The aim of this experiment was to determine measurable differences of grape quality by utilizing Heat Blast technology used to treat wine grapes. A block of Petit Manseng was divided into two separate sections. One section was treated with heat blast delivery to the canopy and fruiting zones using an Agrothermal Systems XT heat system. The other section was not treated with this technology. The treatment block was treated 1 to 4 times per month depending on stage of growth, with the treatment regime starting around veraison. The majority of treatments were near veraison. Chemical spray regimes were the same between treatments. All other vineyard and winemaking treatments between grapes were equal. Acidity and potassium was slightly lower in the heat-treated grapes. Quercetin and tannin slightly increased in grapes, whereas catechin slightly decreased. Wine chemistry was not very much affected except for lower malic acid levels in the heat treatment. The tannin content of wine with heat treatment was slightly higher for most compounds. Overall, these wines were not found to be significantly different. There was a very slight tendency for the Control to have higher Tropical Fruit intensity, Fruit Intensity, and Body. No major preference trends could be seen between wines. In the future, more studies should be performed with Agrothermal heat treatment and its impacts on fruit chemistry. These studies should look into multiple grape varieties, as well as closely monitor disease progression. The use of Agrothermal heat treatment in conjunction with different vineyard spray regimes should be investigated as well. Although more studies are needed to confirm this, these preliminary results suggest that heat treatment may be a beneficial tool for East Coast viticulture.
This study examines the impact of leaf pulling on one vs both sides of the vine in Petit Verdot. Petit Verdot vines (clone 400, planted 2012, 9x4 spacing, ESVC/CW index of 2.4) from the same block were split so that all vines received leaf pulling on the east side at flowering, and one portion of the vineyard received leaf pulling on the west side as well at veraison. Grapes were harvested on the same date, and all winemaking practices were identical between treatments. Must was inoculated with D80, Enzyme CX was added, punched down twice per day until fermentation was complete, and then switched to one punchdown per day during extended maceration (25 days maceration time, total). Juice chemistry was similar between treatments, although leaf pulling on one side resulted in higher alcohol content and lower acidity. Color and anthocyanin were not much impacted by treatments. Seed tannin indices (catechin, epicatechin, and gallic acid) may have been slightly lowered with leaf pulling on both sides. Tannin may have slightly decreased by this treatment, as well. The sensory results suggest that the two wines were significantly different. No strong trends could be seen for the descriptors used in this study, although Acidity seemed to be lower in the one sided leaf pulling wine. No major preference trends could be seen between treatments. This study should continue to be performed over multiple years, in different regions, as well as on different grape varieties.
This study examines the impact of timed Nitrogen and Sulfur sprays on the sensory and chemical attributes of Sauvignon Blanc. A mix of Nitrogen and Sulfur sprayed at 20% veraison and at 50% veraison were applied to 2 out of four segments of a vineyard block. The other segments were unsprayed. The grapes were harvested and processed identically. After racking off of gross lees, the lees were harvested, combined, and centrifuged to create a centrifugate juice (a mix of the lees from the control and sprayed grapes). No major chemical differences were found between the control and treated juice and wines, except that pH was slightly higher. The sprayed wine had a slightly higher level of 3-MH. However, the wine made from the combined lees centrifugate had the highest level of 3-MH and lower levels of 3-mercaptohexylacetate. Additionally, this wine had a longer lag phase during fermentation compared to the other two. Judges were generally able to distinguish between the unsprayed and sprayed treatments, and there was a tendency for the sprayed treatment to be preferred and the centrifuged treatment to be least preferred. The sprayed wine had slight tendencies to have higher Overall Aromatic Intensity, Herbaceous/Green character, and Varietal Character. There were slight trends for the centrifuged wine to have lower Tropical Fruit and Varietal Character than the other treatments, and higher Herbaceous/Green character. These tendencies were all very weak, however.
This study examines the impact of removing the 4 most basal leaves from Cabernet Sauvignon vines at 30% bloom. One section of a vineyard block was not leafed at bloom, while another section underwent this leafing treatment. Both treatments received leaf-pulling at veraison. All other vineyard and fermentation practices were the same. Leaf removal at bloom appeared to slightly reduce berry weight, cluster weight, Brix, and yield. Grape phenolics and TA were slightly increased by bloom leaf removal. Wine produced with leaf removal at bloom had lower ethanol, color intensity, and tannin. Judges did not find the wines to be significantly different, and there were no strong preference trends for either wine. Early leaf removal may have had a very weak tendency to increase Overall Aromatic Intensity. The lack of differences are likely due in part to the particular vintage (weather events may have equalized the treatments) and in part due to vegetative growth reducing the effectiveness of the bloom leaf removal. More studies need to be performed in this area in order to draw more conclusions.
This study examines the impact of LalVigne Mature Foliar Spray (ScottLabs) on ripeness and the chemical and sensory qualities of the South side of Merlot vines planted East-West. Every other row of a block of Merlot was sprayed at 5% veraison and 10 days later following the LalVigne spray protocol with a tunnel recycle sprayer, allowing for a treatment of sprayed Merlot and a treatment of unsprayed Merlot. Both treatments were harvested only from the South side of the vine (afternoon side) and processed identically and on the same day, but kept separate. All other treatments between projects were identical. The LalVigne spray slightly decreased tannins and anthocyanins in the grape berries. Caffeic acid was higher in wine from grapes treated with LalVigne. Tannin was also increased in wine from grapes sprayed with LalVigne, but anthocyanins were decreased. Triangle sensory testing revealed no significant differences between wines, and there was no strong preference for either wine. The sprayed wines tended to exhibit greater Fruit Intensity, but this was not a strong tendency.
This study examines the impact of LalVigne Mature Foliar Spray (ScottLabs) on ripeness and the chemical and sensory qualities of the North side of Merlot vines planted East-West. Every other row of a block of Merlot was sprayed at 5% veraison and 10 days later following the LalVigne spray protocol with a tunnel recycle sprayer, allowing for a treatment of sprayed Merlot and a treatment of unsprayed Merlot. Both treatments were harvested only from the North side of the vine (morning side) and processed identically and on the same day, but kept separate. All other treatments between projects were identical. The LalVigne spray slightly increased tannins and anthocyanins in the grape berries, but lowered cluster weight (although not berry weight). Anthocyanins were decreased in the wine from grapes treated with the LalVigne spray. Triangle sensory testing found significant differences in the wines (p<0.05), although there was not much of a preference for one wine over the other. No major descriptive sensory trends can be seen.
This study examines the impact of LalVigne Foliar Spray (ScottLabs) on ripeness and the chemical and sensory qualities of Cabernet Franc. Every other row of a block of Cabernet Franc was sprayed at 5% veraison and 10 days later following the LalVigne spray protocol with a tunnel recycle sprayer, allowing for a treatment of sprayed Cabernet Franc and a treatment of unsprayed Cabernet Franc. Both treatments were harvested and processed identically and on the same day, but kept separate. All other treatments between projects were identical. The LalVigne spray slightly increased phenolics in the grape berries, but lowered cluster weight (although not berry weight). The LalVigne spray also increased YAN in juice. No chemical or phenolic parameters were very different in the wine. For the triangle test, of 20 people who answered, 12 people chose the correct wine (60%), showing a statistically significant difference between wines (p<0.05). These wines were voted to have an average degree difference of 4.2 (out of 10) among those who correctly identified it, suggesting that the wines were moderately different. In general, people who answered correctly had no preference for one treatment over another. There were no strong trends with regard to the descriptors used in this study.
This study examines the impact of a desiccation spray on the chemical and sensory profiles of Chambourcin grapes and wine. One block of Chambourcin was divided so that one section of fruit was sprayed with a potassium bicarbonate desiccant, and another section was not sprayed. The desiccated fruit was sprayed at the beginning of veraison and then weekly for a total of four sprays over four weeks. The fruit was harvested and processed on the same day, and all treatments between the fruit were identical. The desiccation treatment slightly concentrated berry components, although not many differences were found in wine. The desiccation treatment, however, lowered the color intensity and slightly lowered the tannin and anthocyanin content in the wine. Other parameters were not greatly affected. At one tasting, the wines were found to be significantly different (p<0.05), and in general there was a preference for the wine made without desiccation. At another tasting, there was no significant difference between wines, and no major preference trends. More studies on desiccation across vintages would be beneficial to further elucidate the impact of these treatments in Virginia.
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.
This study examines the impact that LalVigne Foliar Spray (ScottLabs) has on the ripeness of Chambourcin grapes. Lalvigne was sprayed at 5% veraison and then 7-9 days later on a 2 acre parcel of Chambourcin at the recommended rate. Control and treatment grapes from the same block were harvested and processed on the same day, fermented separately as 1.5 ton lots in T Bins, and all other treatments between fermentations were kept the same. A third treatment was also added, were 75 pounds of Tannat skins were added to LalVigne-treated grapes at the beginning of fermentation. Although ripening kinetics between each treatment were similar (data not shown), anecdotally, the sprayed berries exhibited more color development. Juice from LalVigne-treated grapes exhibited higher nitrogen numbers (except lower ammonia). Wine produced with Tannat skins added had lower alcohol and pH (58% increase in proton concentration). In general, grapes treated with LalVigne showed increased color intensity and increased amounts of phenolic compounds. The sprayed grapes showed a large increase in Malvidin glucoside but a slightly lower count of monomeric and total anthocyanins. Tannat skins added to the LalVigne sprayed wine showed a smaller increase in color intensity, a larger increase in catechin, epicatechin, gallic acid, and tannin, and a decrease in anthocyanin content. For the triangle test, of 21 people who answered, 9 people chose the correct wine (43%), suggesting the wines were not significantly different. In general, people who answered correctly had a slight preference for the sprayed wine, but this preference was very weak. Descriptive analysis did not show many trends between wines. The control tended to have slightly lower Overall Aromatic Intensity to the sprayed wines, and the wine with Tannat skins seemed to have higher Fruit Intensity. The LalVigne spray wines tended to have slightly higher Herbaceous/Green scores, except for the wine with Tannat added.
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.
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.
This experiment was designed to determine whether there is an increased balance of flavor and structure in Chardonnay when it is harvested based on acid and chapitalized, or whether it is harvested on Brix and acidulated. The chemical differences between wines were not great. A significant sensory difference was found between wines, with more people preferring the wine picked based on acidity.
Petit Manseng with East/West planting had leaf pulling on the north and south exposure at the end of June. The remainder of the block had leaf pull on only the northern exposure, also at the end of June. No chemical differences were found between the grapes from this project. No sensory data is available.
For one half of a single block of Petit Verdot, leaf pulling was done on the east side of the vines. For the other half of the block, leaf pulling was done on both the east and west sides. The leaf pulling was done approximately one month prior to harvest. There were very little chemical differences between the wines, and no significant sensory differences were found.
In a single block of Pinot Gris, one half of clusters were cut in half following the completion of veraison. The berries that had undergone cluster halving exhibited more sugar accumulation, but had less tartaric acid. The wines, however, were not very different. No significant sensory differences were found between wines.