Performance of Selected Uruguayan Native Yeasts for Tannat Wine Production at Pilot Scale
The wine industry is increasing the demand for indigenous yeasts adapted to the terroir to produce unique wines that reflect the distinctive characteristics of each region. In our group, we have identified and characterized 60 native yeast strains isolated from a vineyard in Maldonado-Uruguay, in which three strains stood out: Saccharomyces cerevisiae T193FS, Saturnispora diversa T191FS, and Starmerella bacillaris T193MS. Their oenological potential was evaluated at a semi-pilot scale in Tannat must vinification in the wine cellar to have a more precise and representative evaluation of the final product. Fermentations were carried out with these strains as pure starter cultures in 200L fermentation tanks, compared to the commercial reference strain. The three native strains consumed 98% of the must sugars with good ethanol production (between 14-16%) and low volatile acidity, suggesting that alcoholic fermentation generates dry wines with an appropriate alcohol level and low residual sugar. Pilot-scale fermentation trials demonstrated the strong fructophilic character of St. bacillaris, with high glycerol production (11%) and lower ethanol yield, which could be of particular interest, for example, in producing low-alcohol wines. Wines produced with these native strains, evaluated by a panel of expert winemakers, stood out for presenting greater fruity notes compared to the reference strain, especially St. bacillaris T193MS, with descriptors associated with plum, raisins, and candied fruit. These findings correlated with an increase in the concentration of volatile compounds determined by GC-MS, where a significant increase in the content of esters, nor isoprenoids, and terpenes compounds was found in the vinification produced with the St. bacillaris T193MS compared to the other studied strains.
Issue: ICGWS 2023