hydrogen sulfide (H2S) [HY-druh-jihn SUHL-fyd]
hydrogen sulfide is the result of yeast combining with various forms of sulfur. It produces an undesirable, rotten-egg smell in wine. Eventually, H2S in wine transforms into mercaptans (a skunky odor) and disulfides (a sewage smell), both of which ruin a wine.
The New Wine Lovers Companion, 2nd Edition, by Ron Herbst and Sharon Tyler Herbst. Copyright © (1) 2003, 1995 by Ron Herbst and Sharon Tyler Herbst. Reprinted by arrangement with Barron's Educational Series, Inc.