Final Report June 2023

Principal Investigator: Hailan Piao, Washington State University, Richland

Telephone: 509-372-7665

Cooperators: Thomas Henick-Kling and Tom Collins, Washington State University, Richland

Summary: This three-year project studied how wine yeast and malolactic bacteria influence the expression of smoke taint in wine. Smoke-taint compounds, released during fermentation and aging, are largely linked to sugars, forming glycosides. Wine yeast and bacteria possess glycosides enzymes capable of breaking these glycosides, liberating active aroma compounds. The goal was to identify yeast and malolactic bacteria strains that could reduce undesirable aromas in smoke-exposed wine.

Full-scale wine fermentations were conducted on three commercial yeast strains (EC1118, 58WS, GRE) and three malolactic bacteria strains (Lalvin31, Beta, and Alpha) that showed potential for glycosidase activity. Overall, the three malolactic bacteria strains demonstrated higher efficiency in 58WS and GRE fermented wines, and were less effective in EC1118 fermented wine. The study emphasized the complexity of glycosidic activity in wine fermentation, influenced by both yeast and bacteria strains.

Enology // Yeast //