Ever sit down, pour yourself a glass of wine and have it smell reminiscent of a wet newspaper or moldy basement? Or swirled a glass of wine and noticed it smelled muted, or like nothing at all? If so, chances are your wine was cork tainted, or more commonly, “corked.”

Cork taint is a contaminant in wine caused by musty aroma compounds. The most common culprit is 2,4,6-trichloroanisole (TCA). While some wine flaws, such as brettanomyces and volatile acidity, can be subjective as to whether they hurt or enhance a wine, cork taint is universally considered a flaw at any detectable level.

The cause of cork taint

TCA is formed in tree bark when fungi, mold or certain bacteria come into contact with a group of fungicides and insecticides, collectively referred to as halophenols. These were widely used during the 1950–1980s and remain in the soil. Fungi have a defense mechanism that chemically alters these compounds, rendering them harmless to the organism but creating TCA in the process.

Many producers make cork for their wine closures out of tree bark and, unfortunately, they don’t always know if parts of the bark were contaminated with fungicides or insecticides. If they were, their resulting corks would damage any wine they touch.