Evaluation of Isolated Yeasts from Grapes of Pinto Bandeira Region, Bento Gonçalves (RS) in relation to Production of H2S and Fermentation Rate

Abstract

The H2S production by yeasts is a frequent problem during the wine making process. Hydrogen sulfide is a gas that produces the characteristic smell of rotten eggs. Therefore, it is important to select Saccharomyces cerevisiae strains that do not liberate H2S during wine fermentation resulting in off-flavor in wine. The goal of this work was to evaluate the yeasts isolated from the cultivars Cabernet Franc, Tannat and Ancellotta from the Pinto Bandeira Region, Bento Gonçalves (RS) in relation to the evolution of H2S and their fermentation skill. Lead (II) acetate paper was used to detect the production of hydrogen sulfide by 120 yeast strains. The fermentation ability of these strains was measured by gravimetry. All yeast strains with strong fermentation capacity did not produce H2S, representing 13.3%. Only one of these strains produced H2S in relatively small quantities in two of the three test tubes. High H2S formation was found in 35.8%of strains. These strains were also characterized by low fermentation capacity. Only 16 strains have showed potential to elaborate wines without off-flavour provoked by H2S.