No Sulfur Winemaking in Cabernet Franc (2017)

This study examines the effect of producing wine with and without sulfur dioxide. Cabernet Franc grapes were harvested and processed into 3 separate T Bins. During crush, one treatment received 25ppm sulfur dioxide (control), the second did not receive any sulfur dioxide but instead was protected at crush with Zymaflore Egide, and the third did not receive any sulfur dioxide but instead received Tan Rouge and Stab Micro M during crushing and followed an Enartis no sulfur winemaking protocol. After processing, all wines were inoculated with ES488. One-third through fermentation the Enartis treatment received additions of Pro Tinto and Tan Color. Both no sulfur treatments were inoculated with ML Silver after pressing. At the end of fermentation, the control wine was stabilized with sulfur dioxide, the no sulfur wine received Stab Micro, and the Enartis protocol received additions of Surli Round, Tan SLI, and Stab Micro M. Wine chemistry is similar between treatments, except that no sulfur winemaking resulted in slightly lower TA. Both no sulfur winemaking wines had higher levels of acetic acid bacteria, lactic acid bacteria, and Pediococcus. Color intensity was higher due to a lack of sulfite bleaching. Overall, Cabernet Franc produced with sulfur dioxide tended to have higher perceived Acidity. Other differences between wines were not easy to distinguish with the descriptors used in this study, but the no sulfur wine and the wine with sulfur dioxide may have had slightly higher Overall Aromatic Intensity and Fruit Intensity. The wine made with sulfur dioxide tended to be most preferred, followed by the wine without sulfur dioxide. Conclusions are difficult to draw at this point. Many more studies are needed on no sulfur winemaking in red wines and its impact on sensory qualities. Additionally, more studies are needed to examine how aging is affected by no sulfur winemaking.

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The Impact of Yeast Fining on Wine Quality Prior to Bottling (Enartis, Laffort) (2017)

This study examines the impact of different yeast fining techniques on finished wine quality. A 2017 red wine blend (75% Cabernet Franc, 25% Petit Verdot) was blended into tank in early February. Then, on February 8 the wine was split into four analogous neutral barrels, and the barrels either received no treatment (control), a BM45 yeast addition at 1g/L, a Surli Velvet (Enartis) addition at 0.05g/L, or an Oenolees (Laffort) addition at 0.4g/L. The barrels were stirred on the date of addition and a week later. The wine was pulled for analysis and bottle samples on March 15. There were no differences in wine chemistry and color. For the descriptive analysis, there were no strong trends for the descriptors used in this study. There was a slight tendency for the BM45 treatment to have higher Fruit Intensity, Overall Aromatic Intensity, and Body and lower Herbaceous/Green character. Oenolees had a slight tendency for lower Fruit Intensity and Bitterness. Surli Velvet had a slight tendency towards higher Herbaceous/Green character and Astringency. Many of these differences were not very pronounced, however, and many judges commented that differences were slight. All wines were equally preferred, more or less. Some judges remarked that the BM45 treatment seemed to have a larger effect on the mouthfeel than the rest. More studies are needed in order to better quantify the impacts of these treatments on wine flavor and aroma quality.

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Enhancing Color Stability of Norton with Different Enological Fermentation Tannin (2017)

This study examines the impact of adding different kinds of exogenous tannin prior to fermentation in Norton grape must. Norton grapes were harvested on the same day and destemmed into four T bins. The T bins then received the following treatments: 1) No tannin addition (control), 2) Tan Color (Enartis) addition at 180g/ton followed by Pro Tinto addition (150g/ton) partway through fermentation (mostly condensed tannins), 3) FT Rouge (ScottLabs) addition at 60g/hL (hydrolysable tannin), and 4) a series of BSG product additions: UVA V-Tan at 30g/hL, Premium Limousin at 15g/hL, and Premium Color at 15g/hL (mix of condensed and hydrolysable tannins). All other treatments between wines were equal. After approximately two weeks, wine was pressed off. The BSG wine and the FT Rouge wine had slightly slower fermentations. Wines had slightly differing alcohol contents (slightly higher when using condensed tannin, and slightly lower when using hydrolysable tannin), but otherwise no major chemistry differences were seen. No color differences can be seen. The addition of these products may have slightly lowered caftaric acid and increased epicatechin and gallic acid, and these increases were more correlated to products containing condensed tannin. No major tannin or anthocyanin differences could be seen. For the descriptive analysis, there were no strong trends for the descriptors used in this study. There were slight trends for the control to have lower Fruit Intensity, Astringency, and Body. The wines made with BSG products tended to have higher Fruit Intensity, Overall Aromatic Intensity (along with FT Rouge in this regard), Bitterness, Astringency, and Body. The Pro Tinto/Tan Color and FT Rouge treatments were relatively similar and often fell in-between the Control and BSG products, except for FT Rouge with Overall Aromatic Intensity (where it was higher) and for Pro Tinto/Tan Color with Herbaceous/Green quality. In general, there was a preference for the wine produced with BSG products; however, judges thought that the wines were all fairly similar. In the future, more studies should be performed with these products on different grape varieties.

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The Effect of Adding Tannat Skins and Exogenous Tannin to Chambourcin Fermentations (2016)

This study examines the impact that different sources of fermentation tannins will have on the sensory and phenolic qualities of Chambourcin wine. Chambourcin picked at the same time from the same block were crushed and destemmed into four fermentation bins, each with 1.5 tons of grapes. One bin was a control with no exogenous tannin added; the second bind received oak chips and fermentation tannins (Color Max and FT Rouge); the third bin received 75 pounds of Tannat skins; and the fourth bin received oak chips, fermentation tannins, and Tannat skins. All other treatments between lots were the same. In general, adding oak and tannat skins lowered color and phenolic attributes, except that tannin was slightly increased. Adding these compounds seemed to increase catechin and epicatechin. Adding Tannat skins and oak chips together increased catechin and epicatechin and slightly increased color intensity. Descriptors were mixed, and not too many differences could be seen between wines with the descriptors used in this study. In general, judges tended to prefer the Control wine and the wine made with Tannat Skins, Oak Chips, and Tannin added. This study suggests that the effects of adding different sources of tannin are not additive but instead are complex and difficult to predict.

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The Effect of Oak Adjuncts vs Hungarian Oak Barrels in Chambourcin Aging (2016)

This study examines the impact of aging in new Hungarian oak barrels vs aging in flex tank with Hungarian oak Fans on the chemical and sensory profiles of Chambourcin. Chambourcin wine was split into these vessels with the corresponding treatment. Due to the differences between aging in barrel and flex tank, the wine in flex tank required higher additions of sulfur dioxide. Not many phenolic or chemical differences exist between wines, except the wine aged in flex tank showed higher levels of anythocyanins. Judges found the wines were found to be significantly different (p<0.05), but there were no major preferences for one treatment over the other. There was a slight trend for the flex tank wine to show more Oak Character and less Fruit Intensity. Overall, flex tanks show promise in wine aging, but more work needs to be done to address oxygen ingress and headspace issues, as well as fine-tuning the use of oak adjuncts.

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The Effect of Tannin and Oak Addition on Merlot (2016)

This study examines the impact of adding either VR Supra (Laffort) or both VR Supra and untoasted oak chips on the sensory and chemical qualities of Merlot. Merlot was harvested on the same day from the same block and processed identically into three separate T Bins, one of which was a control, one of which received VR Supra, and one of which received both VR Supra and untoasted French oak chips. All other treatments were the same between groups.  No major differences could be seen in wine chemistry. Color was not impacted much, but the treatments lowered anthocyanins. Adding tannin and adding oak chips increased tannin. The differences between treatments, however, were not that great. Overall, conflicting results were found for the two tastings this project was poured at. At the Shenandoah tasting (May 3), most judges preferred the wine with both Oak Chips and VR Supra, whereas on May 17 that was the least preferred. Oak chips with VR Supra tended to increase Astringency and Bitterness, but this was a weak tendency. These results suggest that these wines could be tailored to meet the demands of different consumer groups. However, the number of judges in these studies were small, and in the future more work should be done on these wines. Additionally, this wine was unusually high in alcohol and extraction due to the vintage, and more of a difference with these treatments may be more observable in different vintages.

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Effects of Adding Hydrolyzable vs Condensed Tannin during Red Wine Fermentation (2016)

This study examines the impact of adding different sources of exogenous tannin to fermenters during Merlot processing. The treatments were set up as follows: 1) Control, 2) FT Rouge (ScottLabs) at 30g/hL, 3) FT Rouge (ScottLabs) at 50g/hL, 4) Tanéthyl Effe (AEB) at 10g/hL, and 5) Oenotan Selection (Esvin) at 10g/hL. All treatments were the same, except that the treatment with FT Rouge at 50g/hL was inoculated with a different yeast from the rest. This wine was therefore not tasted at sensory sessions. No major wine differences could be seen between treatments. The tannin varied with their effect on color intensity: some increased intensity slightly whereas others slightly decreased it. Anthocyanin, in general, was slightly lowered by tannin addition. Tannin content was relatively unaffected, except for FT Rouge 50, which experienced a large increase in tannin. The differences from FT Rouge 50, however, may have been due to the yeast strain used, and does not indicate necessarily that the increase in tannin addition had the effects. Overall, no major preferences could be seen for any treatment, except that the Tan Ethyl Effe was often least preferred. There may have been large changes in wine sensory qualities in bottle over time, as the wines seemed to taste different at the different tastings. This could confound any attempt to compare wines across tastings. This study suggests that exogenous tannin can have impacts on final wine chemistry and sensory qualities, and this may be largely impacted by yeast strain selection as well. In the future, more studies examining the combined impact of exogenous tannin addition with yeast strain selection should be performed.

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The Effect of Different Sources of Lees and Lees Products on Aging Cabernet Franc Wine (2016)

This study examines the impact of adding different sources of lees to aging Cabernet Franc wine. Cabernet Franc wine was split into 5 barrels with the following treatments: 1) no lees addition, 2) 2 pints of Chardonnay lees added, 3) 2 pints of Viognier Lees added, 4) Laffort Autolees added, and 5) AEB Batonnage Elevage added. The wines were stirred once every two weeks until taken for sampling (in February). Wine chemistry did not differ between treatments. The sulfide profile did not differ at the limit of detection of the laboratory analyses. All treatments slightly lowered color intensity and increased hue, except for the AEB Batonnage treatment, which increased color intensity and decreased hue. In the first tasting, the Control and the Laffort Autolees treatment strongly increased Fruit Intensity, but this was not replicated at the second tasting. There were weaker tendencies between tastings, however. Lees which originated from wine (Viognier and Chardonnay Lees) appeared to have a consistent impact on the aroma of the wines, whereas lees which originated from products had less impact on wine aroma. An exception would be the AEB Battonage Plus treatment, which appeared to increase Herbaceous/Green qualities. The AEB lees tended to have the largest impact on Astringency. No major preference trends could be seen. These results were very mixed, likely due in part to the complexity of the project. This project produced interesting results, and more work on the impact of lees management in red wines should be done before drawing hard conclusions about these different lees sources. Stylistic possibilities of adding aromatic white wine lees to red wine should also be considered in future studies.

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Color and Tannin Extraction and Stabilization in Red Winemaking (ARC) (2016)

This study examines the impact of different tannin addition practices on the color and tannin profiles of Merlot wine. Merlot was harvested from the same block and split into three separate fermentation vessels. One vessel received no tannin or oak chip additions, a second vessel received VR Supra and Lafase HE Grand Cru at processing, and VR Color during fermentation (ARC-Laffort Protocol), and a third treatment received Lafase HE Grand Cru and mini chips bois frais oak chips at processing. All other treatments between wines were equal. Wine chemistry between treatments were the same, except that the control tended to have slightly lower TA. Both treatments increased color intensity and tannin, with the Laffort-ARC protocol having the greatest impact. The treatments slightly increased catechin and gallic acid. The treatments tended to slightly lower anthocyanins, but increased polymeric pigment. No strong trends could be seen for the descriptors used in this study. There was a slight tendency for the control to have higher Fruit Intensity and lower Astringency. The Oak Chips + Grand Cru had a slight tendency to increase Body, Bitterness, and Overall Aromatic Intensity. However, these were weak trends. In general, the ARC-Laffort Protocol Treatment was the least preferred. Several judges described these wines as having slightly oxidized characteristics, and as such these sensory results may not be very representative. 

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The Effect of Bactiless on Microbial Stability in Petit Verdot (2016)

This study examines the impact of Bactiless (ScottLabs) on the chemical, microbial, and sensory profiles of two Petit Verdot wines, one of which was not tasted. Petit Verdot wine was racked into two separate barrels for each wine, and allowed to undergo natural malolactic conversion. After malolactic conversion, one barrel from each wine received a sulfur dioxide addition of 6.6g/hL, whereas the other barrel from each wine received 4.4g/hL sulfur dioxide and 50g/hL Bactiless. After 10 days both barrels were racked and returned. Bactiless seemed to lower cell counts for Pediococcus sp, acetic acid bacteria, and Oenococcus oeni. The results varied between wines, however. Other microbes were not strongly impacted by the treatment, but in many cases the cell count may have been too low to be impacted by the treatment. The wines were not significantly different from triangle testing. No major descriptive trends could be seen in this study.

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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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Granular Oak Additions to Cabernet Franc Must (2016)

This study examined the effects of adding Xtrachêne Medium Toasted French granular oak to must at crush on the sensory and phenolic qualities of Cabernet Franc. Cabernet Franc was harvested from the same block, processed on the same day but kept separate, and one lot received 4 pounds per ton Xtrachêne Medium Toasted French granular oak whereas the other remained as a control. All other treatments between lots were the same. Wines made with granular oak exhibited greater hue and less color intensity. This shift in intensity may be due to the lowered levels of quercetin and anthocyanins in the wine produced with granular oak. Overall, there appeared to be a weak, but significant difference, between wines. No major preference trends could be seen, except for perhaps a weak preference for the control. No strong trends could be seen with descriptive analysis, except that on the second tasting most flavor attributes were lowered by the granular oak treatment. Due to the prevalence of this practice in Virginia, and the inconclusiveness of the results, more work should be performed on the impact of granular oak on wines.

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The Effect of Enzyme, Cap Management, and Tannin on Phenolics in Merlot (2016)

This study examined the impact of 5 winemaking techniques on the phenolic composition of Merlot. The treatments were as follows: 1) Control, 2) Stomping grapes during a delestage (otherwise identical to control), 3) Lafase Grand Cru (Laffort) at crush, 4) VR Supra (Laffort) at crush, and 5) Both Lafase Grand Cru and VR Supra at crush. All other treatments were the same between wines. All wines had a delestage operation performed at 2 Brix, where stomping occurred for the stomping treatment. There were no major chemical differences between wines. Stomping had very little effect on phenolic chemistry. VR Supra and Grand Cru alone increased color, but when combined color was lowered (corresponding to lower anthocyanins). No other impacts on phenolic qualities could be observed, except tannin was increased and gallic acid decreased in the wine treated with VR Supra. The sensory impact of the VR supra treatment cannot be adequately assessed due to it being an outlier. Overall, the treatments tended to slightly increase Fruit Intensity and Body relative to the Control. The stomped wine tended to be the most preferred wines for all but the May 3 Tasting. Grand Cru + VR Supra also tended to be regarded fairly highly. The Control wine tended to be the least preferred. These results were not very strong, however, and more studies on the impacts of these treatments on the chemical and sensory qualities of wine should be performed. Additionally, more work should be done to examine the impact of these treatments on wine during aging.

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The Effect Tannin Addition on the Sensory Qualities of Chambourcin Port-Style Wine (2016)

This study examined the impact of adding increasing levels of Querplus (oak tannin from Laffort) to Chambourcin Port-style wine on its sensory characteristics. The treatments for this study were no addition, 50ppm addition, 100ppm addition, and 150ppm addition (5g/hL, 10g/hL, and 15g/hL, respectively). All other treatments between wines were kept the same. Because of sugar and ethanol differences between the control and treatment wines (due to mixing effects), the control wine was not tasted. Barrels were not identical between treatments, but 10-year-old barrels were used for each treatment. Adding Querplus did not affect wine chemistry or phenolics. Overall, higher amounts of Querplus were preferred by judges. 150ppm had a slight tendency to increase the perception of Sweetness, and 100ppm tended to increase the perception of Alcohol and Body. Astringency was not very affected by the treatments. None of these impacts were very pronounced, however. More work is needed on the interaction of tannin, ethanol, and sugar in Port-style wines.

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The Effect of Different Products on Merlot Color Stability (2014)

One Merlot wine was made using a mixture of ScottLabs Color Pro, Tannin VR Supra (Laffort), and French oak chips.  The other wine was made with a mixture of Zym Color Plus (Enartis), Tan Fermcolor (Enartis), and Tan Color (Enartis).  Both experimental wines were meant to mimic similar enzymatic and tannin additions.  There were no chemical differences between the wines, and sensory testing was not performed in this project.  No resources to measure color or phenolic content were available for this project.

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