Table 2. Raw product quality of 'Orlando Seedless' and 'Thompson Seed- of the panelists preferred the texture of 'Thompson Seed less' grapes. less' to 'Orlando Seedless.' The texture of 'Orlando Seed less' was rated between "Neither Like Nor Dislike" and Titratable Soluble "Like Slgihtly." Many panelists objected to the thicker and Soluble acidity solids: solids (as% acidity tougher skin of'Orlando Seedless', preferring the "crun- Cultivar (%) pH tartaric) ratio chier" texture of 'Thompson Seedless.' This texture type is a characteristic associated with slip-skin cultivars such as Orlando Seedless 16.8 3.30 0.60 28.0 'Orlando Seedless.' The texture is often influenced by Thompson Seedless 19.0 3.35 0.85 22.3 F-test * * * berry turgidity. Improved irrigaion practices, rapid cool ing of grapes after harvest, and shrink wrapping to pre *, significant at 5% level. vent moisture loss may lead to improved berry texture of 'Orlando Seedless.' None of the panelists seemed to notice There were no significant differences in flavor between any objectionable seed reminants. 'Orlando Seedless' and Thompson Seedless', although the Overall, this study suggests thecolor and flavor of 'Or flavor of 'Thompson Seedless' was rated a little higher lando Seedless' are of comparable quality to the standard (Table 1) and more people preferred the flavor of white seedless grape, 'Thompson Seedless.' Management 'Thompson Seedless' to 'Orlando Seedless'. The flavor of practices which would improve the cluster appearance and both cultivars was rated between "Like Slightly" and "Like texture of 'Orlando Seedless' need to be researched. Spec Moderately." Comments from some of the panelists indi ifically, rounder, looser clusers and "crunchier" berry tex cated that 'Orlando Seedless' had a slightly undesirable bit ture would be desirable. Text marketing research to deter ter and astrigent flavor imparted by the skin. 'Orlando mine acceptabiliy by consumers on a large scale needs to Seedless' did seem to taste a little sweeter to many of be undertaken before final conclusions on market poten panelists than 'Thompson Seedless.' This was due to a tial of'Orlando Seedless' can be made. higher soluble solids:acidity ratio in 'Orlando Seedless' (Table 2). 'Orlando Seedless' actually had lower soluble Literature Cited solids than 'Thompson Seedless', but it also had much 1. Halbrooks, M. C. 1986. Viticulture in : The next five years. lower acidity. Proc. Fla. State Hort. Soc. 99:189-192. The texture of 'Thompson Seedless' was definitely pre 2. Mortenson, J. A. and D. J. Gray. 1987. Orlando Seedless Grape. ferred to that of 'Orlando Seedless' (Table 1). Over 80% HortScience (in press).

Proc. Fla. State Hort. Soc. 99:194-200. 1986.

EFFECT OF BUNCH AND MUSCADINE GRAPE MATURITY ON FINISHED

R. P. Bates and R. Tejada Despite the compositional differences that exist within a cul Food Science and Human Nutrition Department tivar at different stages of maturity, the wine character was University of Florida, Gainesville. FL 32611 not dramatically affected by harvest maturity, if the must

AND was standardized by chaptalization. The maturity-related ex J. A. MORTENSEN tremes in grape acidity (and to a lesser extent pH) are at Agricultural Research and Education Center, tenuated in the by cold stabilization (both species) and P.O.Box 388, Leesburg, FL 32749 fermentation (muscadine only). Consequently, mid to late and early to midseason harvesting is recommended for bunch Abstract. 'Stover1, 'Conquistador' (bunch, R. Euvitis) and 'Wel and muscadine grapes, respectively. In all cases crush pH der1, 'Noble' (muscadine, V. rotundifolia) cultivars were har should be restricted to between 3.0 and 3.5. vested at 3 or 4 day intervals over a 3 to 6 week period. Brix, pH, titratable acidity, g sugar/berry and berry weight were The chemical make up of raw material is quite influen followed during ripening. Chemical composition and wine tial in wine making and wine quality. The composition of analyses were obtained from these same cultivars at their the grapes depends on variety, climate, vineyard manage early, midseason and late harvest periods. Maturity date cor ment and biochemical processes during grape maturation related well with compositional data (R=0.90 to 0.99), except and can be assessed only byproper sampling techniques for pH. As ripening progressed, Brix and pH increased, while (4). The changes in chemical composition of grapes during titratable acidity decreased. This trend was less uniform in maturation have been extensively studied (1, 9, 10, 12). the uneven ripening 'Conquistador'. Composition data ob Flora and Lane (11) reported that in 'Cowart' (a mus tained with 100 berry samples which were hand crushed and cadine), as ripeness increased, the titratable acidity de pressed then blended and reanalyzed only approximated sub clined and pH, percent soluble solids (Brix), juice yield sequent large batch free run and press juice, respectively. and Brix/acid ratio increased. Carroll and Marcy (8) studied the chemical and physical changes during matura tion of muscadines, 'Noble' and 'Carlos'. They reported Florida Agricultural Experiment Station Journal Series No. 6671. that Brix, titratable acidity, Brix/acid ratio, pH, fructose,

194 Proc. Fla. State Hort. Soc. 99: 1986. glucose, and sucrose increased during ripening, while tit- blended juice was analyzed for Brix, pH, and titratable ratable acidity, malic acid, and tartaric acid concentrations acidity. In addition, the measurements of sugar per berry decreased. Pirie and Mullins (14) described the behavior and berry weight were used to determine maturity (13). of the total phenolic and anthocyanin content in the skin Compositional data on grapes and juice for each cultivar of grape berries in vinifera L. cv Shiraz. An increase were analyzed separately and correlation coeffecients in the accumulation of phenols and anthocyanins in the among appropiate parameters were estimated. skin accompanied maturation. Despite the important con tribution of phenols in the seed to the total phenols levels 1983 and 1984—Wine Preparation of the berry, the skin was the most important single source of phenols during wine making. Catalina et al. (9) reported Raw material. 'Stover', 'Conquistador', 'Welder' and an increase in juice yield, pH, reducing sugar, glucose, 'Noble' grapes were harvested from the same blocks as the fructose, protein, K, P, Ca, and Mg, and a decrease in 100 berry samples, stored at about 2° C for less than 5 days titratable acidity, iron, and zinc in Vitis vinifera cv. Palomino and transported to Gainesville. Crushing was performed during ripening. In addition to single parameters analyses, by passsing the fruit through a small manual grape crusher sugar/berry has been proposed recently as a particularly (in the case of small samples, 10 kg or smaller) or through useful measure of grape ripening (13). the rotary knife section of Runkles Model 17 Cider Despite these comprehensive studies on the ripening Crusher-press. The crusher was adjusted so that all berries behavior of wine grapes, there is little detailed data on were crushed but grape seeds were not broken. Three Florida-grown bunch and muscadine grapes. Experience methods of must extraction were used: 1) White wine has shown that the maturation of a given cultivar varies grape ('Stover' and 'Welder') were pressed immediately. from vineyard to vineyard throughout the State and even Crushed grapes were rack and cloth pressed at about 14.0 within a vineyard. The purpose of this study was to deter kg/cm2 for 10-20 min with 2 % rice hulls added; 2) For mine the ripening characteristics of the 4 major wine cul- 1984 red wines ('Conquistador' and 'Noble') hot pressing tivars and relate these compositional changes to wine com was used. The crush was placed in a steam jacketed kettle, position and quality. 0.072 g/kg crush of pectic enzyme (Klerzyme Liquid 200, GB Fermenation Industries Inc.) was added and the sam Materials and Methods ple was rapidly heated to 60° C and maintained for 25 min followed by pressing; 3) For 1984 red wines on-skins fer Muscadine cultivars (Welder and Noble) and two bunch mentation for 72 hr was used. The crushed sample was grapes (Stover and Conquistador) produced by typical cul placed in 20 to 60 liter covered plastic containers, inocu tivation practices (6) were harvested during the 1983 and lated with active rehydrated yeast and 0.072 g/kg of pectic 1984 seasons from the Agricultural Research and Educa enzyme and placed at 18° C. Three times a day the crush tional Center at Leesburg, Florida and processed at the was mixed. Pomace fermentation and hot pressings were Food Science and Human Nutrition Department, Univer finished by the rack and cloth operation described. sity of Florida, Gainesville. Must Preparation. White and red must were treated with 1984 Maturity Study. Fifty-three duplicate sets of one 250 and 100 ppm potassium metabisulfite, respectively, hundred berries per sample were studied in 1984 (10 sam during crushing (about 140 and 60 ppm SO2). The Brix ples of 'Stover', 7 of first picking 'Conquistador', 7 of sec was adjusted to 21 degrees with cane sugar after pressing, ond picking 'Conquistador', 15 of 'Welder', and 14 of for immediate press and hot press samples. In the case of 'Noble'). Samples were harvested at 3 to 4 day intervals for pomace treaments, the Brix was adjusted before skin con a period of 3 to 6 weeks from typical, specially marked, tact fermentation, based on the freshly crushed analysis vines. 'Conquistador' is uneven ripening, consequently, and yield data of previous years. In 1983 only, excessive two pickings were done. In the first picking, only the red must acidity was adjusted to about 0.9%, using a 21 °B berries were harvested and the green berries were allowed sugar solution. Samples were inoculated with 0.5 g/liter, to mature for the second picking. must with rehydrated Montrachet Red Star commercial For each cultivar, 4 different vines were selected at ran yeast. dom to be representative of typical locations in the vin Fermentation and postfermentation treatments. Fermenta eyard. Berry samples were taken in groups of 25: one tions were conducted at 18° C and 13° C for reds and white berry from the top, another from the bottom and the other wines, respectively in 8 to 12 liter glass carboys, fitted with two from each side of 6 bunches (for 'Stover' and 'Conquis water traps. When fermentation ceased, as reflected by tador') or groups of berries (for 'Welder' and 'Noble') lo suitable dryness when tasted for 1983 wines, or values cated one at the top, another at the bottom and the other below 0.4% reducing sugar (3) in the case of 1984 wines; from 4 clusters at each of the middle sides of the vine. Two the wines were racked under a nitrogen atmosphere into 25 berry lots taken from each of 4 vines were collected as plastic buckets, hermetically sealed, frozen at -18° C, 2 samples of 100 berries each. After picking, the samples thawed at 24°-27° C for 16 to 24 hr, pressure siphoned were kept at 2° C for a period of no more than 7 days in under nitrogen from the lees and filtered cold through sealed plastic bags. No. 7 cellulose pads in a Ertel Model EBW filter using The 100 berries were weighed, crushed, and pressed by HYFLO Super-Cell filter aid. Wines were filled into 750 hand using a fine mesh nylon press bag. The juice obtained ml screw cap glass bottles, taking care to minimize oxygen after pressing was weighed and 10 ml was analyzed for contact using carbon dioxide. Finally, wines were cased and Brix, pH, and titratable acidity. To approximate pomace stored in the dark at 13° C. contact the remaining juice was mixed with the original Analyses. Analyses of Brix, pH, and titratable acidity skins, pulp and seeds and blended for one min in a kitchen were conducted on the juice after crushing, after pressing food blender at low speed to prevent seeds crushing. This and on the adjusted must. Analyses for pH, titratable acid-

Proc. Fla. State Hort. Soc. 99: 1986. 195 ity, total phenols, alcohol, extract, color and reducing Grape analysis. Sugar level, approximated by Brix is the sugars were conducted on finished wines. Brix was deter clearest and easiest measure of grape maturity, requiring mined using a temperature corrected refractometer. Tirat- only a drop of juice on a refractometer. In all 4 cultivars able acidity (pH 8.2 endpoint) was reported as percent tar- Brix values increased fairly uniformly wih maturity (Fig. taric acid (g/100 ml) (2). Total phenols were determined 1) and were independent of extraction conditions (hand by the method of Folin-Ciocalteu (2). Alcohol and extract press and blending). This finding is consistent with data were determined by distillation and refractometer reading. obtained from numerous pressing regimes, and showed Color analyses were performed by reading absorbance this, provided pomace fermentation has not commenced values, determined on single strength white wines and red prior to pressing. Brix at crushing and after pressing is wines diluted 1:10 v/v with water using a Bausch & Lomb essentially unchanged. Spectronic 20 UV spectophotometer at 420 nm for whites Sugar/berry (s/b), a suggested index of maturity (13) and 420 and 520 nm for red wines. was not any more revealing than Brix (Fig. 2). Except for When the wines were 6 to 12 months old grape matur 'Stover', overmaturity was associated with a slight reduc ity difference were evaluated. Judges (21 or more panelists tion in s/b in contrast to Brix which either leveled off or for 1983 wines and 6 for 1984 wines) consisted of depart continued to increase. Nevertheless, since s/b compensates ment staff, faculty and students. A triangle test (difference somewhat for climate-induced dehydation (or in the case test) was used (5). Three 20 ml wine samples were pre of a humid, wet climate, hydration) it is a more sensitive sented in black wine glasses at about 20° C. Panelists were measure of maturity and worth consideration. The time at asked to taste and smell all 3 samples and decide which one which berry weight leveled out, although subject to mois was unlike the other two. Data were analyzed according to ture transfer, seemed to coincide with the viticulturist's in Amerine and Roessler (5). dependent estimate of cultivar peak ripeness (Fig. 2); whereas, s/b peaked about a week after this visual estimate. 1984—100 Berry, maturity study Titratable acidity (TA) decreased with maturity and mirrored Brix increases in all cultivars (Fig. 3). However, This maturity study was undertaken to clarify a 1983 in contrast to Brix, TA was strongly dependent upon the experiment in which sample lots of 10 kg or more of the juice extraction method. Blended samples inevitably had same grape cultivars were made into wines at 3 different higher TA than hand pressed ones. The difference was up maturity levels harvested about a week apart. These lots to 0.4% in early season bunch grapes but diminished with showed unexpected variability in composition; the antici maturity to 0.07-0.15% in overmature samples. The 0.4- pated trend in Brix and titratable acidity as a function of 0.3% difference noted in muscadines was not maturity de maturity over 3 weeks was not well defined. Therefore, a pendent. In early season hard fruit, acid is more effectively light (hand press) and a thorough (blending) extraction extracted by blending; whereas, in more mature, low acid regimen were used in the 100 berry maturity, attempting muscadines, the grape acidity of the skin is released by to relate sample composition to that of free run and press blending. It has been our experience that about 2/3 of the juice from 10 kg batches for wine. acid in mature muscadines resides in the skins, much of

Picking of Wine Samples Viticulturisfs Estimate of Optimum Early 21.0-- Grape Ripeness

19.0- -

A-A A—A 17.0- -

6/25 7/1 7/8 7/15 7/21 7/28 8/1 8/8 8/15 8/21 8/28 9/1 9/8 9/12 Picking Date

Fig. 1. Brix maturity profile and picking dates for selected grape cultivars (S = Stover, C} = First Conquistador picking, C2 = Second Conquistador picking, W = Welder, and N = Noble).

196 Proc. Fla. State Hort. Soc. 99: 1986. which can be released by extended pomace contact time (6). From the standpoint of wine stability and potential quality, must and wine pH is of critical concern (15). Figure - -3.50 4 shows this expected upward trend. In the bunch cultivars blended samples always had pH values 0.15 to 0.3 units higher than hand pressed juice. This was not the case with muscadines where a more erratic pattern was observed. Over the last 3 weeks of sampling hand pressing gave pH values 0.2 to 0.3 units higher. Blending apparently ex tracted additional diluting or buffering substances from bunch grapes and more acid from muscadines. Table 1 shows the coefficient of determintation (R2) for maturity date vs composition data. Except for the first 'Conquis tador' picking, the correlations are good and the relation ships well defined by linear or, in most cases, quadratic equations. It appears that Brix is a good predictor of TA, but not of pH. Blended samples R2 were slighty higher. In contrast, R2 for Brix vs pH and pH vs TA were lower and much more variable. Must and wine analyses. Although properly selected 100 berry samples can tell much about the ripening phenome non, the most revealing indices of maturity are must and wine composition and, ultimately, wine quality. The 1983 study consisting of 4 cultivars harvested at 3 maturities of 6/25 7/1 7/8 7/15 7/21 7/28 8/1 8/8 8/15 8/21 8/28 9/1 9/8 9/15 about a week apart are presented in Tables 2 and 3. The Picking Date trend for Brix, pH and TA was similar to, yet more vari

Fig. 2. Sugar/berry and berry weight maturity profiles of selected Flor able than the 100 berry study. Despite some large maturity- ida wine grape cultivars (Arrow designations same as Fig. 1.). induced differences in juice/must Brix, pH and TA, these

t

\ ^# . Noble B

N. ^•^Welder B ^#

. Noble H *

-o-o—f^+ ^ ft Welder H + -H H H h- 6/25 7/8 7/15 7/21 7/28 8/1 8/8 8/15 8/21 8/28 9/1 9/8 9/12 Picking Date

Fig. S.TrtratafoVe acidity maturity profiles of selected Florida wine grape cultivars. (H = Hand pressed juice analyis, B = Blended sample analysis. Arrow designations same as Fig. 1).

Proc. Fla. State Hort. Soc. 99: 1986. 197 6/25 7/1 7/8 7/15 7/21 7/28 8/1 8/8 8/15 8/21 8/28 9/1 9/8 9/12 Picking Date

Fig. 4. pH maturity profile of selected Florida wine grape cultivars (Arrow designations same as Fig. 1). differences were not well reflected in the finished wines. stabilization is accompanied by TA close to the after crush In order to obtain a uniform alcohol content around 12% analysis and lower pH values for bunch grapes. In mus all musts were chaptalized to 21° B with sucrose and overly cadines pressing extracts considerable acid without much acid musts (TA> 0.9%) were ameliorated to 0.9% TA with accompanying pH decrease. Fermentation results in 21° Brix syrup. As a consequence of these must adjust further TA increase and pH drop for low acid wines and ments, triangle tests of color-masked wines revealed no a decrease in both TA and pH for high acid (>0.8%) mus significant difference within any of the 4 cultivars as a cadines. These generalizations hold for other cultivars and function of maturity. In general, darker wines (more yel maturity extremes. Table 4 summarizes these trends which low whites and deeper reds) are associated with later are independant of maturity, although degree of ripeness maturity. However, this trend was not clear from the ab- sorbance data. Both white and red wine phenols increased with grape maturity, but these changes apparently did not Table 1. Coefficient of determination (R2) for 100 berry samples, maturity date and composition. influence wine flavor. In the subsequent 1984 study all musts were chaptalized to 21° B, but high acidity was not Cultivar Picking Date vs: adjusted. Nevertheless, wine analyses again demonstrated Treatment remarkably similar composition, independent of maturity (Tables 2 and 3). In this case judges did detect a significant Titratable difference between early and late 'Welder' and early and acidity (TA) g Sugar/ Brix late 'Noble'. These harvests were 21 and 18 days apart, Brix pH (%) berry vs/TA respectively, but wine compositions were not notably dif ferent, except for phenols, as was the case in most maturity Stover extremes. No attempt was made to translate these detecta Hand press 0.95 0.93 0.94 0.92 0.90 ble differences into preferences. The late 'Welder' had a Blended 0.95.... 0.96 0.98 0.92 Conquistador 1 more floral character and pronounced muscadine aroma, Hand Press 0.93 0.17 0.52 0.74 0.62 whereas the late 'Noble' was heavier in tannins. Blended 0.95 0.76 0.97 0.90 In both seasons grape composition was not nearly as Conquistador 2 maturity dependant as the 1984 replicated 100 berry sam Hand press 0.94 0.95 0.96 0.90 0.94 0.97 0.97 0.98 ples and the wines reflected the interaction of vineyard Blended 0.94 Welder location with the masking effects of must adjustments, fer Hand Press 0.99 0.94 0.98 0.98 0.97 mentation and cold stabilization. High acidity is self limit Blended 0.99 0.91 0.96 0.95 ing in both grape species. TA increases from crushing to Noble 0.98 0.97 pressing, particularily with hot pressing or extensive Hand Press 0.99 0.95 0.92 Blended 0.99 0.97 0.91 0.95 pomace contact time where it approximately doubles. Cold

198 Proc. Fla. State Hort. Soc. 99: 1986. Table 2. Bunch grape and wine composition and maturity date.

Stover Conquistador

Picking Date 7/07/83 7/13/83 7/26/83 7/02/84 7/09/84 7/20/84 7/19/83 7/26/83 8/04/83 7/12/84 7/17/84

After crush Brix: 13.7 16.8 18.4 14.9 16.5 18.0 16.7 16.5 18.0 16.6 18.4 pH: 3.0 3.1 3.3 3.2 3.4 3.3 3.5 3.4 3.7 3.5 3.7 % TA: 0.78 0.57 0.56 0.75 0.58 0.65 0.41 0.90 0.38 0.41 0.45 After press Brix: 13.6 16.8 18.0 15.6 16.4 18.0 16.5 16.6 17.6 9.6 8.0 pH: 3.0 3.3 3.5 3.1 3.3 3.4 3.4 3.5 3.7 3.2 3.4 %TA: 1.16 0^82 0.68 0.93 0.70 0.75 1.28 1.26 1.05 1.03 1.04 Must Brix: 21.2 21.3 21.2 21.0 21.0 21.2 20.6 21.0 20.8 pH: 3.2 3.3 3.4 3.1 3.3 3.4 3.4 3.5 3.6 %TA: 0.89 0.80 0.68 0.93 0.70 0.75 0.89 0.93 0.89 Wine pH: 2.7 2.9 3.1 2.9 3.0 3.2 3.1 3.1 3.3 3.4 3.6 %TA: 0.76 0.59 0.58 0.68 0.63 0.65 0.76 0.76 0.68 0.74 0.77 ETOH: 12.6 11.6 12.0 12.7 12.3 12.2 12.6 11.9 10.7 11.2 11.1 Ext: 1.5 1.6 1.6 1.3 1.5 1.8 1.9 1.8 2.2 1.9 2.0 Phenols (mg/L): 110 240 723 291 324 560 2200 2331 2992 1979 2785 Color (Abs) 420nm: 0.06 0.08 0.07 0.07 0.07 0.09 0.39 0.38 0.43 0.37 0.35 520nm: 0.78 0.65 0.74 0.22 0.22

Table 3. Muscadine grape and wine composition and maturity date.

Welder Noble

Picking date 8/12/83 8/19/83 8/06/84 8/10/84 8/27/84 8/18/83 8/25/83 9/02/83 8/09/84 8/21/84 8/27/84

After crush Brix: 13.6 16.8 13.0 16.5 16.2 13.3 15.4 15.4 15.4 14.6 15.8 pH: 2.8 3.1 3.1 3.1 3.6 3.10 3.4 3.0 3.2 3.4 3.4 %TA: 0.59 0.39 0.47 0.36 0.27 0.45 0.34 0.93 0.33 0.17 0.18 After press Brix: 13.4 16.9 12.8 16.0 16.2 13.4 15.4 16.2 15.4 16.6 16.4 pH: 3.0 3.1 3.0 3.3 3.6 3.3 3.4 3.2 3.3 3.3 3.3 %TA: 0.70 0.50 0.53 0^40 0.29 0.86 0.74 1.07 0.77 0.65 0.68 Must Brix: 21.0 20.6 20.9 21.2 21.2 20.9 20.8 20.7 pH: 3.0 3.1 3.0 3.3 3.6 3.3 3.4 3.3 %TA: 0.70 0.49 0.52 0.40 0.29 0.86 0.74 0.90 Wine pH: 2.8 2.9 3.2 3.2 3.3 2.8 2.9 2.9 3.0 3.1 3.0 %TA: 0.83 0.62 0.73 0.75 0.74 0.74 0.57 0.68 0.65 0.59 0.65 ETOH. 12.1 12.4 12.7 11.7 12.1 11.4 11.4 10.6 11.1 11.4 11.2 EXT: 2.1 1.6 1.6 1.5 1.4 1.7 1.6 2.0 1.6 1.6 1.5 Phenols (mg/L): 305 386 335 595 606 2101 2199 3520 1221 830 865 Color (Abs) 420nm: 0.14 0.13 0.07 0.11 0.12 • 0.16 0.09 0.24 0.24 0.16 0.16 520nm: 0.29 0.34 0.39 0.12 0.08 0.08 and pressing regime profoundly influence the magnitude which increase during pressing, fermentation and cellar of these changes. For example, it is not uncommon for a treatments, increasing from 0.2 to 0.5% with a correspond muscadine measuring at crush 0.25% TA and 3.8 pH to ing pH decrease of 0.1 to 0.4 units. Hot pressing or ex produce a wine of 0.65% TA and 3.3 pH. These changes tended pomace contact time can reverse these phenomena. are associated with neither acetobacter activity nor malo For example, a hot pressed high acid must can lose TA lactic fermentation. while a cold pressed low acid must from the same picking This central tendency is operative with TA and to a less will increase in TA during fermentation. Other features extent pH. At early maturity cold stabilization affects a such as total phenols and must/wine color increase with decrease of 0.1 to 0.4% to a wine TA of 0.5 to 0.8%. This maturity and juice extraction severity. drop is accompanied by a pH decrease of 0.1 to 0.3 units. The 25 wines produced during this study were all typ At mid-maturity little TA change takes place from must to ical of the variety and of acceptable quality. Differences wine while pH drops 0.1 to 0.2 units. Overmature bunch attributable to grape maturity which seemed clear in grapes are rarely below 0.5% TA or above pH 3.6 and evaluating identified samples (subjectively) were not evi result in wines of 0.5 to 0.6% TA and 3.4 to 3.5 pH. Mus dent in objective tastings. Nevertheless, it can be concluded cadines, on the other hand, show very low TA at crushing that bunch grapes, due to their high early season acidity

Proc. Fla. State Hort. Soc. 99: 1986. 199 Table 4. Composition trends from grape to wine for Florida hybrid and Literature Cited muscadine grape (B = bunch, M = muscadine). 1. Al-Kaisy, A. M., A. G.Sachde, H. A. Ghalib, and S. M. Hamel. 1981. Titratable Total Physical and chemical changes during ripening of some grape vari- Brix acidity pH phenols eies grown in Basrah. Amer. J. Enol. Vitic. 32:268. 2. Amerine, M. A., and C. S. Ough. 1974. Methods for Analysis of must Initial Compositional Analyses on Grapes Performed After Crushing and wines. John Wiley & Sons, New York. 3. Amerine, M. A., and C. S. Ough. 1980. Methods for Analysis of Must After and Wines. John Wiley & Sons, New York. Pressing Unchanged Variable t t t t 4. Amerine. M. A., and E. B. Roessler. 1958. Field testing of grape maturity. Hilgardia 28(4):93. B M B M 5. Amerine, M. A., and E. B. Roessler. 1976. Wines: Their sensory Must Adjusted Unchanged7 Unchanged Unchanged evaluation. W. H. Freeman and Company, San Francisco, Ca. to 21° brix 6. Bates, R.P., D. Mills, J. A. Mortensen, and J. A. Cornell. 1980. Prefer- Wine Fermented mentation treatments affecting the quality of muscadine grape wines. to dryness Amer. J. Enol. Vitic. 31:136. HI1 t t 7. Bates, R. P., J. A. Mortensen, and T. E. Crocker. 1980. Florida grapes: The next decade. Proc. Fla. Stste Hort. Soc. 93:120. B M B M M B M B M 8. Carroll, D. E., and J. E. Marcy. 1982. Chemical and physical changes during maturation of muscadine grapes (). Amer. J. 'For must TA > 0.8%. Enol. Vitic. 33:168. yUnless diluted by amelioration. 9. Catalina, M. C, R. Romero, and R. Sarmiento. 1982. Metabolic changes in fruit of Vitis vinifera Var. Palomino during ripening in the and ease of extraction, should be harvested at mid or mod Jerez de la Frontera Zone (Cadiz). Anal. Edafol. Agrobiol. 41:1503. 10. Flora. L. F. 1978. Influence of heat, cultivar and maturity on the erately late season. Whereas, muscadines, because of acid anthocyanidin—3,5—diglucosides of muscadine grapes. J. Food Sci. reduction during ripening, less readily extractable acid 46:1819. (particularly by an immediate press) and pronounced mus 11. Flora, L. F., and R. P. Lane. 1979. Effects of ripeness and harvest cadine character when overmature should be picked at date on several physical and compositional factors of Cowart mus early or midseason ripeness. The stage of maturity can be cadine grapes. Amer. J. Enol. Vitic. 30:241. 12. Kluba, R. M., L. R. Mattick, and L. R. Hackler. 1978. Changes in the determined by a carefully chosen 100 berry samples from free and total amino acid composition of several Vitis Labruscana representative vines. Harvest should be limited to the pH grape varieties during maturation. Amer. J. Enol. Vitic. 29:102. range of 3.0 to 3.5 as reflected by pH analysis of hand 13. Long, Z. R. 1984. Monitoring sugar per berry. Practical Winery 5:53. pressed berries, if a light press, or blended samples for 14. Pirie, A. J. C, and M. G. Mullins. 1980. Concentration of phenolics in the skin of grape berries during fruit development and ripening. pomace treatments or a hot press is planned. Provided Amer. J. Enol. Vitic. 31:34. that these pH criteria are met, sugar/berry is a practical 15. Plane R. A., and L. R. Mattick. 1981. Wine acidity: Taste, measure means of following grape ripening, although the wine har ment, control. Amer. Wine Soc. J. 13:2. vest will normally occur 7 to 10 days before s/b values peak.

Proc. Fla. State Hort. Soc. 99:200-202. 1986.

CURRENT STATUS OF THE BLUEBERRY INDUSTRY IN ALACHUA COUNTY AND DELINEATION OF PROBLEM AREAS ASSOCIATED WITH SOIL ACIDITY AS AFFECTED BY HIGH pH IRRIGATION WATER

G. H. Brinen duced to growers. County blueberry acreage increased from Universiy of Florida, IFAS 285 to 489 since 1985 and is projected to increase to 702 by Alachua County Extension Service 1987. Early raobbiteye blueberry ( Vaccinium ashei) cultivars Gainesville, FL 32609 'Climax', 'Beckyblue', 'Aliceblue' and 'Bonia' as well as 'Sharpblue' highbush blueberry ( V. corymbosum) account for S. A. BlENERT AND T. E. CROCKER over half of the acreage planted and almost all of the pro Universiy of Florida, IFAS jected increase. The majority of plantings are less than 5 acres Fruit Crops Department with fruit marketed primarily as pick-your-own. However, Gainesville, FL 32611 nearly all increased acreage was a result of expansion by larger-scale growers who marketed primarily through com Additional index words. Vaccinium ashei, Vaccinium corrym- mercial channels. bosum, pick-your-own. The first plantings of improved blueberry culivars in Absract. Soil pH in Alachua County blueberry plantings was Florida were established in Alachua County in 1961. By surveyed in the spring of 1986 with a portable pH meter and 1973 most of Florida's 100 acres were located in Alachua it was found that 10 out of 35 growers had plantings with County. Plantings continued to increase but were small- pH higher than the recommended range of 4.0 to 5.2. Of scale aond marketed on a pick-your-own (PYO) basis di these, one had increased soil pH as a result of irrigating with rectly to consumers. a drip system. The others had planted in higher pH soils. The In 1983 one area grower sold early blueberries to use of tensiometers for irrigation management was intro- northern markets and received nearly 10 times the then-

200 Proc. Fla. State Hort. Soc: 99: 1986.