Reducing Green Character with Yeast Strains (Enartis) (2017)

This study examines the impact of different yeast strains on green character in Cabernet Franc. Cabernet Franc grapes were harvested and processed on the same day into 3 separate T Bins. Each T Bin received 25ppm sulfur dioxide and were then inoculated with either CSM (ScottLabs), D254 (ScottLabs), or D20 (Enartis). D20 yeast may reduce green character through higher fermentation temperatures blowing off pyrazine (Enartis 2018), therefore this T bin was fermented in the sun. CSM was chosen because it is also marketed as being able to reduce green character (Scott Laboratories 2018), but since it did not specify a higher fermentation temperature, this treatment was not fermented in the sun. Each T Bin was punched down twice per day and pressed on the same day for 9 days of maceration. All other treatments between wines were identical. All yeast strains had similar fermentation kinetics, with D20 perhaps being slightly warmer. Wine chemistry was similar between treatments, except that IBMP was slightly lower in the D20 yeast treatment. There were no strong trends for the descriptors used in this study. There was a slight trend for the CSM wine to have higher Fruit Intensity, and for the CSM and D20 wines to have higher Astringency. There was a slight preference for the D254 wine.

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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 LalVigne Foliar Spray on Chambourcin (2016)

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.

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