Sulfury/Yeasty Characteristics in Fermented Beverages
Gotta beer or wine that has a sulfuric aroma? Tastes like rotten eggs, burnt rubber, garlic, meaty, shrimp-like or just yeasty? The culprit is sulfur. Sulfur production is a by product of yeast metabolism. It is not uncommon for yeast to produce hydrogen sulfide which smells like rotten eggs during fermentation. This natural sulfur production will dissipate by the end of fermentation. A vitamin deficient wort or must can increase the hydrogen sulfide production to the point it spill over into the finished product.
Compounds responsible for sulfur production originate from sulfur-containing amino acids, certain yeast strains and bacteria as well as yeast autolysis. If your wine has the aroma of a struck match this is usually the result of the over use of anti-oxidants. Rare in beer, but common in wine and cider is the over use of metabisulfite or campden tablets.
High levels of sulfur can be formed by rapid temperature changes during fermentation, poor oxygenation at pitching, bacterial spoilage and water contamination. Keep your yeast happy and sulfur produced by the yeast won't end up in your finished product. Sulfur is more often detected in lagers than ales. These lower levels can be formed by racking off the sediment before lagering or cold pitching lager. A healthy active primary fermentation scrubs out the gaseous sulfur compounds.