SIMURG
mercaptan
EN
n.
Wine fault that can be cured by assiduous racking and that presents a kunky smell resulting from yeast reacting with the lees. 1
Volatile sulfur compounds, and specifically mercaptans, are […] largely responsible for the olfactory defect known as ‘reduction’. […] [Mercaptans, also known as thiols, are] a large group of very smelly sulfur compounds. Terms such as cabbagey, rubbery, struck flint or burnt rubber are used as descriptors. If hydrogen sulfide isn’t removed quickly, it can result in mercaptan production. This is a big worry for winemakers.
[…] sulfides present in the wine at bottling necessitate a very small level of oxygen ingress through the closure, otherwise they can become reduced to thiols. Because sulfides are less smelly, it is possible for a wine that is clean at bottling to taste reduced after bottling if the closure doesn’t permit enough oxygen ingress. So the use of a closure, such as cork, which does allow a little oxygen ingress (but not too much) is a necessary concession to the vagaries of sulfur chemistry. Of course, we’d rather not have the sulfides in the wine at all, which would then avoid problems with reduction to mercaptans at a later stage. 2
When a wine is strangely lacking in aroma, low level sulphur compounds should be suspected. The penny test will confirm that suspicion for H2S or mercaptan. Such wines should be considered flawed. 3
UK [məːˈkapt(ə)n] US [mərˈkæpˌtæn] 4
Synonym: thiol 5
< German Mercaptan (W. C. Zeise 1834, in Ann. der Physik u. Chem. 31 378) < mer- (in post-classical Latin mercurius) + captan- (in classical Latin captāns, present participle of captāre to take, seize): Zeise explains the formation as follows ‘Mercaptan (d.h. Corpus mercurium captans).’ 6
Università degli Studi di Genova
revisione di Chiara Barbagianni
1 : «http://www.grapestomper.com/wineglossary.html», (24/11/2011)
2 : «http://www.wineanorak.com/mercaptansinwine.htm», (24/11/2011)
3 : «www.bcawa.ca/winemaking/flaws.htm», (29/07/2008)
4 : «http://www.oed.com/view/Entry/116613?redirectedFrom=mercaptan#eid», (24/11/2011)
5 : «http://chemicalland21.com/industrialchem/solalc/ETHYL%20MERCAPTAN.htm», (24/11/2011)
6 : «http://www.oed.com/view/Entry/116613?redirectedFrom=mercaptan#eid», (24/11/2011)