Effect of different strains of Saccharomyces cerevisiae on production of volatiles in Napa Gamay wine and Petite Sirah wine.

Napa Gamay grapes were fermented with four different strains of the yeast Saccharomyces cerevisiae (VL1, MI16, Fermirouge, and RA17). Petite Sirah grapes were fermented with seven different strains of the same yeast (BM45, Fermirouge, RA17, NI, CX3079, A350, and A796). Volatile compounds formed in the wines were analyzed by gas chromatography/mass spectrometry. Volatile compounds found in both wines were alcohols, esters, and acids, as well as some miscellaneous compounds. Isoamyl alcohol was the compound found in the highest relative amount with all four yeast strains in the Napa Gamay wines, followed by 2-phenyl ethanol, monoethyl succinate, and hexanoic acid. The relative amounts of isoamyl alcohol ranged from 30.84% (VL1) to 43.28% (RA17). Major volatile compounds found in Petite Sirah wines were isoamyl alcohol, 2-phenyl ethanol, 2-hydroxy ethyl propanoate, monoethyl succinate, and octanoic acid. The several esters, including 2-hydroxyethyl propanoate, may contribute to the fruity flavor of Petite Sirah wines. Overall, the S. cerevisiae yeast strains used to ferment Napa Gamay grapes and Petite Sirah grapes produced the same major components, with certain variations in formation levels.