Troubleshooting Your Wine
The faults and flaws and their analysis and resolution presented below are from my latest book, Modern Home Winemaking, where you can find additional information should you wish to explore these further.
CORK TAINT
DESCRIPTION
Cork taint is a condition where wine has a moldy, musty smell, often described as a damp basement or wet newspaper smell, and which has become devoid of its anterior aromas and flavors. This fault almost always, but not exclusively, occurs in bottled wine under natural-cork closures.
CAUSES
Cork taint is the result of microbial contamination of cork material; it causes a chemical reaction between phenols from lignin degradation (of cork material) and chlorine in the environment or which was used in bleaching natural corks in the manufacturing process. It is often referred to as TCA, short for its molecular name, 2,4,6-trichloroanisole, a powerfully odorant molecule with a detection threshold in the 1–4 ng/L (ppt) range, but which poses no health concerns. It can, however, easily contaminate your winemaking area as wood barrels and pallets and cardboard boxes can harbor these contaminants, which can then infect wine.
ASSESSMENT
This fault can be assessed qualitatively by smell. It is easily detected by wine drinkers who are familiar with the smell of TCA although detection can vary by individual; many only detect TCA at 10 ng/L or more.
REMEDIAL ACTIONS
There is no remedy for a TCA-infected wine; it is best discarded. There is anecdotal evidence that some have had some success in at least reducing the musty smell by pouring wine over plastic wrap made from PVC (polyvinyl chloride) — not LDPE (low-density polyethylene) plastic — although this is believed to scalp other aromas and flavors.
PREVENTIVE ACTIONS
Given that this fault occurs almost exclusively in wines bottled with natural corks, use a TCA-free alternative closure, such as micro-agglomerates or synthetic closures, if you intend to age wine for years. Or you can use bottles with a crown-cap finish if you can source these; you will need a crown-capper to crimp caps on bottles.
Alternatively, consider kegging wine. Wine is protected and “pushed” by inert gas, such as nitrogen or argon; you simply pour as much wine as desired into a carafe for your dinner needs.
And avoid any and all chlorine-based cleaning or sanitizing products in your winemaking area; these are common and high-risk sources of TCA infections. In cellar construction or maintenance, avoid using pressure-treated lumber as these products too are a source of similar contaminants.