enhancing the bitterness.

64 8. Summary - control of the malolactic fermentation

- pH 3.2 - 3.4 (threshold: 3.5) The pH is the single most dominating factor controlling the growth of LAB and the course of the MLF. A pH of 3.2-3.4 favors the growth of the desirable Leuconostoc oenos whereas the LAB associated with an undesi­ rable impact on wine quality grow only above pH 3.5

- temperature 65 - 70 °F (18 - 21 °C) The higher the temperature the better the growth of LAB and the faster the MLF with a minimum of 60 °F (16 °C) required.

less than 30 ppm free so2 less than 50 ppm total so2

S02 is a universal antimicrobial agent and therefore also effective against LAB. The levels have to be kept low in order to grow LAB and to conduct a MLF.

- nutrients high nutrient content favors the MLF All processes increasing the nutrient con­ tent such as skin contact, extended lees contact benefit the growth of LAB whereas processes decreasing it such as juice or wine filtration, fining, racking off the lees immediately after the completion of the alcoholic fermentation and cold stabiliza­ tion lower the risk of an unwanted MLF.

- population of LAB: high cell counts favor MLF Measures like juice pasteurization or sterile filtration prevent the MLF whereas storage in a barrel used previously for a MLF increases the odds for a successful MLF.

65 DUI AS A PROBLEM AND SOME OF THE ANSWERS Major D.G. Goodman Ohio State Highway Patrol Columbus, OH 43266-0562 Problem Statement The more severe the traffic crash, the greater the chances are that alcohol is involved. Alcohol is a factor in six percent of all property damage traffic crashes and 15 percent of all injury crashes. However, in 1991 alcohol was involved in 36 percent of all rural fatal crashes. While the alcohol percentage rate has been declining over the past several years, it continues to be over-represented in fatal crashes. If we are to have a significant impact on rural traffic deaths, we must make every effort to remove the alcohol/drug impaired driver. As the following chart indicates, Ohio has experienced a decline in total rural alcohol related traffic crashes in the past several years. Total Patrol Patrol Alcohol Investigated DUI Crashes Crashes Arrests 1987 15,831 10,130 31,901 1988 14,943 10,135 33,211 1989 14,309 9,485 29,644 1990 13,893 9,103 29,106 1991 11,447 7,878 31,245 It would appear that the driving under the influence problem in Ohio is on the decline and that is certainly a positive sign. However, the above crash figures remain at an unacceptably high level and driving while under the influence of alcohol and/or drugs of abuse continues to be the #1 contributing factor of rural traffic deaths in Ohio. Removing the drinking driver from our highways should continue to be the number one priority for highway safety enforcement programs, especially if we are to continue the downward trend of rural traffic deaths we are now experiencing. Law enforcement must continue the aggressive efforts that have brought about this decline. Current Activity The Ohio State Highway Patrol has developed a fatal crash reduction program which concentrates on those violations which contribute directly to the crash problem at those locations. Historically, there has been a direct relationship between removal of drinking or drugged driver and the reduction of rural collisions. This method has proven itself to be the best solution to the fatal crash problem. Our division continues to be a leader among police agencies in the apprehension of the DUI driver.

66 During the calendar year 1991, the Ohio State Highway Patrol conducted several sobriety checkpoints at various locations throughout the state with a significant history of alcohol related crashes. Sobriety checkpoints are but another weapon available to us in our effort to rid Ohio's highways of the DUI driver. Even with heavy media coverage and pre-notification as to the location of the checkpoints, one out of every 24 drivers demonstrated signs of impairment and were diverted for further investigation. While these enforcement programs will undoubtedly have a significant effect on the DUI problem in Ohio, training programs also have an indirect effect on the problem. The efficiency and effectiveness of any alcohol enforcement program is greatly enhanced with trained and skilled police officers. Also the efforts of all enforcement officers are made easier by a judicial system that is fully aware of the new methods and detection techniques including Alcohol Gaze Nystagmus that traffic officers are utilizing in their enforcement efforts. The Ohio State Highway Patrol has trained local, state officers and officials in the most up-to-date methods of detecting, apprehending, and prosecuting the alcohol impaired driver. This training, which bears directly on the DUI problem in Ohio, is a proven help in the solution of these problems. Habitual Offenders Program - The Ohio State Highway Patrol began an innovative project designed to target traffic offenders who have been convicted five or more times for driving under the influence of alcohol and who are still continuing to operate vehicles without a valid license. We know of no other similar programs actively operating in the United States. The pilot project began in a limited number of counties and was expanded to all 88 by the first of the year (1992). All told, approximately 1400 hours of time was devoted to the program during 1991 and 62 five-time offenders were taken off the highways. These offenders had been responsible for over 400 DUI convictions. Portable Breath Testing Equipment - For several years, the Ohio State Highway Patrol has tested the use of portable breath testing instruments (PBT). PBT's are hand-held devices that are carried by the road officer. When the officer comes into contact with a suspected DUI driver, he/she requests that the driver blow into the PBT which then displays whether or not the driver is our. The device is not recognized as and cannot take the place of the required chemical test, but it does significantly increase the officer's probably cause for the DUI arrest. It is particularly useful in detecting borderline our drivers and drivers who have a significant tolerance for alcohol. In fact, since the Patrol began using PBT's, our total our arrests have increased despite a drop in the number of DUI related traffic crashes. This is not to say that the PBT is solely responsible for this increase, but we feel that the device has had a definite impact on our officer's ability to detect the DUI driver.

67 Alcohol There are hundreds of alcohols, some have familiar names such as: ethyl, methyl, wood, isopropyl, grain, rubbing, and butyl. When reference is made to drinking, the only alcohol contained in legal commercial beverages is ethyl alcohol (ethanol). All alcohols will cause intoxication, but ethyl is not as toxic (poisonous) as the other alcohols. The physical properties of pure ethyl alcohol are: viscosity - thin; color- colorless (clear); smell - slight odor; taste - irritating burning taste; and a high affinity for moisture. Ethyl alcohol is present in other commercial products as well, such as mouthwashes, cough syrups and food flavoring. How Does Alcohol Get Into The Body 1. Absorbed through the skin? The main effect alcohol has on the skin is to simply clean off the protective was coating (just like isopropyl alcohol does). It can be firmly stated that no measurable blood alcohol concentration can be achieved by absorption through the skin. 2. Inhaled through the lungs? Gases are absorbed into the body via the respiratory system, and experimentally it is possible to achieve intoxication or even death by inspiring alcohol fumes. However, a person cannot get intoxicated by smelling alcohol fumes in a bar. Only an extremely high concentration of fumes (much higher than possible in a bar, brewery, or distillery), in a confined area, with forced breathing (hyper-ventilation) over an extended period of time could intoxication by induced through the lungs. 3. Orally? By process of elimination we have arrived at the means by which a person gets alcohol into his body. Alcoholic Beverages Alcoholic beverages fall into two categories: Nondistilled beverages and Distilled beverages. Nondistilled Beverages Fermented fruit juices (wines) Fermented malt and cereal grain solutions (beers, malt liquor and ales). Nondistilled alcoholic beverages are prepared by fermenting fruit juice. The maximum alcohol concentration obtained is about 14% by volume. If a wine contains more than 14% alcohol (28 proof), it has been fortified (alcohol added usually in the form of brandy). The starch is converted to sugar by 68 enzymes in malt. The sugars are then fermented to alcohol with yeast. Distilled Beverages Brandy, Whiskey, Gin, Vodka, Rum, Tequila Distilled alcoholic beverages are so named because their alcohol content is increased by distillation. If wines are distilled, the resulting product is brandy. If special type beers or other grain solutions are distilled, whiskey is produced. Whiskey is stored in charred white oak barrels to age. Alcohol as a Food Alcohol is not digested like are other foods. It is absorbed unchanged into the blood stream, and is not stored for future use as are carbohydrates. It is oxidized or burned to carbon dioxide and water and in this way provides the body with calories which the body uses. Thus, it must be considered a food. Blood Alcohol Content (BAC) It is the standard of measurement to determine the amount of alcohol in the body. BAC is the percentage of alcohol in the blood, weight by volume, based on the weight of alcohol (in grams) per each 100 milliliters of blood. Normal Alcohol Level (BAC) It was believed for many years that alcohol was a normal constituent of the body. Specific analyses now demonstrate that, if present at all, it is in the concentrations much less than .001% BAC (not measurable). The route of alcohol into the body is: 1. Mouth and throat 2. Stomach and small intestine 3. Liver 4. Heart 5. Lungs 6. Heart 7. Brain and the rest of the body The Mouth: Only a small amount of alcohol will be absorbed through the lining of the mouth. All traces of alcohol will be gone from the mouth within 15 to 20 minutes after the last drink, thus the 20-minute observation period before any breath test in Ohio. The Throat: The alcohol spends very little time in the esophagus; there is no measurable absorption. The Stomach: The stomach is the first place where alcohol is noticeably absorbed (not digested) into the blood. Absorption from the stomach is slow. Approximately 20 to 25% of the alcohol taken in will be absorbed through the 69 lining of the stomach. The rate at which alcohol will be absorbed from the stomach depends on: The contents of the stomach The strength of the drink The type of mix or drink The contents of the stomach, both in quality and quantity, can slow the absorption rate. The food itself will absorb the alcohol (it will eventually be absorbed into the blood). By slowing down absorption, the peak BAC will be lower than on an empty stomach. Some types of foods retard the absorption rate better than others. Foods like spaghetti and bread will absorb alcohol quite well. Greasy or fatty food will resist absorption. Absorption begins within 1 to 2 minutes of the first drink, and will complete by 90 minutes after the last drink. If the stomach was empty, absorption could complete 30 minutes after the last drink. Stomach content is the biggest single factor in determining the rate of absorption. The absorption rate is optimum at 20% alcohol, which is usually the maximum you can expect in a mixed drink at a bar anyway. Higher or lower concentration would slow down absorption. The type of mix or drink also makes a difference. If there is carbonation present, this speeds up absorption, quicker than with natural juices, water, etc. People have a solid base in fact, when they say champagnes (sparkling wines) go to their heads quickly. The Small Intestines: Absorption from the small intestine is rapid, with about 70 to 75% of the alcohol taken in being absorbed through the first 7 to 9 inches of the small intestine. Alcohol is readily absorbed from the small intestine, with nothing apparently affecting the absorption rate as was possible in the stomach. The Liver: The liver provides the body's mechanism for changing alcohol into useful chemicals. Unlike other foods, the rate at which alcohol is oxidized does not depend on the energy used by the body, but rather on the amount of working liver. The working size of the liver, in proportion to the body, is much the same for all people. Therefore, the proportion of alcohol metabolized in the liver each hour is basically the same for everyone. The rate will be the same during rest or exercise, asleep or awake. Approximately 90% of the alcohol will be oxidized by the liver at the rate of .015% BAC per hour. The Heart: Alcohol has an effect that dilates the blood vessels. The symptoms that demonstrate this effect are, blood-shot eyes, flushed face, and general warm feelings. The final result of this effect is an extra load on the heart to pump more blood. However, even in gross intoxication the normal healthy heart should not have any problems handling this extra load. The Lungs: The lungs aerate the blood and will eliminate a certain amount of alcohol vapor from the blood, giving the drinker alcohol breath. The Heart: The blood from the lungs returns to the heart and is distributed to the rest of the body. 70 The Brain: While the exact reason for the effects of alcohol are not clearly understood, these effects are well know and have been extensively researched. Alcohol is a central nervous system depressant at all dosages. Although is appears to stimulate when used moderately, actually alcohol has a depressing effect on a persons' inhibitions. The brain can be likened to a computer that tells the other parts of the body how and when to function. As the alcohol slowly depresses the nervous system, everything slows down, becomes disorganized and will eventually result in the total crash of the system. The highest functions, such as judgement and self-control, will be affected first, vision problems, loss of muscular control of the voluntary muscles (slurred speech) next, and finally the involuntary muscles are affected. Involuntary muscles control breathing and the heart.

71 Effects of Alcohol at Different BAC Levels BAC Effect .01-.05% Sobriety levels, drinker appears normal .03-.10% More sociable, talkative, increased self-confidence, decreased ambition, shows loss of attention, judgement, intellect, and control over himself. . 04%+ Increased accident involvement . .05-.06% Motor skills are impaired, less tense feelings are accompanied by loss of perception, senses are dulled, fine motor coordinations are lost, and instinct dominates reason. .06%+ The time to adjust from near to far vision may be increased from .1 to .2 of a second. .08%+ The probability of an accident rises sharply. Drivers have more severe accidents, more single vehicle accidents, and more expensive accidents than sober drivers. .08-.10% Poor muscle control, slurred speech, hands not working well together, legs wobbly, clumsiness, muscles cannot contract as quickly or as forcefully, reaction time is increased, pupils of the eyes dilate, reaction becomes sluggish, glare become bothersome, and the drinker is unable to judge distances properly. . 09-.25% A feeling of excitement occurs, and memory is impaired . .18-.30% Mentally confused, his/her basic reactions are exaggerated, the driver overreacts by laughing, getting irritable, angry or crying for no apparent reason, speech is slurred, the sense of pain is decreased,and dizziness and staggering are more pronounced. .27-.40% Usually unable to stand, walk, or even react to his surroundings, sights become distorted, vomiting may occur, the drinker may fall asleep possibly lapsing into unconsciousness or coma. . 50%+ Coma . . 60%+ Death .

72 i ' ' ' ' \ SENSORY EVALUATION OF SPOILED WINES Murli R. Dharmadhikari State Fruit Experiment Station Southwest Missouri State University Mountain Grove, Missouri INTRODUCTION Learning sensory evaluation skills is important to all the people who produce, market and enjoy wines. When consumers acquire these skills, they become discriminating wine drinkers; and usually buy good quality wines. This in turn forces wine producers to make better products. To a wine producer, developing good sensory evaluation skills is indispensable. It is an important tool for controlling wine quality. A winemaker with well developed sensory skills is more likely to make better wines. Thus, production and consumption of quality wines is encouraged when both the consumer and producer acquire sound sensory evaluation skills. One of the more important aspects of learning to evaluate wine is to learn to recognize wine faults. In today's session, I would like to focus our attention on the attributes of faulty wine, the causes of these defects, and how to prevent them in order to make a better product. This will be followed by the sensory evaluation of spoiled wines. There are several factors that contribute to wine spoilage. The major factors to be discussed today include the following: 1. Yeast spoilage 2. Acetic spoilage 3. Lactic spoilage 4. Development of sulfide aroma 5. Oxidation and browning Yeast Spoilage Yeast spoilage can lead to turbidity, deposition of precipitate, and formation of off-odors. The yeasts used to ferment the must can also cause a refermentation in a bottled wine containing residual sugar. Refermentation causes the wine to become cloudy and gassy, but the flavor is usually not adversely affected. There are several ways to prevent a refermentation in the bottle. These include sorbate addition, sterile filtration and bottling. Wine flavor is adversely affected when a wine is contaminated by film­ forming yeasts. These yeasts require air for their growth and often develop on the surface in wines exposed to air. They usually belong to the genera Pichia, Hansenula and Candida. Their activity leads to the formation of several compounds such as acetaldehyde, acetic acid and ethyl acetate. These compounds impart an oxidized and vinegar-like aroma to the spoiled wine. To prevent wine spoilage by these yeasts, the wine should be protected from air and should be adequately sulfited.

73 Another serious wine spoilage yeast is known as Brettanomyces/Dekkera. This yeast is often found in spoiled red wines. The spoiled wine acquires very unpleasant tastes and odors. The off-odors are often described as burnt beans, sweaty horse blanket, band-aid, metallic and mousy. The development of a "mousy" odor has been attributed to the formation of the compound 2- acetyltetrahydropyridine. It is important to note here that this compound has also been found to be produced by certain lactic acid bacteria. Contrary to film yeasts, Brettanomyces grow throughout the wine. The contaminated wine becomes turbid, gassy, and develops off-odors. To prevent spoilage by this yeast, a winemaker needs to follow very stringent sanitation measures, maintain 0.8 ppm molecular S02 , and sterile filter the wine at bottling. Acetic Spoilage Acetic spoilage is a serious defect in wine. The spoiled wine acquires a sour, pungent and sometimes burning aroma and can have a sour, acrid and bitter aftertaste. Such a wine is often referred to as "vinegar-like". This typical odor occurs due to the formation of acetic acid and ethyl acetate. Of the two compounds, ethyl acetate has lower taste and odor threshold values (160-180 mg/L) and is largely responsible for the spoiled taste and very unpleasant aroma. It should be noted that acetic acid is also produced by commercial wine yeasts, but the amount formed is usually very small. When the wine is spoiled by acetic acid bacteria the concentration of acetic acid can be significantly higher. There is a legal limit on the amount of volatile acidity (expressed as acetic acid) that can be present in wine; however, the spoilage can be noticeable well below the legal limit. The bacteria responsible for causing acetic spoilage belong to two genera: 1) Acetobacter and 2) Gluconobacter. They are aerobic (they need air to grow), they have respiratory metabolisms, and oxidize ethanol to acetic acid. Species of Gluconobacter oxidize ethanol to acetic acid only; whereas species of Acetobacter oxidize ethanol to acetic acid and can finally degrade it to C02 and water. For this ability they are also called over-oxidizers. It should be noted here that the reaction involving conversion of acetic acid to C02 and water is inhibited by the presence of ethanol. The mechanism of acetic acid formation is a two-step process. In the first step, ethanol is oxidized to acetaldehyde (which becomes hydrated) and in the second step the hydrated acetaldehyde is converted to acetic acid and water by the enzyme aldehyde dehydrogenase. What is the source of acetic acid bacteria in wine? And how does it exist during the various stages of vinification? There are two main sources of acetic acid bacteria in wine: 1) grapes (sound or diseased) and 2) contaminated winery equipment and storage containers. The bacteria are naturally present on grapes. In the case of healthy grapes, the population is small, eg. 102 cells/g. At harvest the bacteria gain entry into the winery on the fruit. During alcoholic fermentation the bacterial population declines. If rotten fruit with a large bacterial population is used, significant acetification (increase in VA) of the must can occur during the fermentation. Dirty cellar equipment such as hoses, pumps and contaminated wooden barrels 74 are probably the most important sources of acetic acid bacteria in wine. For this reason, great care should be taken in cleaning and sanitizing equipment and containers before they are used for wine processing and storage. Growth of the bacteria surviving after the alcoholic fermentation will depend on how the wine is handled. Handling and storage of wine in a manner favorable to bacteria growth will likely result in spoilage. Favorable conditions include aeration of wine during transfer, storage in partially filled containers, high pH, warm storage temperature, and inadequate levels of free S02 . To prevent acetic spoilage a winemaker should use clean fruit, protect the wine from air, maintain adequate levels (0.8 ppm molecular) of free S02 and follow sound sanitary procedures. lactic Spoilage Another wine spoilage organism that merits our attention is lactic acid bacteria (LAB). These organisms are involved in the production of many fermented foods such as sausage, pickles, sauerkraut, olives and yogurt. They are also known to occur in wine. In wine they are responsible for malolactic fermentation (which may or may not be desirable) and in certain situations wine spoilage. The LAB belong to the genera Leuconostoc, Pedjococcus and Lactobacj77us. These organisms are gram positive, catalase negative, cocci, coccobacilli or rods. They are microaerophilic and grow best under reduced oxygen conditions. They grow throughout the wine as opposed to acetic acid bacteria which grow on the wine surface. Based on their metabolic activity, LAB bacteria can be divided into two groups: Group 1: Bacteria capable of decomposing malic acid, sugars, and citric acid, but not tartaric acid and glycerol. These are the bacteria normally involved in malolactic fermentation. In a must with high residual sugar and high pH these organisms can also metabolize sugar and produce several compounds detrimental to wine quality. Group 2: These organisms can utilize tartaric acid and glycerol in addition to malic acid, citric acid and sugars and cause serious spoilage. The nature and type of spoilage caused by LAB largely depends on wine composition and the strains of bacteria present. The wine composition determines the various constituents available to bacteria as substrates and the type of bacteria influences the kind of by-products formed from a given substance. The spoilage caused by lactic acid bacteria is complex and varies considerably. A variety of off-odors are formed and they have been characterized as mousy, geranium-like, butyric or rancid butter, sauerkraut­ like, pickle aroma and cheesy. 75 What is the source of these bacteria? The bacteria are naturally present on grapes and when the grapes are processed they get into the wine. They are also present in the winery and especially in contaminated wooden barrels. At crush their population in the must is small. The population declines during the alcoholic fermentation. This may be due to the competition by yeast and the formation of ethanol and S02 (by yeast). Following the fermentation the population can grow and cause malolactic fermentation. Following a malolactic fermentation the fate and activity of LAB depends on how the wine is handled and stored. It should be noted that MLF causes an increase in pH, and this makes a wine more prone to attack by undesirable types of lactic acid bacteria. There are several factors that favor the growth of lactic acid bacteria. The important factors include high wine pH, inadequate S02 , and warm storage temperatures. To discourage the growth of undesirable lactic acid bacteria, it is important to work with relatively low must pH, adequate S02 , cool storage temperatures and good sanitary practices. Hydrogen Sulfide

Hydrogen sulfide (H2S) has a very unpleasant odor. It smells like rotten eggs. It is one of the most undesirable metabolites of the (yeast) alcoholic fermentation. Sulfur is an essential element for yeast growth. It is present in grape juice as sulfate (S04 ). The sulfate is converted to H2S before it is incorporated into other compounds such as proteins and vitamins. A simplified version of yeast sulfur metabolism was reported by Eschenbruch (1982) to be as fallows:

H2S .. Amino acids, proteins, hydrogen vitamins, and other sulfate sulfide sulfur compounds

It should be emphasized that H2S is an intermediate by-product of yeast sulfur metabolism and thus, it is naturally formed during alcoholic fermentation. It is very volatile and can be detected when present in small quantities.

What is the source of H2S in wine?

There are various sources of H2S in wine. It is important to understand them in order to minimize its formation and consequently the spoilage of wine. Organic Sulfur Compounds: Sulfur containing organic compounds such as amino acids are synthesized as well as decomposed by yeast. HzS is formed during the process of synthesis or breakdown. For example, H~~ is an intermediate by-product in the formation of cysteine and meth1onine. Decomposition of cysteine results in the production of H2S, pyruvate and ammonia. Yeast metabolic activity is, therefore, an important source of H2S 76 formation.

Inorganic Sulfur Compounds: Sulfate (SO~) is the inorganic form of sulfur present in juice. The oxidized forms of sultur (S04 and S02) are reduced by the yeast and are used in the production of various cell constituents. These metabolic pathways involve H2S production. Elemental Sulfur: Elemental sulfur can be readily used by yeast to produce H2S. In fact, this is probably one of the most important sources of H2S in wines. How does elemental sulfur get into wine? There are two important sources of elemental sulfur in wine. First, is the use of sulfur containing fungicides such as lime sulfur. If residual sulfur is present on the grapes at the time of harvest, it can get into the must. For this reason, it is recommended to hold the last sulfur spray application about 35 days before harvest. The second source of elemental sulfur is insufficiently burnt sulfur strips or candles used to sterilize wooden cooperage. To avoid this problem, a small device called a sulfur candle holder should be used to burn the sulfur strips. Yeast Strain: Yeast strains widely differ in their ability to produce H2S. Therefore, a selected pure culture of a low H2S forming strain should be used for conducting the fermentation. Certain strains (including wild ones) can have a metabolic disorder which results in H2S formation. These strains require vitamins such as pantothenic acid and pyridoxine. In the absence of these compounds H~S is produced. For this reason yeast having no metabolic disorders should be chosen for the fermentation. That means that the winemaker should not relay on natural wild yeast for the alcoholic fermentation. Supplementing a must with these vitamins can minimize H2S problems. Yeast autolysis occurs when the wine is left on lees, following the alcoholic fermentation. During this process proteins decompose and certain sulfur containing amino acids can be released. Degradation of these amino acids can produce H2S. It is, therefore, advised that the wine be racked off the lees soon after the fermentation. Juice Composition: Must deficient in assimilable nitrogen have been found to produce H2S. It is claimed that in these musts the extracellular proteases degrade juice proteins which result in H2S formation. In the case of nitrogen deficient musts, the addition of nitrogen such as diammonium phosphate can overcome the problem of H2S production. Metal Contamination: The presence of certain metals such as zinc and copper can cause H2S formation. Since wineries are using equipment made of stainless steel and plastic, metal contamination does not seem to be a major cause. However, when certain copper-based fungicides are used and the copper residue gets into the must, then the changes of H2S formation are greatly 77 increased.

Ways to Prevent H2S in Wine

Prevention of H2S spoilage is easier than the cure. Towards this goal, several measures can be adopted.

1. Select and use low H2S producing yeast strains for the alcoholic fermentation. 2. Use a yeast nutrient, this should include assimilable nitrogen and several essential vitamins.

3. Rack promptly. Autolysis of yeast can lead to H2S formation. 4. Avoid must contamination by elemental sulfur. Contamination of must by elemental sulfur, either from fungicide or dripping of molten sulfur from candles, will almost invariably cause H2S formation.

What Kind of Wine Treatment Would Remove H2S From Wine?

H2S is very volatile and can be removed if the wine is treated soon after H2S is detected. If H2S is not quickly removed, it can form complex sulfur compounds which can be difficult to remove and can permanently impair wine quality. Some of the measures that can be used to remove H2S are as follows:

1. Aeration: Soon after H2S is detected, the wine should be aerated. Carbon dioxide or nitrogen should be used if wine is sparged to avoid oxidation during aeration.

2. Added sulfur dioxide: In some cases S02 addition can reduce H2S aroma; however, it is important to treat wine soon after H2S is detected. 3. Copper treatment: When copper is added to the wine, the cupric ions combine with H2S to form copper sulfide. The insoluble copper sulfide will settle to the bottom and can be removed by filtration. The BATF regulations require that the residual copper content of the wine does not exceed 0.2 ppm. Therefore, after the copper treatment, vintners must get the wine analyzed to assure compliance with this regulation. Usually copper sulfate is used for this treatment. Oxidation and Browning Oxidation of must and wine causes browning, loss of fruity and/or varietal character, and the development of oxidized or aldehydic odors. Phenolic compounds are the primary substrate for oxidative reactions in wine. These reactions can be enzymic, that means catalyzed by an enzyme; or they can occur without the participation of an enzyme. In this case (without an enzyme), they are called chemical oxidation. Generally, must oxidation is enzymic, whereas, oxidation of wine is direct chemical or autoxidation. 78 Enzymic Oxidation: As the name implies, enzymes catalyze enzymic oxidation. Polyphenol or laccase (in the case of botrytis infection) oxidizes phenols in the presence of 02; it oxidizes phenols into quinones. The 0- quinone can polymerize and form dark colored pigments. This second reaction (polymerization) does not involve enzyme participation. Sulfur dioxide inhibits the activity of these enzymes and thus, prevents oxidation. It should be emphasized that the enzyme laccase is fairly resistant to S02 and is also capable of using large number of phenolic compounds as a substrate for oxidation. It is also more stable in wine. Chemical Oxidation: In the case of chemical oxidation, oxygen directly combines with a phenol and produces a quinone plus a strong oxidizing agent such as hydrogen peroxide. In a second (but coupled) reaction, the hydrogen peroxide oxidizes ethyl alcohol to acetaldehyde. Sulfur dioxide can inhibit the formation of acetaldehyde by interacting with hydrogen peroxide, which oxidizes it (S0 2 ) to sulfate (S04 ). How to Prevent Oxidation of Must and Wine There are several measures that can be employed to prevent oxidative spoilage of wine. 1. Use of sound and healthy grapes is important. Rotten grapes contain enzymes that make the must more prone to browning.

2. Adding moderate amounts of S02 to must as well as to wine is essential to prevent oxidation. The amount of added S02 should be based on pH. Another important aspect about S02 is that it declines with time. Therefore, it must be replenished periodically. 3. If the must pH is high (>3.5) it should be lowered by tartaric acid additions prior to the fermentation. High pH wines are more easily oxidized. 4. Minimize the aeration of wine during transfer and storage. Use inert gas to sparge the wine and also sparge the storage containers. The wine containers should always be kept full and if a headspace is allowed, then the oxygen content in the headspace should be reduced to less than 0.5%. SUMMARY Undesirable microbial activity and oxidation can cause serious faults in wine. Adopting sound vinification techniques such as using clean fruit, adjusting must pH, using adequate levels of S02, controlling the fermentation rate, minimizing air exposure to wine, and following stringent cleaning and sanitary procedures would help us avoid these problems. Various faults and their effect on sensory attributes of wine are summarized in the table given on the following page.

79 Wine Fault Sensory Attributes Appearance Aroma Yeast Spoil age cloudy, gassy, oxidized, aldehydic may have sediment ethyl acetate and acetic acid Acetic Spoilage cloudy, gassy, acetic acid, ethyl may have sediment acetate "vinegar-like" or VA odor Lactic Spoilage cloudy, hazy, diacetyl, sauerkraut­ may have sediment like, butyric, rancid butter, geranium-like, pickle aroma, mousy and other off odors Hydrogen sulfide rotten egg, garlic, skunky and other sulfide aromas Oxidation browning aldehydic and oxidized aroma

LITERATURE CITED

1. Eschenbruch. 1982. H~S formation - the continuing problem during winemaking. Fermentat1on Technology, Proceedings of a seminar held 4 October, 1982, Mclaren Vales, South Australia, p. 79.

80 \ .

~' \ GRAPE SPRAY SCHEDULE FOR CONTROLLING DISEASES AND INSECTS IN OHIO \ .. Mike Ellis, Roger Williams and Celeste Welty Departments of Plant Pathology and Entomology The Ohio State UniversityjOARDC Wooster, OH 44691 INTRODUCTION The following spray schedule was taken from Ohio Cooperative Extension Bulletin 506-82, "Ohio Commercial Small Fruit and Grape Spray Guide". These recommendations are revised each year and commercial grape growers should obtain a new copy from the cooperative extension service each year. We decided to print the grape portion of the 1993 bulletin in these proceedings for the convenience of Ohio growers that attend the short course, as well as participants from out­ of-state. These recommendations contain much more information than simply what to spray and when to spray. Growers are encouraged to pay close attention to the "comments" sections of this schedule, as well as the tables for fungicide and insecticide efficacy and varietal susceptibility to diseases. Legal Responsibilities for Pesticide Use Pesticides suggested for use in this publication are registered by the Environmental Protection Agency, Pesticides Regulation Division and are cleared for use as indicated on the individual labels. The legal limitations in the use of these pesticides should be strictly observed to prevent excessive residues in or on harvested fruit. Each grower is held responsible for the residues on fruit from his vineyard and should follow labels carefully and observe cut off dates and rates of application. Some of the pesticides listed may be on the EPA restricted use list. Disclaimer Clause References to products in this publication are not intended to be an endorsement to the exclusion of others which may be similar. Any person using products listed in this publication assumes full responsibility for their use in accordance with current directions of the manufacturer.

81 The rate of materials for use on grape is based on a standard of 200 gallons per acre dilute spray.

Pest/Problem Material per 1 00 gallons Ratejacre Comments

DORMANT (Apply before buds swell)

Anthracnose Lime sulfur solution at 5 gal. 10 gals. This dormant application is aimed at reducing overwintering inoculum on canes.

BUD SWELL (Apply just before buds show green)

European red mite andjor Superior oil (70-second viscosity) Scale insects (if present) at 2 gal. 4 gal.

Flea beetle Sevin 80S at 1.25 lb. 2.51bs. Scout your planting before using an insecticide. Use only when necessary. Climbing cutworms or Sevin 50% WP at 2 lb. 4 lbs.

BUD BREAK TO BLOOM (Begin after 1/2-inch new shoot growth, repeat at 7-14 day intervals according to label instructions and environmental conditions for disease development.)

Black rot Mancozeb 80% WP at 1.5 lb. 31bs. Early sprays for black rot are especially critical where this Phomopsis Cane or disease has been a problem in previous years. and leaf spot Captan 50% WP at 1.5 lb. 31bs. Mancozeb is sold under the trade names Dithane M-45, Manzate Downy mildew 200, and Penncozeb. Always read the label. If black rot is a problem in the vineyard, mancozeb would be the fungicide of choice. Captan is less effective than mancozeb for black rot control. See Table 1. Note: Captan has a 4 day re-entry limitation on grapes.

Powdery mildew Bayleton 50% WP at 1 to 3 oz. 2 to 6 oz. On varieties that are highly susceptible to powdery mildew, a or fungicide for powdery mildew control should be included in these Nova 40% WP at 1.5 to 2.5 oz. 3 to 5 oz. early sprays. Primary infections of powdery mildew can occur or during this period. Refer to Rubigan label for further information Rubigan 1 EC at 3 oz. 6 oz. on recommended rates. or SULFUR-there are many formulations of sulfur labeled for use on Sulfur (see note on rates) grapes. Sulfur is available in dry flowable (OF) and flowable (F) formulations, as well as wettable powder (WP) and dusts (D). The dry flowable and flowable formulation greatly reduce the applicator's exposure as compared to wettable powders and dusts. Use rates are different for different formulations. See the label for specific use rates. Some grape varieties are extremely sensitive to sulfur. See Table 4.

Flea beetles Same as for bud swell spray. Use only when necessary. Climbing cutworm

TEN-INCH SHOOT (When new shoots are about 10 inches long)

Flea beetle larvae Same as for bud swell Flea beetle larvae, redbanded leafroller, and rose chafer may be present anytime between 4- to 10-inch shoot growth and bloom.

Redbanded leafroller Guthion 35% WP at 1-1.41b. or 2.1 to 2.81bs. Rose chafer Guthion 50% WP at .75-1 lb 1.5 to 2 lbs. Guthion 2S at 1.5-2 pt. 3 to 4 pts. or Sevin 50% WP at 2 lb. or 41bs. Sevin 80S at 1.25 lb. 2.51bs. or Penncap-M at 1 qt. plus 2 qts. a sticker and spreader

82 Pest/Problem Material per 100 gallons Ratejacre Comments

European red mite Vendex 4 L at 1/2 to 1 pt. or 1 to 2.5 pt. (if present) Vendex 50 WP at 1/2 to 1 lb. 1 to 2.5 lb. or Kelthane 50WP at 1/2 to 1 lb. 1 to 2.5 lbs. Kelthane 50 has given superior results and will replace Kelthane Kelthane 35 WP at 1 to 1 1/3 lb. 1.5 to 3.5 lb. 35WP in the near future.

---·------PRE~LOOM------(Just before bloom)

Flea beetle larvae Same as for 10-inch shoot spray Rose chafer (if needed) Red-banded leafroller* Grape berry moth*

*NOTE Insects are often a problem in vineyards. The use of pheromone traps for grape berry moth and red banded leafroller will indicate their presence and help determine the need for control.

BLOOM

Black rot Same as pre-bloom If wet weather pers1sts during bloom or if Phomopsis cane & leaf spot the time interval between the pre-bloom and Downy mildew petal fall spray is greater than 7 to 14 days. Powdery mildew a fungicide application during bloom may be necessary.

Botrytis bunch rot Benlate 50% OF at 0.5 to .75 lb. 1 - 1.5 lbs. The following information is from the Benlate and Rovral labels: or Apply BEN LATE at 1 to 1.5 lbs. per acre at Rovral 50% WP at .75 to 1 lb. 1.5 - 2 lbs. first bloom (no later than 5% bloom) and repeat 14 days later if severe disease conditions persist. Make an additional application 3 to 4 weeks before harvest or when sugar begins to build; repeat 14 days later if conditions favorable for disease persist, but not within 7 days of harvest. ROVRAL may be applied at 1.5-2.0 lbs. per acre four times: 1. early to midbloom; 2. prior to bunch closing; 3. beginning of fruit ripening; 4. prior to harvest if needed. NOTE: Do not make more than 4 application of ROVRAL per season. A critical spray in vineyards or on varieties (especially French hybrids or Vinifera) where Botrytis bunch rot has been a problem. See Note on New York recommendations for Botrytls bunch rot control under Special Comments on Grape Schedule, page 6.

Grape phylloxera Thiodan 50% WP at 1 lb. or 2 lbs. Apply Thiodan (leaf form) at bloom and repeat 10 to 14 days later. Thiodan 3 EC at 2/3 qt. 1 1/3 qt. Since bees do not pollinate grapes, there is no danger to bees at this time unless they are working on other blooming plants in the area being sprayed. NOTE: Concord, Baco Noir, Chancellor, Colobel and Cascade cultivars may have severe injury if treated with Thiodan Refer to product label.

*Control the root gall form of grape phylloxera by usmg rootstocks denved from Amencan grapes. Native American grapes (Eastern U.S.) are nearly immune to this pest.

PETAL-FALL (Immediately after bloom or 7 to 14 days after last spray)

Black rot* Captan 50% WP at 1.5 lbs. 3 lbs. If Bayleton, Nova. Rubigan. or Sulfur is Downy mildew plus not being used and powdery mildew starts to Ferbam 76% WP at 1.5 lbs. 3 lbs. develop, incorporate one of these fungicides or into the spray program. No more than 3 Mancozeb 80% WP 4 lbs. applications of ferbam may be made per season used alone at 2 lbs. on grapes. See label for additional information.

83 Pest/Problem Material per 100 gallons Ratejacre Comments

Black rot* Bayleton 50% WP at 1 to 3 oz. 2 to 6 oz. A maximum of 18 oz. of Bayleton may be Downy mildew or applied per acre per season. A maximum of Powdery mildew Nova 40% WP at 1.5 to 2.5 oz. 3 to 5 oz. of 24 oz. of Nova may be applied per season or per acre. Sulfur (see note on sulfur, pg.1) *For after-infection sprays for plus control of black rot, see note at end of Mancozeb 80% WP at 2 lb. 4 lbs. petal fall schedule. or Captan 50% WP at 1.5 lbs. 3 lbs.

------Grape berry moth Guthion 35% WP at 1-1.41b. or 2.1-2.81b. It is important to monitor for all insect pests after petal-fall. Leaf hopper Guthion 50% WP at .75-1 lb. or 1.5 to 21bs. Pheromone traps offer help in determining the presence of red Grape mealybug Guthion 2 S at 1.5-2 pt. 3-4 pt. banded leafroller and grape berry moth. Berry moth, Rose chafer Grape rootworm or emergence begins late May and June. There may be three Sevin 50% WP at 2 lbs. or 4 lbs. generations per year. Guthion may be mixed with Sevin or Sevin 80 S at 1.25 lbs. 2.5 lbs. methoxychlor for better control of berry moth. or Examining the underside of grape leaves will indicated if leafhoppers Methoxychlor 50% WP at 3 lb. 6 lbs. are present. Penncap-M at 1 qt. 2 qts. Check insecticide labels for information on specific or insects. lmidan 50% WP at 1 lb. 2 lbs. lsomate GBM for grape berry moth only. See comments or under Special Comments on Grape Schedule. Diazinon 50% WP at 1 lb. or 2 lbs. Diazinon AG 500 (4E) at 1/2-1 pt. 1-2 pts. or lsomate GBM 400 ties

Mites Vendex 50% WP at 1/2 to 1 lb. 1 to 2.5 lbs. or Vendex 4 L at 1/2 to 1 pt. 1 to 2.5 pts. or Kelthane 50WP at 1/2 to 1 lb. 1 to 2.5 lbs. Kelthane 35WP at 1 to 1 1/3 lbs. 1.5 to 3.5 lbs.

*Growers that wish to use an after-infection or erradicant spray program for black rot control should use the higher rates of Bayleton (at least 4 oz.jacre), or Nova (4 to 5 oz.). Research has shown that at these rates good control can be obtained if these fungicides are applied within 72 hours (3 days) after the initiation of an infection period.

Bayleton and Nova will not control downy mildew; therefore, they should be applied in combination with mancozeb or captan. The addition of these fungicides will give additional protectant activity against black rot in addition to controlling downy mildew.

Special note: Unless growers are prepared and for equipped to identify black rot infection periods, an curative type program is not recommended. Instead, a good protectant program should be maintained. See Table 2 on leaf wetness duration-temperature combinations necessary for foliar infection of black rot.

FIRST COVER TO VERAISON (berry coloring) (First cover should follow petal fall 7-14 days: Thereafter sprays should be applied every 10-14 days until veraison. If heavy rainfall occurs, the interval between sprays may need to be shortened. Refer to label for application timing and harvest restrictions.)

Black rot Caplan 50% WP at 1.5 lbs. plus 31bs. Sprays for black rot control may be stopped Downy mildew Ferbam 76% WP at 1.5 lbs. 31bs. after berries turn color (reach 6-8% sugar). or No more than 3 applications of ferbam may be Mancozeb 80% WP used be made per season on grapes. alone **at 2 lbs. 4lbs. **Mancozeb cannot be applied within 66 days of harvest.

Black rot Bayleton 50% WP at 2 to 3 oz. 2 to 6 oz. Fixed copper fungicides should provide Downy mildew or excellent control of downy mildew, but only Powdery mildew Nova 40% WP at 1.5 to 2.5 oz. 3 to 5 oz. moderate to slight control of black rot and or powdery mildew. There are many fixed copper Sulfur (see note on sulfur, under copper fungicides currently labeled for use Bud Break to Bloom) on grapes. The use of copper may result in plus damage to leaves and fruit, especially under Mancozeb 50% WP** at 2 lbs. 4 lbs. cool temperatures and slow drying conditions. or In addition, some varieties are more sensitive, see Table 4. Caplan 50% WP at 2 lbs. 4 lbs.

84 Pest/Problem Material per 100 gallons Ratejacre Comments

Downy mildew Fixed copper (consult the label for use Do Not mix Nova, Bayleton, or Rubigan with copper instructions) fungicides. Read the label.

Gr~ebe7ry~~h------Guthion 35°kWP at ;-:;Alb.--2.1-2.8ib;----See ~om me~o-;;- insect 'Zontr~atPetalF~.------Rose chafer Guthion 50% WP at .75-1 lb. 1.5-2 lbs. Do not use Guthion more than three times in Leafhopper Guthion 2 S at 1.5 to 2 pts. one season. Redbanded leafroller or Do not use Sevin with copper-lime. Grape rootworm Sevin 50% WP at 2 lb. or 4 lbs. Grape mealybug Sevin 80S at 1.25 lb. 2.5 lbs. or Methoxychlor 50% WP at 3 lb. 6 lbs. or Penncap-M at 1 qt. 2 qts. or lmidan 50% WP at 1 lb. 2 lbs. or Oiazinon 50% WP at 1 lb.or 2 lbs. Oiazinon AGSOO (2E) at 1/2-1 pt. 1-2 pts.

Mites Vendex 50% WP at 1/2 to 1 lb. 1 to 2.5 lbs. or Vendex 4 L at 1/2 to 1 pt. 1 to 2.5 pts. or Kelthane 50WP at 1/2 to 1 lb. 1 to 2.5 lbs. Kelthane 35WP at 1 to 1 1/3 lbs. 1.5 to 3.5 lbs.

VERAISON TO HARVEST (Refer to label directions for timing of applications and harvest restrictions.)

Botrytis bunch rot Same as bloom See 'Comments' under bloom spray relative to use of Benlate and Rovral. See comments on New York program for Botrytis bunch rot control under Special Comments on Grape Schedule.

Powdery mildew Bayleton 50% WP at 1 to 3 oz. 2 to 6 oz. A maximum of 18 ounces of BAYLETON may be or applied per acre per season. Nova 40%WP at 1.5 to 2.5 oz. 3 to 5 oz. Do not apple more than 1.5 lbs. Nova per or acre per year. Rubigan 1 EC at 3 fl. oz. 6 fl. oz. Do not apply more than 6 fl. oz. of Rubigan or E.G. per acre per application or more than 19 fl. oz. per season. Sulfur (see note on sulfur, under SULFUR may cause injury to certain grape varieties, such as Concord Bud Break to Bloom) and other Labrusca (American) type grapes. Use with caution.(See Table 4} Do not apply sulfur when temperatures during or immediately after spraying will exceed 85°F. Downy mildew Captan 50% WP at 1.5 to 2 lb. 3 to 4 lbs. If downy mildew is a problem and wet weather or persists at this time period, a fungicide for Fixed copper downy mildew control may be required. Consult (consult label for use instructions) the label for days from last application to harvest.

Black rot As berries reach full size and sugar content starts to increase, they become resistance to infection by the black rot fungus. In general, berries are no longer susceptible to black rot after veraison (6-8% sugar content.)

------Grape berry moth Same as first cover to veratson Continue to monitor for insect and mite pests Grape leafhopper and apply insecticide as needed. Refer to Grape rootworm product label for specific insects, rates and Japanese beetle harvest restrictions. Redbanded leafroller Rose chafer

Mites Same as post-bloom to veraison

RESIDUE COMMENT: Spray residue is unattractive on fresh fruit and difficult to remove.

85 SPECIAL COMMENTS ON GRAPE SCHEDULE 1. GRAPE ROOT BORER

It is generally difficult to evaluate damage from the grape root borer. Injury is most often associated with a slow decline of vineyards, when it can be associated at all. If grape root borer is not a problem, there is no reason to risk destroying the natural control processes (predators, parasites, diseases). Treat with an insecticide only if necessary. If you believe that this insect is affecting your vineyard's performance, you may wish to begin the following program.

Sampling is critical for several reasons: 1) the control program is relatively expensive, 2) use of an insecticide can create, as well as, solve problems.

Immediately After Harvest -sample 10 vinesjacre (but not less than 50 vines); -examine a circular site (3 ft. in diameter) around the base of each plant, concentrating on the inner 1 ft. looking for shed pupal skins of the grape root borer moth. If pupal skins are found beneath S% of the vines examined, apply an insecticide next year.

35 Days Before Harvest If previous year's sample indicates a need to spray, apply Lorsban 4E, following label instructions. Older vines are more likely to be infested. Apply an insecticide as late as the label permits, but before harvest.

2. DOWNY AND POWDERY MILDEWS, Post-Harvest Control

Fungicide applications for the control of downy mildew and powdery mildew are often stopped shortly before harvest. In some years these diseases may cause defoliation well before the onset of cool weather in the fall. Post-harvest early defoliation predisposes the vines to winter injury and reduces fruit set in the following season. Thus, it is important to maintain at least some protection against foliar infections by these fungi.

3. GRAPE BERRY MOTH - Mating disruption strategy

A new use of pheromones is for insect control using the strategy of mating disruption; this expands the use of sex-attractant pheromones beyond their traditional role in insect monitoring. The pheromone is imbedded in 8-inch long plastic twist ties. The atmosphere of the vineyard is saturated with the scent of the pheromone by attaching twist-ties to vines, with 200-400 twist-ties per acre. The pheromone confuses the male moths so that they are unable to locate and mate with females. Females are unaffected by the pheromone and can lay unfertilized eggs, but these eggs are unable to develop. For grape berry moth, the product is called lsomate-GBM, manufactured by Shinetsu Chemical Co. and distributed by Pacific Biocontrol of Davis, California.

4. GRAPE BITTER ROT

Unlike black rot, that does not infect berries once they are past 8% sugar content, bitter rot attacks only mature berries. Both diseases result in black, shriveled (mummified) fruit and some growers have mistaken bitter rot for black rot. A "rule of thumb" is that if a rot resembling black rot develops on mature berries (8% sugar or above) the cause is probably not black rot. This late season rot is likely to be bitter rot. The new systemic fungicides (Nova, Bayleton and Rubigan) are not effective against bitter rot (Table 1). If bitter rot is a problem, pre-harvest applications of Benlate or Caplan may be beneficial. Observe all pre-harvest restrictions.

5. BOTRYTIS BUNCH ROT (New York State recommendations)

Use Rovral SOWP at the rate of 1.S to 2 lb. per acre. Botrytis bunch rot is most commonly a problem on tight-clustered French hybrid and Vitis vinifera cultivars. Proper timing and thorough spray coverage are essential for good control. Make two applications: 1) when the disease is first observed OR when the FIRST berries reach S0 Brix, which ever comes first; and 2) 14 days after the first application. A third spray may be necessary on late varieties (e.g., White Riesling) if the interval between the second spray and harvest is greater than 4 wks. Field experience suggests that effectiveness of the fungicide is reduced following a heavy, prolonged rainfall; if such conditions occur after the last intended spray has been made, an additional application may be necessary. If only one application can be made, wait until the crop AVERAGE is S0 Brix. Direct the spray toward the fruit, and use a minimum of 100 gal/A of water. Include a spreader-sticker, especially at the 1.S lb. rate. NOTE: Growers in Europe and Canada have experienced loss of disease control due to the development of fungicide resistance when more than 3 spraysjyear of Rovral were applied over a period of 3-S yr. It is, therefore, strongly recommended that Rovral use be limited to a maximum of 3 applications/year in New York State to reduce the probability of developing strains of Botrytis that are resistant to this material. NOTE: Removal of leaves around clusters on mid- or low-wire cordon-trained vines before bunch closing has been shown to reduce losses caused by Botrytis in New York vineyards.

86 TABLE 1. EFFECTIVENESS OF FUNGICIDES FOR THE CONTROL OF GRAPE DISEASES

Phomopsis Cane and Black Downy Powdery Botrytis Bitter Fungicide Leaf Spot Rot Mildew Mildew Rot Rot

Bayleton 0 +++ 0 +++ 0 0 Benlate ++ + 0 +++ ++ ++ Cap tan +++ + +++ 0 + ++ Ferbam + +++ + 0 0 ++ Fixed copper and lime + + +++ ++ + + Mancozeb +++ +++ + + + 0 0 ++ Nova 0 +++ 0 +++ 0 0 Rovral 0 0 0 0 +++ 0 Rubigan 0 ++ 0 +++ 0 0 Sulfur + 0 0 +++ 0 0

+ + + =highly effective. + + =moderately effective. + =slightly effective. 0 =not effective. Where Benlate-resistant strains of the powdery mildew and Botrytis fungi have been detected, Benlate will be ineffective and should not be used. Note: The above ratings are intended to provide the reader with an idea of relative effectiveness. They are based on published data andjor field observations from various locations. Ratings could change based on varietal susceptibility and environmental conditions for disease development.

TABLE 2. GRAPE BLACK ROT. Leaf Wetness Duration-Temperature Combinations Necessary for Grape Foliar Infection by Black Rot.

Temperature Minimum Leaf Wetness Duration OF for Light Infection (hr)

50 24 55 12 60 9 65 8 70 7 75 7 80 6 85 9 90 12

Date represent a compilation from several experiments with the cultivars Concord, Catawba, Aurora and Baco Nair.

E7 TABLE 3. Effectiveness of Pesticides Used for the Control of Grape Insects and Mites ~ QJ r- > ..c S...l r- ~ r- QJ r- QJ E s... s... +-> +-> s... s... ~ QJ QJ 0 S...r- QJ r- QJ 0 (.!' s... :::: "'C 0 ~ QJ X +-> QJ +-> 3: 0 c s... co (.!' co QJ o- VI >, +.lQJ +> 0 co ..... VI QJ r-S... s... QJ :;:, +-> VI s... +> +-> s... QJQJ ~ co r- ~ QJ s... +> u ~ QJ +-> +> s... OVI QJ cc QJ >,•r- "'CQJ 4- .,...... ,..... QJ O.QJ E 0 VI a. ~ ~ r- QJ ..c r- QJr- ~ :::: .0 0 r- 0 QJ co VlS... a. LL. VI uu 0..0 "'C r- ..c c 1- LL. ~ > I 0 0 QJ 4- co u s... .,..... s... QJ +.>I.L. ..c QJQJS...QJ QJ- c ~s... QJ .0 QJ +> QJ ~ a. ..c 4- O.O.QJO. ~ a. .0 4- QJ "'C E a. .,..... a. ..c ~ t7l ~ ~ ~..:.;: ~ .,...... ,...... ,..... a. lt:l "'C~ VI ~ :;:, lt:l QJ s... QJ s... s... ~ s... ~ s... QJQJ 0 r- (.!' _J a. s... s... s... s... w t!'t!'Et!' "":) (.!' ~ _J ~ Vl u (.!' LL. (.!' a..

Insecticides Diazinon ++ - ++ ------+++ - 7-18 Dibrom (naled) ------+++ - 1 Guthion (azinphosmethyl) +++ +++ ++ ++ ++ - - +++ ------NTL,10;28* lmidan (phosmet) ++ - ++ -- ++ - ++ ------14 Lannate (methomyl) ++ - ++ ------+ + + - -- 1,14** Lorsban (chlorpyrifos) ------++ 35 Malathion + - ++ -- ++ ------+++ - 3 Marlate (methoxychlor) - - ++ - ++ ++ -- + -- -- - 14 co co Penncap-M (parathion) ++ - +++ - - -- ++ +++ - -- -- 14 Sevin (carbaryl) ++ +++ +++ - +++ +++ - ++ +++ - + + + - - - NTL Thiodan (endosulfan) - - + -- - +++ ------7

Miticides Kelthane (dicofol) ------++ - - - - 7 Vendex (fenbutatinoxide) ------+ + + - - - - 28a

Rating system: + + + =highly effective; + + =moderately effective; + =slightly effective; -=not sufficient data available. *See label restrictions on use. **One day for fresh grapes, 14 days for wine grapes. NTL= no time limitations. Data courtesy of Northeast Pesticide Impact Assessment Program. TABLE 4. Relative disease susceptibility and sulfur, Karathane, and copper sensitivity among grape cultivars

The relative ratings in this chart apply to an average growing season under conditions unusually favorable for disease development Any given variety may be more severely affected.

Susceptible or Sensitive to

Variety BR DM PM Bot Phom Eu CG ALS S[1] K[1] C[2]

Aurore + + + + + + + + + + + +-t-+ ++ ++-+­ No + + Baco Noir + + + + ++ ++ + +-t- +++ ++ No -t-+ ? Cabernet Franc + -t- + ...... + + ? ? ~-+-+ ? No ? Cabernet Sauvignon ++..,... +++ +-++ + +++ +-r+ +++ ? No ? + Canadice +++ + ++ ? ? ++ ++ ? ? ? Cascade + ++ ++ ....-+ ? No ? Catawba ++-r ++...;.._ +;-+ + No No + + Cayuga White ..,...+ + ++ No Chancellor Yes Chardonnay No Chelois --++ ++-t- +++ +-+ -+-++ No Concord Yes DeChaunac Yes Delaware +.,. + - + [3] + + • + No Dutchess ...,.._++ -+ ++ ++ + No ? ? Elvira ++ -+ -r++ + ++ ++ No No + + Einset Seedless ++-t- ++ -+-++ ? ? + ? ? ? ? Foch ++ ? +-t-+ + Yes ++ ? Fredonia ++ ..._..,..+ ++ ? -t No ? ? Gewurztraminer ++T ++..,.- -+-t- +++ ? ? +-t+ + No ? + Himrod + ? ? ? No ? ? lves + -r++ + ? ++ Yes ? ? Melody -r++ -+4- ? ? ? ? No ? ? Merlo! ++ +..,...+ +-+ + -t--++ ...... ++ ? No ? + + Moore's Diamond +-t;-- -++ ++ ? ? ? No No ? Niagara -+-++ +++ ++ + ++- + + No No + Pinot blanc +++ T-t-T +-t-t ++ ? ? +-t+ ? No ? Pinot noir +++ +++ +++ +++ ? ? +- + + + No ++ + Riesling +++ +++ -++'1- +++ ++ -++ + No + + Rosette -t-+ ++ +T+ T ++ -t-+ ... + + + No +++ Rougeon + + + -t- + -+-++ ++ +-t- .. + .. + + + + Yes + +-t-+ Sauvignon blanc +++ +--r+ ""!"++ ++-r ? ? ~· + + ? No ? Seyval + + + + +++ +++ ++ + • + + + No Steuben + + ? ? + + No ? ? Vanessa + + + ..... + + + ? ? ? ? ? Ventura + + + + + + + + ? .,. + + No ? ? Vidal 256 + + + + + + ++ + No +++ ? Vignoles +-t- ++ ++ + + + + No ++ ?

Key to susceptibility or sensitivity: BR =black rot; DM =downy mildew; PM= powdery mildew: Bot= Botrytis: Phom = Phomopsis: Eu = Eutypa; CG =Crown gall; ALS =Angular leaf scorch: S =sulfur; K = Karathane; C=copper

Key to ratings - =slightly susceptible or sensitive; + + = modprately susceptible or sensitive; + + + =highly susceptible or sensitive: No= not sensitive; Yes= sensitive: ? =relative susceptibility or sensitivity not established

[!]Slight to moderate sulfur and Karathane injury may occur even on tolerant varieties when temperatures are 85 degrees F or higher during or immediately following th£~ application

[2]Copper applied under cool. slow-drying conditions is likely to cause 1njury.

[3]Berries not susceptible

We wish to thank the New York CooperatiVe Extension SeNICE' for the use of this table.

89 TABLE 5. Harvest Restrictions for Grapes/Fungicides (consult label for complete restrictions and limitations)

DAYS BETWEEN FINAL SPRAY AND HARVEST FOR COMMON FUNGICIDES

Trade Common Harvest Restrictions-Days before harvest Namesr Names and Limitations (maximum amount per season)

Bayleton triadimefon 14 (18 oz) Benlate benomyl 7 Captan 1 captan 0 (24 lb) Ferbam ferbam 7 Dithane M-45 mancozeb 66 Manzate 200 mancozeb 66 Penncozeb mancozeb 66 Nova myclobutanil 14 (1.5 lb) Rovral iprodione 0 Rubigan fenarimol 30 (19 fl. oz) Sulfur sulfur 0 rwhere trade names are used, no discrimination is intended and no endorsement by the Cooperative Extension Service is implied. Not a complete list.

*Limited number of applications allowed or other restrictions apply--REFER TO LABEL DIRECTIONS

1Captan has a 4-day re-entry limitation on all food crops (read the label for further information).

90 TABLE 6. Harvest Restrictions for Grapes/Insecticides (consult label for complete restrictions and limitations.

DAYS REQUIRED BETWEEN FINAL SPRAY AND HARVEST FOR INSECTICIDES AND MITICIDES

Trade Common Harvest Restrictions/Limitations NamesT Names (days before harvest)

Cythion malathion 3* Diazinon diazinon 18 Guthion azinphosmethyl 10 lmidan phosmet 14 Kelthane dicofol 7

Lannate methomyl 1 /148 Lorsban chlorpyrifos 35* Malathion malathion 3* Marlate methoxychlor 14 Penncap-M encap. methyl parathion 14

Phosdrin mevinphos 5 Rotenone rotenone Sevin carbaryl 7 Thiodan endosulfan 7 Vend ex hexakis 28*

TWhere trade names are used, no discrimination is intended and no endorsement by the Cooperative Extension Service is implied. Not a complete list.

*Limited number of applications or amount of formulation allowed or other restrictions apply. REFER TO LABEL DIRECTIONS alannate - first number refers to table grapes and second number refers to wine grapes. Refer to label directions.

91 GRAPE PHYLLOXERA Murdick J. Mcleod and Roger N. Williams Department of Entomology OARDC/OSU Wooster, OH 44691

INTRODUCTION Grape phylloxera, Daktulosphaira vitifoliae (Fitch), is a serious pest of commercial grapevines worldwide. This tiny insect forms galls on leaves and roots of grapevines. It is believed that this insect originated in the Eastern United States, where damage is now most prevalent on leaves of French­ American hybrid grapevines. High populations of foliar phylloxera can result in premature defoliation, reduced shoot growth, and reduced yield and quality of the crop. Life Cycle Grape phylloxera has a complex life cycle (Figure 1). They overwinter either as a winter egg under the bark of older canes or trunks or as nymphs on grapevine roots. The winter egg (Figure lA) gives rise to the fundatrix, or stem mother, which moves to a nearby shoot tip and begins feeding. Feeding by the phylloxera elicits gall formation, and the female becomes enclosed within a small, spherical gall on the underside of the grape leaf. This parthenogenetic female is capable of producing several hundred eggs. First instar nymphs, or crawlers, emerge and move out of galls to nearby shoot tips where they begin feeding and thereby initiate formation of new galls. There are three to five generations of foliar phylloxera per season in eastern North America (Figure 18). Throughout the summer a certain portion of the foliar crawlers move actively or passively to the soil surface. These crawlers may move through cracks in the soil and eventually reach grapevine roots. Phylloxera may also overwinter on grapevine roots as first or second instar nymphs (Figure IC). As soil temperatures increase, crawlers resume feeding. Feeding by phylloxera on grapevine roots results in two types of galls. Nodosities are galls formed on small, apical rootlets which are generally thought to result in little damage to the vine. Tuberosities are galls formed on larger, older portions of the root which, if sufficiently abundant, may eventually result in death of the vine. From July through October, some root-infesting phylloxera develop wing buds and eventually become fully winged adults (Figure lD). Alates emerge from the soil and deposit two types of eggs, a larger egg which results in a female and a smaller egg which gives rise to a male. These sexual forms (Figure IE) mate and the female deposits a single overwintering egg under the bark of older canes or trunks, thus completing the complex life cycle.

92 Figure 1. Life cycle of grape phylloxera, Daktulosphaira vitifoliae (Fitch), (After Williams, 1938). (A) Winter egg. (B) Foliar form (Gallicola). (C) Root form (Radicola). (D) Winged adult. (E) Sexual stage. w~~~ ~ Sexual A ~J:rt:T'f.! for:~ (~B~·'·.':::\ M !fTI Wander Q to other ~ 0 leaves .W Cycle on ~ leaves , w~~'::~~o ~ YJ...~~ other vines ~~

I Ill \._)' D ~ V~\ Cydeon W--11:t'111\ roots ~, \.~)

Description This aphid-like insect is very small and difficult to see with the unaided eye. Galls formed by phylloxera are more readily identified than the insects. Galls on leaves are small, spherical growths on the underside of the leaves, with the opening being on the top. Phylloxera feeding on roots also results in small galls either on apical rootlets or on older portions of the root. These insects generally occur in groups on both leaves and roots and the yellowish color of the insect and their eggs is useful in recognition.

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