Synopsis
The wine yeast Saccharomyces cerevisiae (S. cerevisiae) converts grape sugars into ethanol and also contributes organoleptic properties during wine
fermentation. Other non-Saccharomyces yeast species can also impact a wine's sensory profile. S. cerevisiae and other yeast species are increasingly recognized as an important contributor to a wine's regional character, or terroir. We have identified a potentially indigenous population of S. cerevisiae in one Pinot Noir vineyard in British Columbia (BC)'s Okanagan wine region by performing spontaneous fermentation of Pinot Noir grapes and selective plating as a method to enrich for S. cerevisiae species. The Okanagan Valley represents an untapped resource of indigenous wine yeast strains that are of great interest to the BC wine industry. Following our study of one Pinot Noir vineyard, the Measday Lab at the University of British Columbia (UBC) Wine Research Centre (WRC), in collaboration with our industry partner the British Columbia Wine Grape Council (BCWGC), intends to survey S. cerevisiae and other yeast populations in Pinot Noir vineyards of three Okanagan Valley sub-regions. Our objective is to identify indigenous S. cerevisiae populations by spontaneously fermenting Pinot Noir grapes from 13 vineyards in three sub-regions of the Okanagan, explore commercial S. cerevisiae dispersal into the vineyard from wineries, and elucidate differences in Pinot Noir vineyard yeast population structure between the different sub-regions. Our study will be the first to systematically characterize S. cerevisiae populations in different microclimates of a North American wine region and the first to characterize vineyard-associated yeast species across a wine region in Canada. Our long term goal is to discover and characterize a potentially valuable resource of novel indigenous S. cerevisiae strains and other yeasts in Okanagan vineyards that may be used to enhance the region's wine quality and regional character, thereby increasing BC product value and competitiveness in the international wine market.