Fermentation Rates of Grape Juice. III. Effects of Initial Ethyl Alcohol, pH, and Fermentation Temperature

¹ Department of Viticulture and Enology, University of California, Davis.

The effects of initial alcohol on grape juice fermentation have been studied by observing interactions with temperature and pH. Initial alcohol delayed and limited fermentation. At pH 3.0 the effects on the lower initial alcohols were inhibiting, but, as the initial alcohols increased above 4% by volume, adjustments to this pH responded similarly to those at pH 3.5 and 4.0. Fermentation rates were diminished rapidly at 91°F at over 4% initial alcohol. At 70°F, rate response to initial alcohol changes was nearly linear. At 50°F, fermentation rates are affected less drastically by initial alcohol concentrations above 4%. Viable cell count data indicate that the above responses are due mainly to growth-limiting or killing effects on the yeast.

This article has been cited by other articles:

				M. C. Coleman, R. Fish, and D. E. Block Temperature-Dependent Kinetic Model for Nitrogen-Limited Wine Fermentations Appl. Envir. Microbiol., September 15, 2007; 73(18): 5875 - 5884. [Abstract] [Full Text] [PDF]