Did my wine turn bad because the cork was leaking?

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Dear Dr. Vinny,

I just opened a magnum of a 1990 Napa Valley Cabernet. I noticed in the past year that the cork was leaking, and I didn’t think much of it. But when I took the first sip, it totally tasted like vinegar. What happened? How long does it take for a bottle of wine to turn into vinegar?

—Ricardo G., South Padre Island, Texas

Dear Ricardo,

A leaking cork was your first clue that the wine inside might be flawed. A bottle leaks when the cork has been compromised. It could have been from a cork that was faulty to begin with, or one that dried up, or perhaps it was the result of heat, causing the wine inside to expand. It can be a bit of a crapshoot—I’ve had wine from leaky bottles that was perfectly fine. But it’s certainly an indication that something may have gone wrong.

The thing about leaky bottles is that if the wine can leak out, that means that oxygen has a chance to leak in. That extra exposure to oxygen can cause a wine to oxidize and taste tired and past its prime. This can happen within weeks or months in a closed bottle of wine, sooner if the bottle is open.

Even though a wine can start to taste acidic when it’s been sitting around exposed to oxygen, it’s not technically vinegar. Vinegar happens when the ethanol in a wine converts to acetic acid, and for that it needs the help of an acetobacter and lots of oxygen. In general, oxygen is not a wine’s friend.

—Dr. Vinny

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