Usage of different aerobic non-Saccharomyces yeasts and experimental conditions as a tool for reducing the potential ethanol content in wines

Alcohol reduction in wines is gaining increasing importance due to global warming and the resulting rising amounts of must sugar. During the last years within the microbiological approaches the usage of non-Saccharomyces yeasts became a focus of interest. In this study different non-Saccharomyces yeasts were used to respire in the presence of oxygen the potential alcohol content in grape must. Three different experimental set-ups including five different non-Saccharomyces yeast strains were used and compared. The focus was on improving the temperature, oxygenation and nitrogen addition to improve the sensory quality of the resulting wines. The positive effects of these improvements could be especially seen while looking at the declining isovaleric acid content of one Pichia guilliermondii strain. Most promising was a Metschnikowia pulcherrima strain, whose usage led to an alcohol reduction of 3.8 vol% within 3 days.