Hydrogen sulfide (H2S) is an important contributor to the so-called ‘reductive’ off-flavor present in some wines, with an odor threshold of only 0.9-1.1 μg/L for white wine and 1.6 μg/L for red wine. Even at a level that can’t be detected by a human nose, H2S can impact the wine aroma negatively, masking the fruit, and giving a ‘closed’ sensation. Moreover, the chemical reactivity of H2S can lead to the formation of other negative compounds such as sulphides and mercaptans especially during aging.
Research has shown that all yeasts, indigenous or selected produce H2S and the capacity of the yeast to do so is genetically determined. The wine yeast will also respond differently to different environmental factors, for example, nutritional status of the must, which can impact H2S formation. Continue reading for more in-dept researh on the topic and how to manage H2S in your wine.
WE #7 - H2S production by wine yeast