Vineyard Sprays to Improve Ripening in Merlot (in collaboration with VT) (2017)

This study examines the impact of different desiccation sprays on the resulting juice and wine chemistry of Merlot. 8 rows of Merlot from the same block were divided into 4 pairs, each pair of rows receiving a different treatment. The following treatments were performed: 1) Control (no spray), 2) RG 1950 spray in collaboration with Dr. Mizuho Nita, where rows were sprayed 4 times weekly, over four weeks, starting from veraison, 3) VT Tech Dehydration spray in collaboration with Dr. Bruce Zoecklein, where rows were treated on the fruit zone at approximately 19 degrees Brix using a 2% solution of methyl esters of fatty acids in a 2% solution of potassium carbonate in water, and 4) Sugar Express (Miller Chemical) Spray (4-10-40 Nitrogen-Phosphate-Potash), where rows were treated on the full canopy at approximately 19 degrees Brix at 10 lbs/acre. All other viticultural and winemaking practices were equal. Grapes were harvested on September 20, after processing musts were inoculated with D21, and each fermentation received a 16 day maceration. The two VT sprays had the greatest impact on Brix and Average Berry weight during ripening. Fluctuations are due to rain events around September 2 and September 6. The VT sprays produced juice with higher Brix, although the Zoecklein spray had higher TA and the RG 1950 had lower TA. Wine chemistry showed higher ethanol for these two sprays, higher TA and tartaric acid for all three sprays, and lower levels of lactic acid. Color intensity was increased by the desiccation sprays. Anthocyanins were slightly lowered for the VT sprays, although polymeric anthocyanin was increased for these sprays. Tannin showed slight increases for these sprays as well. These phenolic differences, however, were not very great.

Overall, the desiccation sprays had a tendency to lower the Herbaceous character of the wines. Overall Aromatic Intensity and Body tended to be increased by the Zoecklein spray, although RG 1950 also had a slight tendency to increase Body. These two sprays also had a slight tendency to increase Fruit Intensity, although this was weak. In general, the control wine was more similar to the Sugar Express treatment, and the two Virginia Tech desiccation sprays were more similar to each other. Preference trends were hard to determine, but the Sugar Express treatment tended to be less preferred. The two Virginia Tech desiccation sprays were perhaps slightly more preferred control when considering that these two wines were fairly similar to each other. These results suggest that desiccation sprays may be a valuable tool in Virginia winemaking, and studies like these merit more rigorous analysis, especially with regard to sensory attributes of the wines. These studies should be continued to be repeated, on multiple varieties over multiple vintages.

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Harvest Decisions Based on Grape Phenolic Development (Enartis) (2017)

This study examines the ability to judge when grapes are harvest-ready by monitoring phenolic development over time. Cabernet Franc grapes began being sampled weekly starting on September 1 for a number of chemical and phenolic parameters. Enartis then made a harvest recommendation for September 22 (First Pick) based on comparing phenolic and chemical profiles over time. This decision was based on declining anthocyanin and phenolic values occurring in the grapes, with a desire to pick while these values were near their peak. The winemaker monitored grapes based on in-house chemistry values, seed coloration, and hang time, and picked another portion of the block on October 4 (Second Pick). Because the chemistry was different between juices, the second pick juice received more tartaric and malic acid additions. All other treatments were the same, except for a possible non-addition of Lafase HE Grand Cru to the second pick must. Wines were pressed off after 18-19 days. Grape ripening tended to follow classic ripening curves, exhibiting increasing Brix and a positive sigmoidal pH ripening curve. Average berry weight and water content peaked and then declined, due to dehydration. Phenolic content tended to peak and decline as well, and this occurred after the berry weight and water content began to decline. The first pick, based on phenolic ripeness, had lower alcohol. The differences in lactic acid may have been due to different malic acid additions between treatments. The first pick wine had slightly higher tannin and anthocyanin and much higher quercetin glycosides, but slightly lower color. However, this wine received Lafase HE Grand Cru, whereas the second pick wine may not have received this enzyme. This may have altered the results in this regard. Overall, sensory analysis suggests that these wines were significantly different. There tended to be a preference for the earlier picked wine, but this preference was tasting-dependent. Descriptive analysis was inconsistent between tastings, and no conclusions can be drawn with regard to this. Due to this inconsistency, this study should be repeated multiple times to help gauge the impact of picking based on phenolic parameters on sensory qualities in wine. Additionally, the use of Lafase HE Grand Cru in one wine and perhaps not in the other could have further confounded these results, suggesting that this study should be repeated. However, the idea behind this technique of monitoring ripening may serve to be a useful guide to picking in Virginia, to harvest while phenolic levels are maximized before they begin to decrease.

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The Effect of Crop Adjustment and Desiccation Spray on Ripeness (2016)

This study examines the impact of different crop adjustment techniques on yield, juice and wine chemistry, phenolic and color profiles, and sensory characteristics of Merlot. The four treatments in this trial were performed in the same vineyard block as follows: two control rows, two rows sprayed with RG 1950 desiccant spray, two rows with clusters dropped at veraison down to one cluster per shoot, and two rows with clusters pinched at approximately 20 Brix. All other treatments, through vinification, were the same. The desiccation spray exhibited faster ripening kinetics and lower average berry weight. At harvest, Brix and pH were not very different, but TA was higher in the treatments. No differences were apparent in wine chemistry. All treatments exhibited increases in color intensity, especially the cluster dropped treatment. In spite of increasing color intensity all treatments lowered anthocyanins. The desiccant treatment slightly increased tannins. The week before harvest, 6 inches of rain fell, which may have reduced the impact of these treatments. Overall, desiccation and crop reduction had a slight tendency to enhance Fruit Intensity. The treatments also tended to enhance Overall Aromatic Intensity. These trends were weak and often conflicted between tastings. There seemed to be a general preference for wines produced from dropped clusters and desiccated clusters, but this varied. The rain event may have reduced the impact of these treatments. This study suggests that crop adjustment techniques have the potential to impact fruit and wine quality in Virginia, but much more studies are needed to fully quantify this impact as well as to account for vintage variation.

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Surround Crop Protectant Trial with Petit Verdot (2014)

Petit Verdot that received heavy leaf pulling was either sprayed or not sprayed with Surround Crop Protectant in the fruiting zone in order to prevent sunburn.  No chemical, phenolic, or sensory differences were found in this study, suggesting that Surround does not negatively impact finished wine quality.  However, this year was a relatively light "sunburn" year at this vineyard, so the true impact of Surround may not have been adequately quantified.

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LalVigne Mature Foliar Spray with Virginia Merlot (2014)

This study examined the chemical and sensory effects of LalVigne Mature Foliar Spray on finished Merlot wine.  There were no chemical differences in the grapes that were harvested in this study; however there were significant sensory differences between the final wines.  People tended to prefer the wine produced without the spray.

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