No Sulfur Winemaking in Chardonnay (2017)

This study examines the effect of fermenting wine with and without sulfur dioxide. Chardonnay grapes were harvested and pressed into 3 separate tanks. At pressing, one treatment received 3g/hL sulfur dioxide (control), and the other did not receive any sulfur dioxide, and the third did not receive any sulfur dioxide and received Stab Micro M and Tan Blanc at pressing and followed an Enartis no sulfur winemaking protocol. After settling, the juices were racked into barrel and inoculated with CY 3079. The Enartis wine received additions of Claril SP during settling. After completion of malolactic conversion, the control wine was stabilized with sulfur dioxide, and the Enartis treatment had Stab SLI, Tan SLI, and Stab Micro added at the end of malolactic conversion. Both barrels with the Enartis treatment fermented slower than the rest. No major chemistry differences were found between wines except for slightly lower lactic acid in the Enartis wine. The no sulfur wine had slightly higher levels of Lactic Acid Bacteria, slightly less O. oeni, and slightly less S. cerevisiae. The Enartis wine had slightly more S. cerevisiae, and slightly higher diacetyl. In general, judges were able to distinguish between the wine made with and without sulfur dioxide. This may have been due to a perceptible difference in diacetyl between these two wines, likely due to diacetyl binding by sulfur dioxide in the wine produced with sulfur dioxide. The no sulfur wine treatment may have had slight oxidation (but not in a negative respect), and the Enartis no sulfur wine may have had a slight bitterness (although this was not examined statistically). A perceived bitterness in the Enartis wine may be due to the use of sacrificial tannin. Preferences were not strong, but there seemed to be a preference for the wine made with sulfur dioxide, and then perhaps followed by the wine made without sulfur dioxide. However, many more studies are needed to further qualify how no sulfur winemaking impacts wine sensory qualities. Additionally, more studies need to be performed to determine how no sulfur wines age over time.

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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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