Effect of different strains of Saccharomyces cerevisiae on volatiles produced in Sonoma Valley wines (California)

Flavor and aroma, which are sensed by tasted buds and the olfactory apparatus, respectively, are the major elements of wine that enhance its enjoyment. Each factor is important to the economic value of the final wine product. Flavor and aroma components are contributed by both the grape variety and the yeast strain used for fermentation of the grape must. The classes of volatile flavor components include but are not limited to alcohols, esters, fatty acids and monoterpenes. This four-part study used gas chromatography/mass spectrometry to investigate the volatile components produced in wine fermented by a number of Saccharomyces cerevisiae strains in Napa Gamay, Petite Sirah and Semillon grapes, and in wine produced by fermentation of Chardonnay grapes with added orange, peach, banana, cantaloupe, or pear fruit juices or coffee. The major volatile components in the Napa Gamay wine for all the four yeast types were 3-methyl 1-butanol, phenylethyl alcohol, ethanone, methyl hexanol, ethyl hexanoate, 1-hexanol, butanediol,butaneoic acid esters, decanoic acid esters, and octanoic and decanoic acids. The variances in yeast types resulted in minor differences. MI 16 and Fermirouge yeasts were better suited to fermentation of Napa Gamay must. The major volatile components in Petite Sirah wine were 2-methyl 1propanol, 3-methyl 1-butanol, ethyl ester of propionic acid, acetic acid, diethyl ester of butanedioic acid, hexanoic acid, and methyl ester of butanedioic acid. The variances in yeast types produced flavor differences in the wines. BM45, NI, A350 and A796 are yeasts of choice for red wines. They are ester enhancing and allow the berry notes to come through. The major volatile components in Symphony wine were methyl esters of propanol and butanol, ethyl esters of hexanoic, propanoic and octanoic acids, and 2,3-butanediol, and linalyl propanoate were present. S6U and PdM are preferred yeasts for Symphony wines. Native yeast produced the highest intensity of floral notes. Addition of juice from other fruits to Chardonnay grape must was to accentuate the fruit aromas in the Chardonnay must. All wines exhibited the blended notes, but not the strong flavor compounds for peach and orange wines.