The Effect of Juice Turbidity on Aroma Development in Aging Sauvignon Blanc (2017)

This study examines the impact of different turbidity levels in Sauvignon blanc juice on aroma development. Sauvignon blanc for this study was all harvested on the same day from the same block at Veritas. The grapes were destemmed and cold soaked at 45°F for 19 hours with 35ppm liquid sulfur dioxide and pressed the following day. Only free run juice was used. After the juice was pressed off Cinn-Free was added at a rate of 1.6ml/hL. The juice was settled for two days and then racked off of juice lees and inoculated with X-5 Yeast. At this point lees were added to two of the barrels to two levels of NTU (65.8 NTU and 195 NTU), while the third barrel kept the naturally occurring NTUs of processing (19 NTU). After fermentation the wine was allowed to settle and then was racked off of fermentation lees before barreling into three identical neutral barrels. At racking the medium and high rates of turbidity were combined, for two total treatments: 1) a low turbidity treatment and 2) a high turbidity treatment. No major differences in wine chemistry resulted from the turbidity differences. Thiol parameters may have slightly increased in the higher turbidity treatment. Overall, winemakers were able to distinguish statistically significant differences between wines (p<0.001). This may have been due to slight turbidity differences present in the glasses. No strong trends could be seen with the descriptors used in this study.

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Sauvignon Blanc Production with Lafazym Arom (2017)

This study examines the use of Lafazym Arom (Laffort) (pectinase and β-glucosidase) additions on the varietal character of Sauvignon blanc wines. Many volatile aroma compounds are glycosylated, resulting in very high solubility and low volatility. Thus, these compounds must be enzymatically cleaved to remove the glucose moiety in order for these aromatic compounds to be sensed. Lafazym Arom is an enzyme which may be able to impact the sensorial attributes of certain grape varieties, particularly terpenic varieties. Sauvignon blanc was harvested, destemmed, and cold soaked for 20 hours, after which grapes were pressed and settled with CinnFree for one day. Juice was racked into stainless steel barrels for fermentation and inoculated with Vin-2000. Different barrels received different rates of addition of Lafazym Arom after fermentation: 1) no Lafazym, 2) 2/ghL (low rate) Lafazym, and 3) 4g/hL (high rate) Lafazym. Barrels were then topped with sulfur dioxide. All other treatments between wines were equal. No differences in wine chemistry are apparent between treatments. Enzyme addition increased 3-mercaptohexanol, perhaps with diminishing returns at larger doses. Overall, wines produced with Lafazym Arom tended to have higher Overall Aromatic Intensity and Thiol Character. Tropical Fruit character also was generally increased with Lafazym Arom. Wines made with Lafazym Arom tended to be more preferred, although differences were present with regard to the rate of Lafazym addition. These results suggest that Lafazym Arom can have a large impact on the aromatic qualities of Sauvignon blanc.

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The Impact of Trellising on Ripening and Quality in Merlot (2017)

Different trellising systems can have a large impact on canopy sun exposure, leaf area:fruit ratios, and yields. Different trellising systems also have different labor requirements for proper management. Determining which trellising system is best for a given site, on a given variety, is therefore very important. This study examines the difference between two training methods – VSP and Scott Henry – on resulting juice and wine quality. Merlot (clone 181) was planted in 2000 and trained as Scott Henry. In 2017, every other row of this block was converted to VSP. All vineyard treatments were identical, with leaf pulling on east side of vine after fruit set. Grapes were harvested on the same day, and all fermentation practices were identical between treatments. There were not many differences in juice and wine chemistry, except for slightly lower tartaric acid in the Scott Henry wine and decreased acidity. Tannin may have been slightly lower in the Scott Henry wine as well. Overall, these wines were not found to be significantly different, but perhaps would have been at more lenient p levels. Descriptive analysis was not completely consistent between tastings. Preferences slightly favored the VSP trellis, but this was not strong. This study should be repeated over multiple years on different grape varieties. More careful attention should be paid to viticultural parameters, such as leaf area to fruit weight ratios, and yield parameters.

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The Impact of Different Leaf Pulling Treatments in Cabernet Franc (in Collaboration with Cain Hickey) (2017)

This study examines the impact of different leaf pulling regimes on ripening in Cabernet Franc. Grapes received either: 1) No leaf pulling, 2) Standard leaf pulling (leaf pulling before mid-June on East side of vine), 3) pre-bloom leaf pulling (May 17, both sides of vine), 4) post fruit-set leaf pulling (June 2, both sides of vine), 5) Mechanical leaf pulling (May 26, post fruit-set, both sides of vine), 6) bagged clusters (July 22). Grapes were harvested on the same day. All other treatments were identical. Mechanical Leaf Pulling and Post-Fruit Set Leaf Pulling had the smallest average berry weight (no data is available for the bagged clusters). Pre-bloom leaf removal saw the greatest increase in average berry weight, but this was not significant when compared with No Leaf Pulling and Post-Fruit Set. Yield per vine was significantly lower on the pre-bloom leaf removal compared to No Leaf Pulling and Post-Fruit Set, but Brix was significantly higher. This yield difference likely resulted from the significantly lower cluster weight in the Pre-Bloom treatment, as well as the lower number of berries per cluster and the lower number of clusters per vine found in the leaf pulling treatments. The Pre-Bloom and Post-Fruit Set treatments spent much more time at critical temperatures between 35-40°C than the No Leaf Pulling treatment, due to greater exposure of the grapes. The Pre-Bloom treatment was overall cooler than the Post-Fruit Set treatment, possibly because of the decreased berries per cluster and thus looser cluster architecture allowing for better air flow and cooling.

Leaf pulling always increased tannin, quercetin, and anthocyanin concentration in grapes, with the greatest concentration of tannin in the Pre-bloom Leaf Removal and anthocyanin and quercetin in the Post-Fruit Set Leaf Removal. Leaf-pulled juice tended to have less malic acid and lower YAN. In general, TA and color was higher in finished wine with leaf pulling, with the greatest increases seen in post-fruit set leaf pulling. Caftaric acid, gallic acid, quercetin, tannin, and anthocyanin were generally increased by leaf pulling, with the most profound differences found in pre-bloom and post-fruit set leaf pulling. Bagged clusters showed much lower color and tartaric acid.

Due to the complexity of this project, the Mechanical Leaf Pulling and Bagged treatments were not tasted. Overall, descriptive results for these wines were inconsistent between tastings. Wines which had received leaf pulling were generally more preferred by judges, with preferences generally being for early leaf pulling regimes. This study should be repeated several times in order to further validate these results. It should also be performed on different grape varieties, at different sites, and on different trellising systems. More rigorous descriptive work should be performed on these projects, as well.

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Central Virginia Cabernet Franc Terroir Investigation (2017)

The purpose of this study is to evaluate the difference in wine quality and chemistry based on vineyard site and winemaking style using Cabernet Franc grapes grown in and around the Monticello Wine Trail appellation. This purpose was achieved through comparing the impact of growing area on wine style (by comparing how wines from different vineyard sites taste when produced by the same winemaker) as well as comparing different winemaking stylistic impacts on grapes from different regions (by tasting grapes from the same region being produced by different winemakers). Three winemakers traded their grapes to each other and fermented each other’s grapes according to their own stylistic practices. The results of this study suggest that winemaking practices are able to substantially impact many of the vineyard effects on wine chemistry. Wines produced at Veritas tended to be positively correlated with Tannin and either negatively correlated to Total Anthocyanin, or not correlated with Anthocyanin (Veritas Winery Veritas Grapes). Wines produced at Early Mountain Vineyards, on the other hand, were generally correlated to Total Anthocyanins and negatively correlated to Tannin. Horton winery tended to produce wines which were in-between the Veritas and Early Mountain wines, in many of these regards. Overall, these results suggest that while vineyard site places some boundaries on the chemical qualities of wine, chemical qualities can be easily driven by winemaking practices. However, vineyard site tended to have the greatest impact on sensory characteristics. Early Mountain grapes tended to have more Herbaceous and Acidic qualities, and Veritas grapes tended to have higher Fruit Intensity and Astringency. Horton grapes tended to have higher Overall Aromatic Intensity. However, winemaking practices were able to alter these sensory characteristics in some cases, so that there was not a simplistic division of vineyard sites into certain flavor profiles. Most parameters were not dominated by either winemaking or vineyard site, but a mixture of both was seen. In the future, many more studies should be performed, with more statistical rigor.

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Sauvignon Blanc Clonal Investigation (2016)

This study examines the clonal differences between Sauvignon Blanc FPS 1, FPS 18, ENTAV 376, and ENTAV 241 planted in the same year in the same vineyard block. Grapes were harvested and pressed on the same day but kept separate, and all treatments between lots were kept the same. Yields were different between some clones, and the FPS clones tended to have higher malic acid and YAN. Clone 241 tended to have lower acidity and higher pH than the other clones, and the opposite trend was observed for FPS 1. Wines produced from FPS 1 and ENTAV 376 had the highest levels of 3-MH. Descriptive analysis found several differences between clones. Wine made with ENTAV 376 was highest in most sensory descriptors, and most people preferred Clone 376. However, these differences may not all be clonal, but could be due to variations between fermentations. As such, this study should be repeated in order to determine if clone 376 is truly much more aromatically intense.

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The Effect of Tan Citrus on Chardonnay (2016)

This study compares Chardonnay wine fermented either with or without the enological tannin Tan Citrus (Enartis) added before primary fermentation. When combined with yeast with β-glycosidic activity, this tannin may increase fruit and floral aromas in wine. The yeast used in this study was CY3079. No major chemical differences were found between wines. The wines were not significantly different. There was a very slight preference for the wine made with Tan Citrus. More work is needed on the enological additive to effectively evaluate its impact.

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The Effect of Toasted and Untoasted Oak Chips and Granular Oak Additions to Red Must (2016)

This study examines the impact of toasted and untoasted granular oak additions to Petit Verdot must. Petit Verdot grapes were sourced identically and processed identically into 4 separate fermentation vessels, one without oak additions, one with untoasted oak chip additions, one with toasted oak chip additions, and one with Xtrachene medium toast French granular oak additions. All other treatments were kept the same between wines. The Xtrachene granular oak exhibited the greatest increase in color intensity, tannin content, and polymeric anthocyanins (suggesting more color stability). Color was only slightly improved by oak chips. Untoasted oak chips and Xtrachene toasted granular oak exhibited an increase in caftaric acid, catechin, epicatechin, and gallic acid. Oak consistently lowered caffeic acid, although the numbers are very small. Anthocyanin extraction was not enhanced by oak, and was even lowered by toasted oak chips. In general, oak saw increases in color, catechin, epicatechin, and tannin, with granular oak resulting in the largest increases. In general, people preferred the control wine. The second-most preferred and least-most preferred wines were made with Granular Oak. No strong trends were found for the descriptors used in this study. The Granular Oak treatment seemed to increase Bitterness, Fruit Intensity, and Astringency more than the other treatments. Toasted Chips appeared to increase Fruit Intensity, along with Granular Oak. However, these tendencies were weak. Wines made with Granular Oak were often described as being oaky or smoky.

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Tan Elegance in Chardonnay (2015)

This study compared the chemical and sensory attributes of Chardonnay with and without the addition of Tan Elegance (Enartis).  The wine with Tan Elegance had lower titratable acidity, but all other chemical attributes were the same.  There was a  significant sensory difference between wines, with a slight preference for the wine without Tan Elegance.

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Chardonnay Juice Fining with Oenolees (2014)

Chardonnay juice was treated with Oenolees (Laffort) partway during fermentation, and the finished wine was compared to Chardonnay from the same pick that had not had Oenolees addition. Although there was no real chemical difference between the wines, there was a significant sensory difference between wines.  No preference or descriptive data was taken.

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Co-Fermenting Cabernet Franc with Viognier (2015)

Two lots of Cabernet Franc harvested from the same block were sorted and processed identically. Prior to fermentation Viognier pomace was added to the trial lot (5-7% by volume). The trial wine had lower phenolic and color attributes, likely due to adsorption of phenolic and color compounds on the Viognier pomace.  Tannin was not much lower, but color was greatly lowered.  There were only slight differences in chemistry.  A sensory difference could be distinguished between the control and the trial, with most people preferring the control.

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Stylistic Goals of Chardonnay Based on Brix or Acidity (2015)

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.

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Cabernet Franc Drying Tunnel (2015)

Cabernet Franc grapes were processed traditionally as well as in a grape drying tunnel in order to desiccate them.  The Cabernet Franc that went through the drying tunnel had a lower alcohol percent, in spite of the desiccation.  The desiccated wine had higher levels of anthocyanins and had higher color intensity.  Although there was no sensory difference between the wines, in general people tended to prefer the desiccated wine.

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