mercaptans : A class of unpleasant smelling chemical substances containing sulfur. They have aromas of cabbage, dirty socks, rubber and the like, and when found in wine are considered a major fault.
Mercaptans: An unpleasant, rubbery smell of old sulfur; encountered mainly in very old white wines.
mercaptans, wine fault popular with Australian tasters. A skunky smell results from yeast reacting with the lees. It can be cured by assiduous racking.
Mercaptans - Foul-smelling compound derived from a problem with hydrogen sulphide, which gives a smell of onions, garlic, burnt rubber or stale cabbage.
Metallic - An almost bitter, tinny or inky, hard finishing flavour of metals in reds.
MERCAPTANS
An unpleasant, rubbery smell of sulfur. This is mainly encountered in very old white wines.
[edit] Mercaptans
ethyl mercaptan
Mercaptans (thiols) are produced in wine by the reaction of hydrogen sulfide with other wine components such as ethanol or sulfur containing amino acids, such as methionine.
mercaptans...
Can be formed when alcohol reacts with hydrogen sulphide - the "rubbery", "old sulphur" or "bad eggs" smells encountered in over-reduced (very de-oxygenated) wines or very old white wines that are past their best.
Remember,H2S (volatile) à mono-mercaptans (becoming bound) à poly-mercaptans (bound), so deal with the problem as soon as it is detected.
These compounds can be considered "volatile" like aldehydes, ethyl acetate, ester, fatty acids, fusel oils, hydrogen sulfide, ketones and mercaptans) or "non-volatile" like glycerol, acetic acid, and succinic acid.
If not corrected, the wine is ruined as the gas is transformed into mercaptans, with a skunky odor, and then disulfides, with a sewage smell.
mercaptansWine spoilage caused by overuse of sulfur. The resulting wine smells of garlic. mesoclimateThis term describes the climate of a small area, typically an individual vineyard or hillside.
 See also: Mercaptan, Fermentation, Grape, Wine, Off
  
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