Combined indigenous yeast strains produced local wine from over ripen Cabernet Sauvignon grape in Xinjiang

Cabernet Sauvignon grape produced in Xinjiang (China) is often overripe, with unusually high sugar content, which impedes utilization. We aimed to establish the optimal combination of indigenous yeast strains to produce a new sweet wine from the overripe grape. Five yeast strains with pronounced enological characteristics were selected from 88 indigenous yeast isolates. Using a series of co-fermentation experiments with different inoculated strategies, we achieved optimal co-fermentation with a combination of strains SC19 and NS68, later identified as Saccharomyces cerevisiae and Pichia kudriavzevii, respectively, simultaneously inoculated in a 1:1 ratio at the early stage of fermentation. The combination was characterized by vigorous fermentation with high resistance to 457.13 g/L sugar and high alcohol yield (16.01% vol). The sweet wine contained 17 aromatic compounds with odor activity value (OAV) ≥ 1 and pronounced sweet fruit, floral, herbaceous, and caramel odors. The co-fermentation has a good potential for utilization of overripe Cabernet Sauvignon grape.