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Contaminated Cork: How to Spot It & Where It Comes From

Have you ever opened a favorite vintage or tried a new bottle that was supposed to be fantastic, only to be disappointed when you put your nose to the glass or took that first sip? The wine may have been affected by a contaminated cork—or “corked.” This is also referred to as “cork taint.”

Why Does Cork Taint Happen?

Made from the outer layer of the cork oak tree, cork can be contaminated by fungi and various microorganisms. This contamination can lead to the creation of a chemical compound called 2,4,6-trichloroanisole (TCA). When a TCA-contaminated cork is used to stop a bottle, it will transfer into the wine and ruin it for the drinker.

TCA does not present health concerns, but even in small amounts, it can affect the aroma and flavor of a wine. TCA can also form on barrels, wood beams, cardboard cases, wooden pallets, and other areas in wineries. If not discovered and removed, it can spread and eventually taint all wines at the facility.

Recognizing the Aroma & Flavor of a Corked Wine

Natural cork is used to stop about 70% of the world’s wines. This percentage is higher in fine wines. But before you think that any wine with a natural cork stopper will be at risk of cork taint, you should know that it is a rare issue. Estimates range that contamination occurs in less than 5% of corks. If you know what to look for in cork contamination, you can spot it and get the affected bottle replaced.

You may notice cork taint in the aroma of a wine. Some have described it as:

  • A moldy or musty smell
  • An aroma of wet dog, damp cement, or moldy basement
  • A smell of wet newspaper or cardboard

The flavor of a corked wine will be affected as well, resulting in:

  • A lack of flavor and fullness, specifically no fruit characteristics
  • An astringent (acidic or bitter) taste

The aroma is more likely to be affected when higher levels of TCA are present, while a lack of flavor may occur from lower levels of TCA. A rich, fruity wine may taste bland and muted if low levels of TCA are present. You could be disappointed in a bottle of wine without being able to pinpoint the reason why.

Will I Notice Wine Affected by a Contaminated Cork?

Sensitivity to cork taint varies. Depending on their palate, some people may immediately notice low levels of TCA in wine while others may drink it without noticing a difference.

If you notice that your wine has a musty smell, tastes bitter, or is simply flat and dull, you may be dealing with a corked wine. This might happen at a restaurant or during a tasting. If it does, talk to your server or sommelier immediately and express your concerns. The sommelier should smell and taste the wine to confirm your suspicions. If the wine is contaminated, it should be replaced at no extra charge. If you purchased a corked bottle of wine from a retailer or winery, contact them directly for a replacement.

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