Viticulture and Enology Extension News Washington State University

Spring 2012 CONTENTS Note from the Editor

What a difference a year can make! At this time in 2011 we were assessing the extent of winter damage, recovering from the Botrytis management bills from 2010, VITICULTURE and wondering when spring was going to arrive. Now in 2012 we are planning more 2011 Vintage Review...... Page 2 appropriate canopy management and chemical control strategies for disease management in case the season is cool and wet, enjoying the fact that we have escaped USDA Cold Hardiness...... Page 4 major winter damage, and are shocked by the early emergence of daffodils, flowering cherries, and sage rats. Pest Management Guide...... Page 4 As VEEN celebrates its 1st anniversary, we hope you enjoy this edition. We are Mealybug Update...... Page 5 certainly enjoying the birthday bubbly-- and the anticipation of what the 2012 vintage will bring! Drosophila Update...... Page 6 Irrigation Scheduling...... Page 8 Michelle Moyer Viticulture Extension Specialist WSU-IAREC ENOLOGY Tannin Additions...... Page 9 Maceration: Part II...... Page 10

OTHER NEWS Irrigated Ag List Serve...... Page 9 People Profiles...... Page 12 Find us on the web: Calendar of Events ...... Page 12 www.wine.wsu.edu/research-extension Information when you need it. That is the power of the internet! Visit the WSU Viticulture and Enology Research and Extension website for valuable information regarding research programs at WSU, timely news releases on topics that are important to your business, as well as information regarding upcoming workshops Editor and meetings. Michelle Moyer, PhD It is also a valuable site for downloading our most recent Extension publications, as well as finding archived articles and newsletters you can print on demand. Find WSU Extension programs and employ- quick links to AgWeatherNet, the Viticulture and Enology Degree and Certificate ment are available to all without discrimi- programs, as well as to other Viticulture and Enology related resources. nation. Evidence of noncompliance may Find us on Facebook be reported through your local WSU Ex- tension office. Go to: www.facebook.com/WSU.Vit.Enol.Ext and “Like” the page!

1 2011 Overview: The Silver Lining in Summer Clouds By Michelle Moyer, Federico Casassa (PhD Student), and Jim Harbertson, WSU-IAREC

From the Vineyard quality. Federico Casassa and Dr. Jim By Michelle Moyer Harbertson discuss the outcomes of the 2011 grape vintage on wine quality As the AgWeatherNet reports roll in in “From the Crush Pad”. regarding warmer temperatures and spring rains, it is hard to take a retro- Freeze damage and retraining. As dis- spective look at 2011 with the 2012 cussed in the Fall 2011 issue of VEEN, growing season teasing us from the the cool, wet spring of 2011 may have not-so-distant future. We have a lot to been crucial to those vineyards recov- learn from history, however, even if that ering from the Thanksgiving Freeze history was only a few months ago. of 2010. In fact, many vineyards re- covered at an unexpected rate, and in Cool springs, prolonged bloom, and some cases, vine vigor translated into extended véraison. The “hot” topic of uncontrollable growth and inappropri- the 2011 growing season was the ut- ate internode length for future spur ter lack of summer. Fashionably late, positioning. Why was this, and how Figure 2- Extended bloom periods resulted in summer did not show until August. The can we learn from this situation to help clusters at various stages of development within cool spring temperatures delayed both prevent these retraining issues in the the vineyard block. Not only can this be challeng- budbreak and flower by 2 to 4 weeks, future? ing for downstream development and ripening, putting the 2011 vintage behind the but can also create problems when managing notoriously cool 2010 vintage on a cal- It appeared that the largest contributing powdery mildew. Photo by Michelle Moyer. endar comparison. But that late arrival factor to excessive vine vigor in retrain- tractor driving speed. These factors of heat came at the necessary time to ing situations was the lack of consider- are important in low-pressure years, bridge the gap between “average” de- ation of the available nutrient reserves and absolutely critical in high-pressure velopment timing and the delayed tim- and capacity a vine with a well-devel- years. The 2011 growing season also ing seen last year. oped root system. While the retention highlighted the benefits of using such of one to three developing shoots may cultural practices as fruit-zone leaf re- The 2011 harvest lagged behind histor- be appropriate in the establishment moval and shoot thinning as necessary ical average dates for most locations, phase of vineyard development when partners with chemical controls in ef- however, those locations that complet- the vine has a small root system, one fective management programs. While ed bloom within in a reasonable time to three developing shoots on a mature the intensity of a chemical regime for were still able to pick a crop. Sugars root system is simply an insufficient 2012 may change based on disease were perhaps lower than desired, and sink size to appropriately disperse the pressure, it would be ill-advised to acidity initially appeared high, but this amount of source energy available in downplay the fact that cultural strate- did not always translate into negative the spring. This root system is still ap- gies should always be used to maxi- proximately the same size and function mize chemical effectiveness. as when you would leave a full comple- ment of buds; although there is a loss 2012 and beyond. While we hope for of some reserves from the death of the the return of “normal” conditions in trunk and cordons, that loss does not 2012, let’s not forget the lessons we practically translate to reducing bud have learned in 2011. Challenging vin- number from a “normal” full bud com- tages remind us that we are fortunate plement to a few trunk-base buds (and to not deal with these conditions on an subsequent shoots). In many cases, annual basis. However, this is not an vigor was adequately controlled by excuse to be complacent; the informa- retaining ~5 base shoots, and only re- tion and experience gained from these moving the unnecessary shoots at the vintages can be extrapolated to future end of the season, after desired shoot vintages to improve our reactive mea- internode length was achieved. sures, or better yet, develop proactive strategies. Disease management. While there were some challenges in keeping the From the Crush Pad upper hand over Powdery Mildew in By Federico Casassa and Jim Harbertson 2011, there were some important lessons to be learned. First, timing is ev- There were many publicly, and private- erything. This is not simply referring ly, exclaimed adjectives winemakers Figure 1- Retraining vineyards after cold dam- to getting chemical protection on dur- throughout the state have been using age can be challenging. In many cases, control- ing the critical period of susceptibility to characterize the 2011 harvest in ling regrowth vigor is particularly tough when the (immediate prebloom to 3 weeks post Washington; ones which we will refrain age of the root system, and thus size of potential fruitset), but also referring to maintain- reserves, is not considered. Photo by Michelle Moyer. ing proper spray intervals, and slowing continued on Page 3

2 2011 Overview: con’t continued from Page 2

Table 1- Evolution of titratable acidity in Merlot wines served some rather lowed a protocol for analyzing TA in fro- through winemaking. unusual behavior zen Concord grapes (heating the sam- of the fruit acids in ples at 149°F for 1 hour), the measured Sampling Time Titratable acidity the transition from acidity of the juice approached those (g/L tartaric acid) grapes to wine. measured at this “peak” of TA and pH. Tank sample after crush 4.27 ± 0.06 Specifically, there Many winemakers have described is- was a mismatch sues with measuring acidity and have Tank sample 5 days after crush 7.82 ± 0.01 between titratable normally attributed these issues to acidity (TA) mea- sampling. It is possible that the heating Beginning of cold-stabilization 7.42 ± 0.02 sured in the fruit, procedure may improve TA estimates. (December 2011) and TA measured February 2012 6.39 ± 0.02 in the must and Chaptalization. Although statewide then in final wines. generalizations cannot be made, chap- Bottling (March 2012) 5.10 ± 0.01 On multiple oc- talization in late ripening varieties such casions, acids in as Sangiovese, Carmenere and Petit from using. Luckily, a lot can happen the fruit were lower than those in the Verdot in some cooler AVAs occurred. from harvest to barrel, and in the pro- wines, even after malolactic fermenta- Tartaric acid stabilization. There were cess, adjectives change. We planned tion. Table 1 contains data from a Mer- some issues in both red and white to divide this short report in two sec- lot trial, which represents this perplex- wines upon cold stabilization; instability tions: the first will highlight the very ing acid evolution. Initially, TA in the led to light cloudiness in some wines. well-known facts of the 2011 harvest, grapes was low, close to the levels of The haze did not seem to have any det- and the second highlights a few under- those in the tank sample after crush. rimental effect on the wines, other than the-radar results of the 2011 vintage. Once fermentation was fully active, TA the visual appeal. The haze appeared values almost doubled in some cases. to be colloidal in nature, and filtration Facts on the 2011 Vintage (Note: Fermentation samples should through a 0.45 µm membrane filter with Late harvest. As mentioned in “From be thoroughly degassed prior analysis an electrically neutral membrane poly- the Vineyard”, harvest was 2 to 3 weeks due to the acidic character of the dis- mer failed to remove the haze. How- behind. Since we had unseasonably solved CO2). ever, after filtering the wine through a cool and wet spring, this was expected. charged medium (e.g. cellulose esters) Optimum photosynthesis. August and Even more striking was that wines the haze was successfully removed. September were almost ideal, with cool tasted incredibly sour, far more acidic This haze was also easily removed by nights and only a few days surpassing than the “natural” acidity we tasted in centrifugation in the laboratory (14,000 the 95°F threshold of photosynthesis the tanks upon crushing. We are hy- rpm). Based on our observations we shutdown. pothesizing that both the skins and the think this colloid involves organic acids. pulp retained substantial amounts of Condensed maturity. A late and con- acids, which were released as a result 2012 and beyond. While we felt that densed maturity window posed prob- of heat, enzymatic activity, and mixing 2010 was a cool vintage, 2011 provided lems in terms of harvest and wine- during fermentation/maceration. We several new challenges. Despite this, making logistics. Manual labor is a plan to test this hypothesis, as it is not the overall quality for the wines made challenging issue Washington: when clear whether this phenomenon is sole- here in Prosser was quite high. How- the grape harvest is late, it overlaps ly a product of cool vintages. ever, we too are hoping for a warmer with apple harvest, which is by far more 2012! profitable for pickers. As an aside, we found that if we fol-

Lesser-Known Facts Berry size. The 2011 vintage surprised many winemakers with unusually large berries, even in varieties such as Cab- ernet Sauvignon. For example, in one of our research vineyards, Cabernet Sauvignon berries were 18% larger than 2010, and 22% larger than those from (a warmer) 2009. Larger berry sized resulted in larger volume of juice being received than what was forecast, which in turn resulted in slight under- estimation of barrel stocks and tank space needed for the 2011 harvest.

Acidity. While most winemakers were Figure 3- Wine showed interesting acid evolution in 2011, something that warrants further investiga- expecting a “high acid” vintage, we ob- tion. Photo by Federico Casassa.

3 USDA Plant Hardiness Zone Map Updated By Michelle Moyer, WSU-IAREC

The USDA-ARS has released an up- limit production. dated Plant Hardiness Zone Map. The These extreme information presented in the map can weather events be used to assess if different plant spe- are not always cies, and varieties, will thrive at your apparent in av- site or suffer routine dieback due to erages. freeze damage. For example, if For grape growers, they are a great the extreme low initial information source in determin- temperatures for ing if a site is suitable (i.e. winters are a given site over not too cold) for grape production, and five years were: which species (Vitis vinifera, V. labr- 8ºF, -2ºF, -7ºF, usca, or various hybrids) would be the -15ºF, 0ºF, the most appropriate given winter temper- average would ature limitations. be -3.2ºF.

Plant hardiness zones are constructed For V. vinif- New 2012 USDA Plant Zone Hardiness maps are available for download at: using the average of the annual ex- era this is an http://planthardiness.ars.usda.gov treme low winter temperatures (i.e. appropriate the coldest temperature recorded that average low temperature (Zone 6b), website, or the new interactive inter- year) over a 30 year period. If your but that one in five year event of -15ºF face can be used down to zip-code location has changed ratings, please could result in substantial cold damage specific zone information. keep the following in mind: While these (of course, this is moderated by the average absolute low temperatures do timing of the extreme cold temperature Unlike past editions, posters of the provide a guide as to whether a plant event relative to vine cold hardiness maps have not been printed, but the will survive a location’s winter on a acclimation). download options from the USDA web- routine basis, the occurrence of ex- site allow you to print them in a variety treme low temperature events can still Maps can be downloaded from the of size options. WA Grape Pest Management Guide- Expanded for 2012! By Gwen Hoheisel, WSU-Extension

The Pest Management Guide fungicide resistance management, and for Grapes in Washington is an there is a section with clear instruc- essential for any grower or con- tions regarding resistance manage- sultant. It contains information ment practices and strategies. If you on pesticide safety, weeds, thought disease control in recent years insects, diseases, nematodes has been hard, imagine it without the and nutrient management. availability of our key fungicides.

Each section begins with a Where can you get it? The guide is brief description of the biol- available for purchase online at: ogy, scouting techniques, and cultural controls for the vari- https://pubs.wsu.edu ous pests. Then a chart provides chemical control options or at any County Extension offices: throughout the season. https://ext.wsu.edu/locations New and improved! While the guide is updated every year The publication number is EB0762. by WSU and USDA experts, The price is a nominal $8.50 to cover this year saw some significant the cost of printing. changes. The disease section was expanded by almost 14 Use this guide to develop a preliminary pages, with information cov- pest management plan before the sea- ers many new chemicals on son starts. Modifying your plan as the the market to control powdery season or pest pressure changes is mildew and Botrytis bunch rot. easier than designing one on the fly! Extensive attention is given to

4 Mealybug Pheromone Traps: How Many Do You Need? By Brian Bahder (PhD Student), WSU-IAREC The sex pheromone for the grape activity occurred in the middle to end mealybug was recently synthesized of June. After a few weeks, a second and is now commercially available flight occurred, and peaked around mid for implementation in monitoring pro- to late August (Figure 1). Adult male grams. This pheromone (trans-alpha- flying activity appeared to cease at the Necrodyl isobutyrate) attracts the adult end of October. male mealybug. Their presence or ab- sence in a vineyard can be used as a As expected, more adult males were proxy for the female grape mealybug. collected overall when trap density was at 8 traps per 30 acres, versus 4 traps Pheromone traps are an excellent means of de- This method of capture and monitoring or 1 trap per 30 acres. This is likely the tecting the mealy bug in your vineyard. But how provides a faster and more economi- result of simply having more available many do you actually need? cal means to monitor for the presence traps in the vineyard, considering the of the grape mealybug. The traps are average number of adult males per trap also commercially available, making was not significantly different across Grape Mealybug them easy to obtain. the different trap density treatments. The take-home message: There is no Monitoring Trials were conducted at WSU-IAREC economic incentive to placing more in Prosser, WA in 2009, 2010, and than one trap in a 30 acre swath of Curious about your vineyard’s 2011 to determine the optimal trap vineyard! grape mealybug population? Vi- density (number of traps needed in a ticulture entomologists at WSU- vineyard bock) to effectively monitor for Why is knowing when adults emerge IAREC are asking WA grape the grape mealybug. Trap densities of and fly important? Their flight pattern growers to participate in a grape one, four, and eight traps per 30 acres can be used as a measure of when mealybug monitoring program. were tested in Concord and Vitis vinif- early instars are present, and this is a This project is aimed at gaining era vineyards in the Prosser and Pat- critical stage for chemical intervention. an understanding of what grape erson area. Adult females are not susceptible to in- mealybug populations are doing, secticides, so applications need to be and if their behavior is different in Weekly trap data (number of adult made when there are young. different locations. This monitor- males per trap) were collected over the ing will be done using pheromone course of the growing season. Results Monitoring of grape mealybug flight traps (image below). from 2010 are seen in Figure 1. Adult patterns will continue through 2012 to male mealybugs started to fly around ensure previous observations are an- Growers are responsible for trap the beginning of May, and peak flight nually consistent. costs and placements, but the participating scientists will do the trap counts and will email weekly updates to vineyard managers. Currently, recommendations are set at 1 pheromone trap per 30 acre vineyard block.

For more information regarding cost and instructions, please contact Brian Bahder at:

[email protected]

Figure 1- Three different pheromone trap densities were placed within a 30 acre vineyard block, to determine the minimum number of traps needed for measuring adult male mealybug seasonal flight patterns. In this study, 1 trap was sufficient to detect the two key flight periods in 2010.

5 Drosophila suzukii: No Longer Code Red for WA Grapes By Luz Denia Barrantes-Barrantes and Doug Walsh, WSU-IAREC

In 2010, the threat of Drosophila su- ries (1.45 flies zukii (formerly Spotted Wing Drosoph- per trap). ila) was an important concern for soft fruit growers. As a part of the monitor- Fortunately, for ing process for this new, invasive pest, grape growers a second year of monitoring was con- in WA, it ap- ducted in Benton and Franklin counties peared that D. in 2011. suzukii has low overall preference for both Until recently, Drosophila su- juice and wine zukii was commonly known grapes (Figure 2). as Spotted Wing Drosophila (SWD). However, this com- Concord grapes mon name is under revision were not highly Figure 1- Nalgene traps were used to bait and trap for Drosophila suzukii. by the Entomological Society favored (0.15 Photo by Luz Barrantes-Barrantes. of America, so all references flies per trap), to the fly will be done using with only a slight increase in preference and sugar. When temperatures cooled, its scientific name. for wine grapes (0.34). the apple cider vinegar is the most attractive bait (Figure 3). This was despite having a high concentration of traps in these two crops (25% Recommendations. Although moni- Nine crops were selected (Table 1) for toring and other reports suggest that D. monitoring in 2011, due to previous of the total traps in Concord, and 13% of the total traps in wine grapes). This suzukii will likely not become a major reports identifying them as potential pest in grapes, it is important to prac- hosts of D. suzukii. strengthens the argument that grapes appear to be a non-preferential crop for tice timely harvest. D. suzukii. A total of 180 traps were placed in the If you have damaged or infested fruit, crops with a minimum distance of four remove it from the vineyard and de- meters between each trap (Figure 1). When comparing the bait types (ACV vs. fermenting yeast), flies appeared to stroy it. We have low infestation in Two trap types were used: apple cider grapes, so let’s keep it that way! vinegar (ACV; 126 traps), and ferment- prefer the fermenting yeast (1.13 flies ing yeast (yeast, sugar, and water; 54 per trap) over the ACV (0.97 flies per trap) (Figure 3). If you want to do your own monitoring, traps). use ACV bait during the months where the average temperature is lower than Traps were checked biweekly from The effectiveness of the bait appears to be related with the ambient tem- 68°F and fermenting yeast during March to May, and weekly from June warmer months. See the sidebar on to November. perature. When the temperatures are moderate (>68°F) the flies are more at- this page for the different bait recipes. Cherries were by far the most attractive tracted to the mixture of yeast, water, continued on Page 7 for D. suzukii (averaging 2.78 flies per trap), followed by blackberries/raspber- Table 1- Crops monitored for Drosophila suzukii in 2011.

Crop Number of Traps BAIT RECIPES Apple 6 Apple Cider Vinegar: Add 3 oz of natural flavor apple ci- Apricot 8 der vinegar (5% acidity) and 3 Blackberry 30 drops of liquid dish detergent to your trap. Blackberry/Raspberry 4 Blueberry 35 Fermenting Yeast: Mix 1/3 cup dry active yeast, 2/3 Cherry 17 cup of sugar, 1 gal of water and 3 drops liquid dish Concord Grapes 46 detergent. Place 3 oz of this Peach 10 mixture in your trap. Wine Grapes 24

6 Drosophila suzukii: con’t continued from Page 6

Drosophila suzukii Crop Preference in 2011

3.0

per trap per 2.5

2.0

1.5

1.0 Drosophila suzukii

0.5

0.0 Average of

Apple Cherry Peach Apricots Blueberry Blackberry Juice grapes Wine grapes

Blackberry/Raspberry Crops under study

Figure 2- Drosophila suzukii had clear crop preferences in the Benton and Franklin county area of Washington in 2011. The good news for grape growers is that grapes are not among them.

Trapping Bait Preference of Drosophila suzukii 9 A CV 8 Yeast/sugar/w ater 7

per trap per 6 5

D. suzukii 4 3 2 Average of of Average 1 0

Nov-7 Mar-21 Oct-31 Nov-21 April 04-05April 18-19May 02-03May 16-17May 30-31 July 04-05July 11-12July 18-19July 25-26 June 06-07June 13-14June 20-21June 27-28 October 3-4 August August01-02 August08-09 August15-16 August22-23 29-30 OctoberOctober 10-11 October 17-18 24-25 SeptemberSeptember 05-06September 12-13September 19-20 26-27

Weeks of sampling. March to November, 2011

Figure 3- Line traces depict the average number of Drosophila suzukii caught over the course of the growing season. During the warmer summer months, D. suzukii flies preferred the fermenting yeast bait, but as temperatures cooled in the fall, the apple cider vinegar (ACV) bait was preferred.

7 Irrigation Scheduling for (Wireless) Washington By Troy Peters, WSU-IAREC

It is irrigation season, once again! This (evapotranspiration) estimates from begin to see water stress (also called brings up age-old questions such as: WSU’s AgWeatherNet (AWN; weather. the management allowed deficit , or “When do I turn the water on?” and wsu.edu). It also allows modifications MAD). For maximum growth and pro- “How long do I leave water on?” for improved accuracy by users. The duction, the soil water content should model can be corrected at any time be maintained between the field ca- Improved irrigation scheduling has tre- using soil water measurements or esti- pacity and MAD. To induced stress, mendous public and private benefits mates. It readily displays useful charts the soil water content should be main- including better yields, improved crop and tables for visual evaluation of soil tained somewhere underneath MAD, quality, lower pumping energy costs, water status and model inputs. but above the wilting point. lower labor costs, and decreased loss of costly fertilizers due to leaching. After logging in, users can define spe- From the Daily Budget Table (Figure While a variety of irrigation scheduling cific setting for individual field sites 1c) the user can see the soil water aids are available, they are not widely (Figure 1a). This involves: (i) Naming deficit (maximum amount of water that used and most of them are not adapted the field site (e.g. Joe’s Cab Vineyard), can be added without losing it past the to Washington. The common reasons (ii) Selecting the year, (iii) Selecting the root zone) and edit the rainfall and ir- behind their lack of adoption are: (i) crop grown, (iv) Selecting the soil tex- rigation amounts. In addition, the user they are too complicated, (ii) they are ture, and (v) Selecting the AWN weath- can correct the soil water content using difficult to learn, and (iii) they are time er station that is closest to their site. on-site soil moisture measurements or consuming to use. In addition, growers estimates. rarely have time, or desire, to complete Based on these inputs, that particular the associated “desk-work.” field site is then set up with default val- The model accuracy can be improved ues for the soil’s water holding capacity by revising the default soil and crop To fill this need, Washington State Uni- and average crop growth characteris- growth parameters and dates in the versity has developed a simple, user- tics. Rainfall and daily crop water use Advanced Field Settings. A complete friendly, and mobile irrigation schedul- estimates are imported from the asso- user’s manual is available online and ing tool. Irrigation Scheduler Mobile ciated AWN weather station. a full screen version that runs within is a free irrigation scheduling tool for AWN will soon be released. The Irriga- doing simplified check-book style irri- The soil water content is shown on the tion Scheduler Mobile is available at: gation scheduling that is designed for Soil Water Chart (Figure 1b) along with http://weather.wsu.edu/is/ use on a smart phone or desktop web the maximum amount of water that the browser. It is easy to set up and au- soil can hold (field capacity), the wilting For more information, contact Troy Pe- tomatically pulls daily crop water use point, and the point where the plant will ters at [email protected].

A B C

Figure 1- Irrigation Scheduler Mobile has an easy-to-navigate user interface. a) Users can provide field site-specific information; b) Soil Water Content Chart that provides information regarding water levels necessary to maintain plant water status or induce water stress. Values are imported in from AWN, or can be added based on in-field measurements; c) Daily Budget Table. The colors in this table indicate the soil water status: green = maximum growth, yellow = nearing water stress, red = water stress.

8 New email List serve for Irrigated Agriculture and V&E By WSU-Extension As growers in the PNW, WSU Exten- email you receive from us. sion knows you have a unique set of For those currently receiving interests and production portfolio. We emails through the various Vi- Topic Areas Include: want to provide you with the informa- ticulture and Enology Exten- Tree Fruit – apple, cherry, stone fruit, tion you need, but don’t want to over- sion list serves, we will be con- nursery, automation/mechanization load your inbox. solidating to this new service. Grapes – juice, wine, table, winery Don’t let the title “Irrigated Ag- Other Small Fruit – blueberry, raspberry To do this, we have set up an email in- Vegetables – potato, onion, sweet corn, formation delivery service that you can riculture” fool you, we will still peas, carrots, other vegetables customize to your information needs. be covering topics relevant to Cereals/Row Crops – wheat/small You can choose to receive information Eastside and Westside grape grains, corn (grain and silage), dry on your unique set of interests, and you and wine production. edible beans, alternative crops can change those choices at any time. Forages – alfalfa, timothy, other grass- will be able to see all the educational es/legumes, mint We have chosen email to deliver this events relevant to irrigated agriculture Livestock – cattle, swine, sheep, goats, information because it is a proven tech- on one calendar. pasture management nology, and it gives you the ability to Ag Systems – high residue farming, receive it at home, in the office, or on We hope this new service will fit your soil quality/health, organic ag, direct your phone if you want. It also allows needs. If you have ideas for improv- marketing, small farms us to send you time-sensitive informa- ing this service, please let us know by Water and Irrigation – center pivot ir- tion as soon as we have it. To sign up, sending an email to: rigation, drip irrigation, surface irriga- go to our website and click the “Sign up tion, water availability/rights now” link. [email protected] This service managed by WSU Region- http://extension.wsu.edu/irrigatedag Finally, if you ever need to change al and Statewide Extension faculty. For your interest choices or cancel your grapes and wine, this includes: Gwen While there, notice the new Irrigated subscription, you can easily do this by Hoheisel, Michelle Moyer, and Thomas Agriculture Events calendar. Now you clicking the link at the bottom of every Henick-Kling. Evaluation of Tannin Additives to Red Wine By Jim Harbertson, WSU-IAREC and Mark Downey, DPI-Victoria, Australia

Tannins are an important part of wine a Merlot wine during barrel ageing, at in the wines and were discriminated quality and are frequently added dur- various concentrations ranging from in sensory analysis with higher brown ing winemaking. Tannins are added to 60 to 300 mg/L. Interestingly, only the color, bitterness, and earthy charac- wine for a range of reasons including 300 mg/L addition had a significant inter. Other parameters were rated with effecting the sensory properties of the crease in measurable tannins in the fi- lower intensity. The initial red wine had wine, deactivating enzymes, or bolster- nal wine product. ~550 mg/L tannins, which is about av- ing the amount of antioxidants. Tannin erage for all red wines, while the addi- additives, also referred to as enologi- Given the impurity of the enological tions increased the wine tannin from 50 cal tannins, and their impact on wine tannin products, it was not surprising to 250 mg/L. are poorly documented, however, their that no differences between the control use during fermentation and cellaring is and treated wines were observed. This Generally, the recommended addition widespread in the wine industry. prompted a second experiment that rates by tannin manufactures were too greatly increased the amount of eno- low to impact the measured tannin con- In collaboration with Chateau Ste. Mi- logical tannin addition to wine. centration of Merlot and Cabernet Sau- chelle, scientists from DPI-Victoria vignon wines from Washington (USA). (Australia), UC-Davis, and WSU sought In the second experiment, grape (con- The oak- and grape-based enological to characterize a range of enological densed) and oak (hydrolyzable) eno- tannin additions had a measurable im- tannins and their contribution to wine logical tannins were added to Cabernet pact on wines, but unfortunately, they quality. Numerous enological tannins Sauvignon wine post-pressing at rec- also had a negative impact on sensory were surveyed for protein precipitable ommended (150-200 mg/L) and high character. tannins and iron reactive phenolics. In (600-800 mg/L) rates. Wines were ana- general, the enological tannin products lyzed for anthocyanin, small and large In conclusion, enological tannins are were relatively impure, ranging from 12 polymeric pigment, precipitable tannin, added to wines for a range of reasons. to 48% tannin. iron reactive phenolics and sensory This research suggests many enologi- character. cal tannin additions may be unjustified In this same study, one enological tan- and have limited or negative impacts nin product, which was a mixture of Following all enological tannin addi- on wine quality. grape and oak tannins, was added to tions, tannins were readily measured

9 Maceration Part 2: Focus on Color By Federico Casassa (PhD Student) and Jim Harbertson, WSU-IAREC

The color of red wine has always been are absorbed in the visible range of the at the heart of human fascination, and electromagnetic spectrum. A maximum this holds true for both scientists and peak of absorbance at 520 nm corre- Did you know? winemakers. sponds to the absorption of red light and this is the dominant color spec- Raymound Brouillard proposed Raymond Brouillard, a world-renowned trum in red wines. In fact, anthocya- that the structural simplicity phenolic chemist who resolved the nins strongly absorb light at 520 nm, a of grape anthocyanins and the structure of several anthocyanins physical-chemical trait that is used for lasting color of red wine should in flowers, fruits and legumes was their quantification. On the other hand, be considered as “The French amazed by the fact that even though the more “lifted” or “flat” the spectrum Paradox II”. the structure of grape anthocyanins is, the more or less “visible” color the is among the simplest encountered wine displays, respectively.

Figure 1- Evolution of the visible spectrum of a Malbec wine produced with different skin contact regimes, ranging from 4 hours to 21 days. Source: INTA, 2009. in higher plants, the color of red wine As shown in Figure 1, the wine made How can this be? It has to do with the is more stable than the color of other with a skin contact time of 4 hours is nature of the anthocyanins. During anthocyanin-based food products (1). pink in color. This wine is, for all practi- post-fermentation, a decrease in the Why is this so? cal purposes, a rosé wine presumably concentration of anthocyanins is typi- devoid of structure and mouthfeel due cally observed. This apparent loss is An intriguing aspect of red wine color to the minimal or non-existent extrac- the result of the combined effects of that has been recently demonstrated tion of tannins. Within 48 to 96 hours, degradation reactions (mainly non- is that more skin contact time during the maximum color of the wine is at- enzymatic oxidations), electrostatic maceration does not necessarily result tained. Color seems to remain stable binding (3), and to the incorporation of in more immediate color (2). While the thereafter, as evidenced by the spec- the anthocyanins into a new family of final color of red wine is highly depen- trum of the 8-day wine, which does not pigments dubbed “polymeric pigments” dent on the grape variety, there are in- differ from the 96-hour wine. (4,5). trinsic aspects of the winemaking process, such as skin contact time, that Beyond 96 hours, however, other com- Are we really losing color? The answer modulate how color is extracted. pounds such as tannins are extracted is yes, at least in the short term. This thus contributing to the mouthfeel of is the rationale followed by winemak- Color evolution during maceration. the wine. The same holds true for the ers who macerate for 5-7 days, in or- A snapshot of the maceration process 8-day wine. Finally, the spectrum of the der to obtain deeply colored, young red in a Malbec wine made on an industrial 21-day skin contact time wine is more wines, which are designed to be con- scale and using different skin contact “flat” than the spectrum of the 96-hour sumed quickly. The interesting part is regimes (4 hours to 21 days), is seen wine. The conclusion is obvious: the what happens in the long term. While in Figure 1. The insets are the actual 21-day maceration wine has less color a 21-day maceration results in a wine appearance of the finished wines. The than its 96-hour or 8-day maceration with lower color density than a 96-hour spectra show which color wavelengths counterparts. continued on Page 11

10 Maceration Part 2: con’t continued from Page 10

Figure 2- Evolution of: a) anthocyanins; b) tannins; and c) large polymeric pigments during maceration and early aging in Washington State Merlot wines. Control wines were made with 7-day skin contact time and extended maceration wines were made with 20-day skin contact time; d) hypothetical polymeric pigment structure. Source: Harbertson et al. 2009 (5). maceration, it contains something that countered during winemaking), which REFERENCES: its 96 hour counterpart does not: tan- renders them more stable. In fact, one nins. of the virtues of extended maceration 1) Brouillard, R., Chassaing, S. and may be the gain of more stable color A. Fougerousse. Phytochemistry, Although not directly verifiable in the together with a modulation of the as- 64:1179-1186. short term, it is likely the 21-day mac- tringent properties of the tannins as a 2) Casassa, L.F., M. Mireles, E. Har- eration wine will develop a more stable result of enhanced polymeric pigment wood and J. F. Harbertson. 2011. color due to the progressive formation formation (2). American Society for Enology and Vi- of polymeric pigments. ticulture Annual Meeting. Grape and Conclusion. Red wine color is com- Wine phenolics Technical Abstracts. Polymeric pigments explain the high plex and much research is still devoted 70 pp. stability of red wine color. Polymeric to understand the biochemical basis 3) Cheynier, V., M. Dueñas-Paton, E. pigments are a heterogeneous mixture of its development and evolution dur- Salas, C. Maury, J.M. Souquet, P. of monomeric, oligomeric and polymer- ing winemaking. From the perspective Sarni-Manchado, and H. Fulcrand. ic tannins that have an anthocyanin at- of color, maceration is a trade-off: with 2006. Am. J. Enol. Vit. 57:298-305. tached to it (Figure 2d). longer maceration times, more tannins 4) Haslam, E. 1998. Practical polyphe- are extracted but this is at the expense nolics - From structure to molecular By virtue of the glucose moiety of the of some loss of anthocyanins (Figure recognition and physiological action. anthocyanin portion, they are water- 2a-c). However, the anthocyanins that Cambridge University Press, Cam- soluble and are less astringent than remain are likely to persist longer in the bridge, UK, 422 pp. the intact, original tannin (4) More- wine matrix, and might soften the as- 5) Harbertson, J.F., M. Mireles, E. Har- over, unlike anthocyanins, polymeric tringency of red wine as they become wood, K.M. Weller, and C.F. Ross. pigments tend to be more resistant to progressively incorporated into poly- 2009. Am. J. Enol. Vit. 60:450-460. pH changes, temperature and bisulfite meric pigments. bleaching (3) (all aspects normally en-

11 Personnel Announcements in V&E

Troy Peters Visiting Scholars Gary Grove Associate Professor Viticulture Professor WSU-IAREC WSU-IAREC WSU-IAREC

Congratulations The Keller lab is continuing its tradition WSU-IAREC’s to WSU Irrigation of international collaboration in 2012, Gary Grove is a Extension Special- recently hosting Francisco Gonzalez coauthor on a pa- ist Troy Peters Antivilo, and Giulio Carmassi. per that received for his recent ten- the 2012 American ure and promotion Francisco joined the lab to develop Journal for Enology award! Dr. Peters skills in cold hardiness and microcli- and Viticulture best has been a faculty mate evaluation that he will use in his paper of the year in member at WSU native Argentina. Cold damage has Viticulture. The pa- based at IAREC been implicated in vine death and poor per, titled Powdery in Prosser since productivity in some new, high-eleva- Mildew Severity as 2006. His research focuses on irrigation vineyards in Mendoza, but efforts a Function of Canopy Density: Associ- tion management for improved farm to properly identify it were limited. ated Impacts on Sunlight Penetration profitability and environmental stew- and Spray Coverage and looked at the ardship. Giulio is working on different projects influence of canopy management on relating to irrigation, including the im- disease control and spray efficacy. He also manages the Comprehen- pact of soil moisture on budbreak and sive Irrigation website for WSU (http:// early shoot growth, and the effects of Coauthors included Craig Austin, Jim irrigation,wsu.edu), where a multitude regulated deficit irrigation (RDI) on vine Meyers, and Wayne Wilcox (Cornell of irrigation information is available for physiology. RDI is not routinely prac- University). Work supporting the paper growers and agronomists in the PNW. ticed in his native Italy, so understand- was done in NY and WA. Congratulations Troy! ing it is important for industry education. Congratulations Gary! Calendar of Events

Date Description 5 Apr 2012 Fieldman’s Breakfast, Prosser, WA 3 May 2012 Fieldman’s Breakfast, Prosser, WA OSU/USDA/WSU Pest Scouting Workshop, Milton- 8 May 2012 Freewater, OR 7 Jun 2012 Fieldman’s Breakfast, Prosser, WA 18-22 Jun 2012 ASEV National Conference, Portland, OR 5 Jul 2012 Fieldman’s Breakfast, Prosser, WA 2 Aug 2012 Fieldman’s Breakfast, Prosser, WA 8 Aug 2012 Advanced Wine Analysis Workshop- WSU TriCities 10 Aug 2012 Washington Grape Society Field Day, Prosser, WA 15 Aug 2012 Wine Fault Detection Workshop- WSU TriCities 6 Sept 2012 Fieldman’s Breakfast, Prosser, WA Check the website for changes and updates to the Calendar of Events. http://wine.wsu.edu/category/events/ The next VEEN will be in August/September and is accepting events between 1 September 2012 and 31 March 2013 www.wine.wsu.edu Let Michelle ([email protected]) know of your events by: 15 August 2012