Vineyard and winery yeast contribution in spontaneous fermentations of chardonnay must at tinhorn creek vineyard

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Non-Saccharomyces, Saccharomyces spp. other than Saccharomyces cerevisiae, and S. cerevisiae are threegroups of yeasts that are involved in winemaking. Based on results from previous Engage and CRD grants, wefound that spontaneous fermentations, conducted in the Okanagan, are completed primarily by commercial S.cerevisiae strains that the winery has used as an inoculant. In 2015, our group studied Chardonnayfermentations and we surprisingly found that Saccharomyces uvarum, a cryotolerant Saccharomyces yeast, wasable to dominate and complete fermentations that were started at 12C. Both S. uvarum and S. cerevisiaetolerate relatively high SO2 and alcohol concentrations, but S. uvarum can also affect the wine aroma andflavour differently than S. cerevisiae. We do not know whether the identification of S. uvarum from the 2015vintage was an anomaly or whether it will be a consistent trend associated with the Mission Hill Family EstateWinery (MH) or if this trend occurs at other wineries that harvest their grapes in a similar area as does MH. Wewill be repeating the spontaneous fermentations at MH in the 2017 vintage using Chardonnay grapes. Forcomparison purposes, we will conduct the identical experiment at Tinhorn Creek Vineyards (TCV). Thus, theobjectives of this proposal are to: 1) develop a research partnership between UBC Okanagan and TCV; 2) tocompare the Saccharomyces and non-Saccharomyces yeast composition of lab and winery fermentations so asto determine whether the origin of yeasts were from the vineyard, winery or from both; 3) to compare the yeastcomposition in fermentations that differ by having grapes sourced from different vineyards (one close and onefar away from the winery). Our results will provide information to TCV winemakers, helping them in theirselection and management of yeasts, which will help them improve wine quality and reduce costs. Since TCVwill continue to conduct spontaneous fermentations in their Chardonnay varietals and will continue sourcingChardonnay grapes from these two vineyards, knowing the yeast in these fermentation treatments will helpthem in their management decisions.