Evaluation of Zygosaccharomyces bailii to Metabolize Residual Sugar Present in Partially-Fermented Red Wines

An alternative approach to remove residual sugar from red wines using strains of Zygosaccharomyces bailli was studied. Fructose (40 or 60 g/L) and alcohol (13%, 15%, or 17% v/v) were added to a Cabernet Sauvignon wine before inoculation of Z. bailii B2, B6, or W3, or Saccharomyces cerevisiae EC1118. Most yeasts maintained populations ≥106 cfu/mL up to 100 days—the exceptions being W3 and EC1118, which declined to ≤30 cfu/mL in 17% alcohol wines beyond day 75. Wines containing 40 g/L fructose and 13% alcohol achieved dryness (<2 g/L), except those inoculated with B6. At 15% alcohol, B6, W3, and EC1118 consumed large levels of fructose (>80% of the 40 g/L; >50% of the 60 g/L) but limited amounts from wines containing 17% alcohol. Volatile acidities were higher in wines inoculated with strains of Z. bailli compared to S. cerevisiae (0.88 and 0.75 g/L, respectively). Fructose utilization in a partially-fermented Syrah wine varied, with dryness achieved by EC1118 or a mixed culture of B2 and B6. While Z. bailii metabolized residual fructose in wines of varying alcohol content, the use of S. cerevisiae EC1118 was generally as effective and did not produce as much volatile acidity.