Evaluating Canadian yeast strains for novel new-make spirit applications

Whisky is an alcoholic beverage derived from fermented grain mash that is distilled into 'new make spirit' before maturing in barrels. While most research on whisky innovation has focused on raw materials or maturation, yeast strain selection remains a relatively underexplored avenue for product diversification. Here, we evaluated yeast diversity for whisky production by screening 110 strains sourced from Canadian vineyards for maltose utilization followed by assessing 29 candidate strains in malt extract fermentations. Seven strains representing distinct genetic backgrounds were advanced to pilot-scale fermentations, including a commercial whisky control strain of Saccharomyces cerevisiae, four other S. cerevisiae strains, one Torulaspora delbrueckii strain, and one Saccharomyces uvarum strain isolated from British Columbia wine fermentations. Fermentation performance was assessed via high performance liquid chromatography, and volatile organic compounds in new make spirits were profiled using headspace solid-phase microextraction-gas chromatography-mass spectrometry. All strains completed fermentation except T. delbrueckii, despite undergoing sequential inoculation with a commercial whisky strain. Fermentations with non-S. cerevisiae yeast strains contained elevated levels of glycerol and organic acids. Volatile organic compounds analysis identified 43 compounds, revealing strain-dependent aroma diversity. Notably, S. uvarum P01E08 was enriched in 2-phenylethyl octanoate, phenylethyl alcohol, and phenylethyl acetate. These findings highlight diverse regional yeast selection as a viable strategy to expand whisky sensory diversity.