Impact of fermentation rate changes on potential hydrogen sulfide concentrations in wine.
Butzke, C. E.; Seung Kook Park; Journal of Microbiology and Biotechnology 2011, 21 (5) 519–524
The correlation between the alcoholic fermentation rate, measured as CO2 evolution, and the rate of H2S formation during wine production was investigated using Saccharomyces cerevisiae strain UCD522 Montrachet and S. bayanus strain UCD819. Both rates and the resulting peaks in the fermenter headspace H2S concn. were directly affected by yeast-assimilable nitrogen compounds in the grape juice.
A series of model fermentations was conducted in temp.-controlled, stirred fermenters using a complex model grape juice containing defined concn. of ammonium ions and/or amino acids. The fermentation rate was measured indirectly from the loss of weight of the fermenter; H2S concn. was quantitatively trapped in real time using a pre-calibrated H2S detection tube which was inserted into a fermenter gas relief port. Evolution rates for CO2 and H2S as well as the relative ratios between them were calculated.
The results confirm that total sulfide formation was strongly yeast strain-dependent, and high concn. of yeast-assimilable nitrogen did not necessarily protect against elevated H2S formation.
High initial concn. of ammonium ions via addition of diammonium phosphate caused a higher evolution of H2S when compared with that of a non-supplemented but non-deficient grape juice. It was observed that the excess availability of the yeast-assimilable amino acid arginine could result in a more sustained CO2 production rate throughout the wine fermentation.
The contribution of yeast-assimilable amino acids from conventional commercial nutrient preparations for yeast to the lowering of the H2S formation was marginal.
(We recommend that you consult the full text of this article)
Published on 07/24/2012