Variations in the Percent Ethanol (v/v) per °Brix Conversions of Wines from Different Climatic Regions

Abstract

Ethanol yield per degree Brix has been shown to vary from area to area, and somewhat from year to year (4,5,9). These differences were verified statistically in 1981 and 1982. Two explanations were evident for the variations in the ethanol per °Brix. Grapes that are non-irrigated and slightly shriveled tend not to crush easily. These higher sugared grapes then release sugar during the holding period prior to pressing or, with red grapes, during fermentation. The original must sample will indicate a lower °Brix than the real °Brix of the must later. The other explanation is fruit low in nitrogen grows fewer yeast; hence, less sugar is converted into cellular material, and a higher efficiency of ethanol production results. Dry land vineyards generally have fruit of a lower yeast nutrient content. These observations were verified by analytical data and calculations.