How a Wine Becomes Corked
A corked wine is not a wine that has tiny particles of cork floating around in the glass. Rather, corked wine is a wine that has become contaminated with cork taint.
Cork taint is not the taste of a cork. Rather it is the presence of a chemical compound called TCA (2,4,6 - trichloroanisole) and /or TBA (2,4,6 - tribromoanisole) in the wine that generates the 'corky' taste. Traditionally the cork was the 'vehicle' through which the TCA compound reached the wine. This is how the term 'corked' originated.
TCA is formed when natural fungi (of which many reside in cork) come in contact with certain chlorides found in bleaches and other winery sanitation / sterilization products. In the past chloride products were widely used to sanitize both cork and winery equipment. TBA is formed when natural fungi come in contact with bronophenols found in certain pesticide and wood preservative products, also commonly used by wineries. If a winery uses TCA infected corks, the wine becomes tainted with the smell and taste of TCA.
However, we now also know that cork is not the only delivery vehicle for TCA. Oak barrels, wooden palates, or other wood fixtures found in wineries are also susceptible to TCA and TBA contamination that can then find its way into the wine.
If let loose TCA or TBA can contaminate not just a single batch of corks (and wine) but an entire cellar or winery.
The Taste and Small of Corked Wine
While unpleasant to taste, cork taint is not in any way harmful to humans. Corked wines smell and taste of damp, soggy, wet or rotten cardboard. Cork taint dulls the fruit in a wine, renders it lackluster, and cuts the finish.
The obviousness of the corked smell and taste depends both on the extent of the taint, as well as the wine drinker's sensitivity to it (aka your cork taste threshold). The longer the tainted wine sits in your glass and aerates, the more pronounced the corky smell and taste.
Since the discovery (only as recent as the early 1990s) of the cause of cork taint, most wineries have totally eliminated the use of chlorine-based clearing products and implemented stricter QA/QC procedure to minimize the risk of infected corks as well as minimize the possibility of TCA or TBA forming in the winery itself.
For more detail see a previous post on corked wines.
Mary Gorman-McAdams, MW (Master of Wine), is a New York based wine educator, freelance writer and consultant. In 2012 she was honored as a Dame Chevalier de L'Ordre des Coteaux de Champagne.
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