Wine flaws: cork taint

Cork taint is characterized by a corky, musty, damp cellar smell. Every wine-lover has experienced this type of unpleasant odor, without ever associating it with a faulty cork. It's called "wine with a stink".

But it's not just the cork that's responsible for suspect smells and tastes. between 5% and 8% of bottles distributed on the French market are corked. Although agglomerated corks are often to blame, natural and natural colmated corks are also incriminated.

TCA and derivatives responsible for cork taint

The molecule responsible for most corked wines is called TCA (trichloro-anisole). It was identified in the 1980s by a Swiss researcher, Hans Tanner, who showed that cork taint was mainly due to this chlorine molecule, produced by molds nested in the cork. Since then, other molecules have been isolated, chemically very close to TCA, but with different origins, and which also parasitize wines. It's impossible to know which molecule they are when tasting.

The presence of these products gives the wine an unpleasant odor and a corky aroma. The average concentration of TCA in corked wines is 8 nanograms per liter, but the molecule can be detected as early as 5 nanograms per liter, or even 2 or 3 nanograms for a "trained nose", depending on the individual. One gram of TCA can contaminate 266 million bottles!

Cork taint and other similar defects

The cork leaves behind several different types of odor. The natural smell of cork, which can be transmitted to the wine either by cork dust or when the bottle is opened and the cork is pierced. Cork is a micro-porous material that fixes ambient odors incredibly well. As well as the real taste of cork, there are other bad tastes.

Cork captures the various good and bad smells of the environment in which the bottles are stored, and transmits them to the wine. These aromas are similar to, but not the same as, cork tastes. Other bad tastes are due to the use of old barrels, poor bottle washing, the paper used to filter the wines, a grape harvest affected by rot, or cellar hygiene that leaves much to be desired.