The production of low-alcohol wines by sequential semi-anaerobic must fermentation

Abstract

Nowadays, consumers go towards products that provide food security and nutritional richness, consumption of highly alcoholic beverages not complying with these health-related requirements. This study aimed to obtain low-alcohol wines by performing sequential alcoholic fermentation of grape must (Muscat Ottonel). Thus, 11 commercial yeast strains (10 Saccharomyces cerevisiae and 1 Torulaspora delbrueckii) were preliminarily tested in anaerobic and semi-anaerobic conditions. Based on laboratory tests, grape must fermentation was sequentially initiated in semi-anaerobic conditions (loose cotton plugs; intermittent homogenization), with the T. delbrueckii strain (106 CFU/mL) and the addition of preliminarily selected S. cerevisiae strains (104 CFU/mL), to the consumption of 50% of the sugars in the must, to complete the fermentation. By applying this technology, dry wines were obtained with an alcohol content lower by up to 1.10% vol., but with a lower concentration of volatile terpenes, due to additional must oxidation. Also, semianaerobiosis enhanced glycerol synthesis by yeasts (< 35%), with a positive impact on the sensory characteristics of the wine.