Use of Non-Saccharomyces Yeast to Enhance the Acidity of Wines Produced in a Warm Climate Region: Effect on Wine Composition

One of the most notable effects of climate change, especially in warm regions, is the decrease in acidity (i.e., increase in pH) of wines and a reduction in their aromatic profile. To address this issue, must from a white grape variety with low acidity were inoculated with two non-Saccharomyces yeasts (Lachancea thermotolerans and Torulaspora delbrueckii) to enhance the acidity of the resulting wines. Basic oenological variables and major volatile compounds and polyols of the wines were analyzed, and the results were compared with those obtained through a Saccharomyces cerevisiae strain. Through multiple regression analysis, we found relations between the production of lactic acid to compounds involved in yeast metabolism and redox balance, including glycerol, acetic acid, isobutanol, isoamyl alcohols, and 2-phenylethanol. By means of principal component analysis, we obtained three components that explain more than 89% of the observed variability. The first component differentiates wines produced by L. thermotolerans; the second differentiates wines obtained by S. cerevisiae from those obtained by T. delbrueckii; and the third component is related to the temperature of fermentation. Organoleptic wines produced with S. cerevisiae were the best valuated, but taste was a highlight of the wines produced with L. thermotolerans due to possessing the best acidity.