Compositional Factors Affecting Sulfide Formation During Wine

Sixteen samples of grapes from commercial vineyards were fermented during the 1996 harvest studies. These included 1 each of Chardonnay, Cabernet Franc, Sangiovese and Syrah, 4 Merlot and 8 Cabernet Sauvignon samples. Musts were supplemented with diammonium phosphate and a vitamin mixture to avoid deficiencies in these being a cause of sulfide formation. The levels of hydrogen sulfide produced during fermentation were measured by GC using direct headspace sampling and flame photometric detection. The values obtained ranged from 0 to 155.8 ug (mean of 23.6, sd of 25.9). Yeast strain comparisons on 3 musts gave the following sulfide formation results (in ug): Fermevin (mean of 26.1, sd of 27.2), Lavin D254 (mean of 30.2, sd of 37.3), PDM (32.8,sd of 42.3) and Montrachet (mean of 35.6, sd of 44.1) and are not significantly different from each other when tested on multiple juices. The juices were analyzed for individual amino acids, glutathione and sulfate concentrations and these were correlated with the formation of hydrogen sulfide using principal component analysis (PC A). The levels of sulfate, glutathione and free amino nitrogen (FAN) were all positively correlated with higher sulfide production. Studies with one of the juices show the effects of addition of glutathione and separately, sulfate on the increased levels of hydrogen sulfide production.