Alcohol Losses During Fermentation of Grape Juice in Closed fermenters

Abstract

Experiments were performed in closed fermenters both in the laboratory and on a plant scale to estimate alcohol losses, due to entrainment in escaping carbon dioxide, during the fermentation of grape juice. The laboratory fermentation at 80°F (27°C) showed that 0.83% of the total alcohol produced escaped with the carbon dioxide. The plant experiment started with fermenting must of 4.6% alcohol and ended in a 10.6% alcohol wine, with a fermentation temperature range of 85-87°F (29-31°C) and an alcohol loss of 1.17% of the total alcohol produced.

Also discussed in some detail is a method of calculating such alcohol losses, whether due to carbon dioxide entrainment or saturation of air used in mixing or aeration of wine or brandy blends Despite many simplifying assumptions made in the calculations, the results do no differ significantly from the experimental values.

The calculated alcohol losses emphasize the importance of fermentation temperature control: losses at a temperature of 95°F (35°C) are more than double those incurred at 80°F (27°C).