Sulfur-Containing Compounds

Abstract

Sulfur, in its various forms, is important to the yeast in protein biosynthesis as well as vitamins and coenzymes. Formation of volatile sulfur compounds plays an important role in sensory properties of wines. These compounds may be variously described as rubbery, onion, garlic, cabbage, kerosene-like, and skunky. The somewhat undefined, but objectionable character arising from interaction of sulfur-containing compounds and wine components is sometimes described as “reductive tone.” Wines exhibiting this property lack (or are deficient in) focused fruit and complexity attributes and are described as “reduced.” Sulfur is available as sulfate (SO ²⁻₄ ), sulfite (SO ²⁻₃ ), amino acids (methionine, cysteine, and cystine), the tripeptide glutathione, as well as the vitamins biotin and thiamine (B₁), and acetyl-CoA and lipoic acid.