Influence of yeasts of the genus

Traditionally the Serra Gaúcha region, in the state of Rio Grande do Sul, is known as a barn productor of excellent quality wines. The aromatic complexity of wine in general, and white wine in particular, is what is essential to satisfy an increasingly demanding consumer. Among the most used techniques to achieve this purpose is the addition of yeasts of different genres, thus providing a range of aromatic characteristics that are accentuated in it. In this sense, the objective of this work was to evaluate the use of different strains of yeasts in white wines of Riesling Italic variety, made from grapes grown in the Serra Gaúcha region, in the state of Rio Grande do Sul. Based on the results, it was possible to observe that there were no significant differences between the treatments in relation to the variables pH, total acidity and alcoholic degree. However, with respect to the fermentation yield, T3 was the treatment that obtained the best performance, reaching the ideal density (below 1000 g.cm3) in the course of 6 to 7 days, followed by treatments T1 (Saccharomyces cerevisae) and T5 (Levulia pulcherrima) (7 to 8 days), with treatments T2 (Saccharomyces cerevisaecerevisae) and T4 (Torulaspora delbrueckii), which had the lowest performance (9 to 10 days). The T4 treatment was also the one that presented a higher amount of residual sugars, which proves the less activity of this yeast in more alcoholic means. All the yeasts used have a low production of volatile acidity, but the lowest concentration was Saccharomyces cerevisae cerevisae, used in treatment T2 (0.1 gL−1), and the other treatments presented higher concentrations (0, 4 to 0.5 gL−1), although it is still within the parameters considered ideal for obtaining quality white wines. T2 was also the treatment with lower concentrations of glycerol (5.1 g.L−1). This compound is mainly formed by glyceropyruvic fermentation through the metabolism of yeasts at the beginning of alcoholic fermentation, usually being produced by the first 50 grams of fermented sugars, which may indicate a greater activity of this yeast in this fermentation period. In general, we can say that all the yeasts used have the potential to produce quality white wines, since they had good fermentation yields, satisfactory production of alcohol and glycerol, and low production of volatile acidity