How do you recognize cork taint in sparkling wine?

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Dear Dr. Vinny,
One of our customers refused a bottle of Prosecco because of cork taint. Could you please explain cork taint in sparkling wine?
—Gulfidan O., Izmir, Turkey
Dear Gulfidan,
Cork taint is the most common wine flaw. You may also hear people refer to these tainted wines as “corky” or “corked.” They are usually recognized by their moldy, musty aromas of wet cardboard, damp basement or mixing cement, all of which are caused by the presence of the chemical compound 2,4,6-trichloroanisole, or TCA. TCA is caused by the interaction of mold, chlorine and phenols, which are organic compounds found in plants. Since natural corks are made from the bark of cork oak trees, TCA can originate there. But TCA can also originate in other places, like cardboard cases, wooden barrels or pallets. TCA isn’t harmful, just unpleasant, blocking the olfactory channels that would otherwise allow you to enjoy a wine’s fresh fruit notes.
That musty aroma that indicates the presence of TCA should come across similarly whether the wine in question is red, white, sparkling or sweet.
Hopefully you gave your customer a replacement bottle. If you’re not familiar with what TCA smells like, you should have taken a whiff. Once you’ve smelled it, it’s much easier to identify it.
—Dr. Vinny