Studies with Controlled Fermentations. XI. Fermentation Temperature Effects on Acidity and pH

Abstract

Measurements were made to determine the factors causing the increased titratable acidity and lower pH in wines fermented at a middle fermentation temperature (21° C) compared with a lower (10° C) or higher (33° C) one. Succinic acid was the greatest contributor. Malic acid may also contribute. The effect of the greater yeast growth at 21°C than at the other two temperatures is increased enzyme activity and yeast incorporation of greater amounts of the buffering materials, phosphates, amino acids, etc.) and of potassium. The combination of these effecfs is indicated as the cause of changes in the titratable acidity and the pH. Fruit maturity in the range studied has little effect on these variations.