Corked wine is wine that has been contaminated by a chemical compound that gives it a musty, moldy smell and strips away its fruit flavors. About 3% of all bottles sealed with natural cork are affected, which translates to roughly 90 million bottles opened in the United States each year.
What Causes Cork Taint
The culprit is a molecule called TCA (2,4,6-trichloroanisole). It forms when naturally occurring fungi on cork bark encounter chlorine-based compounds, often residues from cleaning agents or pesticides. The fungi convert these chlorophenols through a chemical detoxification process, essentially neutralizing something toxic to them and producing TCA as a byproduct. Of 14 fungal strains isolated from cork samples in one study, 11 were capable of producing TCA when exposed to the right precursor chemical.
TCA is extraordinarily potent. Humans can detect it at concentrations as low as a few parts per trillion. To put that in perspective, one of the leading cork manufacturers describes its detection threshold as equivalent to a single drop of water in 800 Olympic swimming pools. You don’t need much of it to ruin a bottle.
How Corked Wine Smells and Tastes
The classic sign is a musty, moldy aroma, often compared to a damp basement, wet newspaper, or a soggy dishcloth left too long in the sink. Some people also describe an earthy quality. At low levels, TCA doesn’t always announce itself with an obvious stench. Instead, it quietly flattens the wine, muting the fruit and making it taste dull and lifeless. You might not smell anything overtly wrong, but the wine just seems oddly muted or “off.”
At higher concentrations, there’s no ambiguity. The musty smell dominates, and the wine tastes flat with a bitter, astringent finish. One wine critic described the full-blown version as “crushed-aspirin, wet-newspaper yucko.” If you’ve ever walked into a room with old, water-damaged cardboard boxes, you’re in the neighborhood.
Worth noting: a corked wine is not the same as a wine that has bits of cork floating in it from a crumbly stopper. That’s cosmetically annoying but harmless. Cork taint is a chemical contamination, invisible to the eye.
How Common Is It
Data from the Cork Quality Council puts the contamination rate at about 3% of natural corks. One longtime wine reviewer who tasted thousands of bottles over nearly a decade at Wine Enthusiast found that 3 to 6% of wines sealed with natural cork showed signs of taint, a figure consistent with the industry data. That rate doesn’t account for other related musty compounds like TBA (tribromoanisole), which would push the number slightly higher.
The 3% figure might sound small, but it adds up fast. Americans consume around 4.3 billion bottles of wine per year. If roughly 70% are sealed with natural cork, that’s over 90 million tainted bottles annually in the US alone. Many of those get poured down the drain without the drinker ever knowing the wine was corked. They just assume they bought a bad wine.
Can Screw Caps and Synthetic Corks Get Corked
Screw caps eliminate the cork-specific route of TCA contamination entirely, which is one of the main reasons more winemakers have adopted them. Synthetic corks also avoid the fungal issue present in natural bark. Neither closure will introduce TCA the way a natural cork can.
However, TCA can also originate in the winery itself. Contaminated barrels, hoses, tank coatings, filter pads, and even a winery’s atmosphere can introduce the compound into wine before it’s ever bottled. This is known as cellar taint or systemic taint, and it can affect wine regardless of closure type. It’s less common than cork-sourced contamination, but it happens.
What the Cork Industry Is Doing About It
Cork manufacturers have invested heavily in reducing TCA rates. The most advanced approach comes from Amorim Cork, which spent 12 million euros over six years developing a technology that individually screens every single cork stopper. Each cork is analyzed in seconds, and any stopper exceeding 0.5 nanograms per liter of releasable TCA is pulled from the supply chain. That threshold is well below what any human could detect.
These screening technologies have brought contamination rates down significantly compared to decades past, when some estimates put cork taint as high as 7 to 10%. The 3% figure reflects the current average across the industry, but corks that have undergone individual screening perform considerably better.
The Plastic Wrap Trick
You may have heard that wadding up a piece of plastic wrap and soaking it in corked wine can pull out the TCA. The theory has some scientific logic: the polyvinyl composition of plastic wrap attracts TCA molecules. Food science experts including the head of the enology department at UC Davis have endorsed the idea.
In practice, the results are disappointing. When Wine Spectator ran a blind test, pouring corked wine over crumpled plastic wrap and letting it soak for 15 minutes, two of the treated samples still clearly tasted corked. The treated wine that fared best showed slightly more fruit character than the untreated version, but the taster still wouldn’t drink either one. For the wine that wasn’t corked, the plastic wrap treatment actually dulled the flavors. The magazine’s verdict: the trick came up “bogus.”
What to Do With a Corked Bottle
If you open a bottle at a restaurant and suspect it’s corked, send it back. This is one of the main reasons servers pour a small taste before filling your glass. No reputable restaurant will argue with you about it.
If you bought the bottle from a wine shop, most will accept a return or exchange, especially if you bring the bottle back mostly full with the cork. Corked wine is a known manufacturing defect, not a matter of personal taste, and the shop can typically get credit from their distributor. If you purchased directly from a winery, contact them. Most will replace the bottle.
The one thing you can’t do is reliably fix it. Your best option when you’re stuck with a corked bottle and no way to return it is to pour it out and open something else.