Grant: Engage Grants Program

Primary fermentation of wine occurs when grape sugars are converted to ethanol by the action of yeast, mostcommonly by Saccharomyces cerevisiae. There are two types of fermentations used to produce wine:spontaneous and inoculated. In spontaneous fermentation, the must is exposed to the resident yeast population,whereas in inoculated fermentation, a commercially available S. cerevisiae yeast starter is used as an inoculant.We recently found that yeast fermenting wine must, both in inoculated and spontaneous fermentations, areusually a mixture of commercial yeasts. These tend to reflect yeasts that have previously been used as inoculumat the winery. The problems we are addressing are that Tantalus Vineyards (TV): 1) does not know the yeastsfermenting their wines; and 2) is spending a relatively high amount on commercial yeasts. Knowing the yeastsfermenting the wine will aid TV in future yeast-purchasing decisions and will provide the winemaker moreconfidence in using spontaneous fermentation. By knowing the yeast fermenting the wine will lead tointelligent winemaking decisions and an increase in wine quality. These actions will increase the efficiency bywhich yeasts are used, resulting in cost reductions. The objectives of the collaboration between UBC Okanaganand TV are as follows: 1) to foster the development of a new research partnerships between UBC Okanaganand TV; 2) to determine the yeast present at 4 different stages from spontaneous and inoculated fermentationsof two varietals of grapes; 3) by using these findings, the two partners will determine ways by which costsaving can be achieved. Wine must will be sampled at TV in October 2013 from Pinot Noir and Chardonnayfermentations. Three inoculated and three spontaneous tanks will be sampled from 4 stages. Serial dilutionswill be performed and aliquots will be plated onto Yeast Extract Peptone Dextrose agar (YEPD). DNA will beextracted from twenty-four colonies and identified using 6 microsatellite loci. DNA fingerprints will becompared to a strain database in order to determine the strains present. Non-Saccharomyces spp. will beidentified by amplifying DNA and subsequently sequencing it.