TY - JOUR T1 - Effect of Bentonite Treatment of Grape Juice on Yeast Fermentation JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 28 LP - 36 DO - 10.5344/ajev.2002.53.1.28 VL - 53 IS - 1 AU - Kathryn C. Weiss AU - Linda F. Bisson Y1 - 2002/01/01 UR - http://www.ajevonline.org/content/53/1/28.abstract N2 - Fermentation parameters were evaluated in six juices spanning three vintages and three varieties receiving either simple bentonite addition or bentonite fining preinoculation. Bentonite fining of five juices resulted in a statistically significant but minor effect in reduction of the maximum fermentation rate displayed by the yeast. There was no effect on rate if bentonite remained present during fermentation. Minor effects on the length of the lag preceding initiation of rapid sugar consumption were also observed. The parameter most affected by bentonite fining was overall fermentation time, calculated as the time from the end of lag phase to a soluble solids concentration of 0 Brix. Four juices displayed a dramatic increase in overall fermentation time with increasing bentonite addition. The inhibitory effect of bentonite was greater in juices with an initial high sugar content. Bentonite fining did not significantly affect amino acid composition, and micronutrient supplementation did not restore fermentation rate to that of the untreated control. Nutrient addition did shorten overall fermentation time, but the effect was minor. The data suggests that bentonite fining of juice impacts a factor needed to sustain fermentation rate, such as the amount of fatty acids available to the yeast.Acknowledgments: This research was supported by a grant from the American Vineyard Foundation. KCW has received support from the American Society for Enology and Viticulture, Gino Zepponi Memorial Scholarship, the Wine Spectator Scholarship, the Steven S. Scott Research Fellowship, Albert and Pearl Winkler Scholarship, Mario Tribuno Memorial Research Fellowship, Temecula Valley Wine Association, and Jastro-Shields Graduate Research Fellowship. Sophocles Vlassides is thanked for the HPLC determinations. Portions of this research were presented at the 1995 and 2000 Annual Meetings of the American Society for Enology and Viticulture. ER -