How To Tell When Wine Is Corked

how to tell if wine is corked - moldy corks

If you haven’t run into cork taint before, chances are you’ve at least heard of this odorous wine malady. Cork taint refers to a range of moldy smells that, in the words of Jamie Goode, “affect an annoyingly high proportion of wines.”

Smell the wine and see if it smells moldy or tastes less fruity. The taste of cork taint will linger in your mouth after you swallow. Humans are highly sensitive to cork taint and it affects around .03% to 5% of wines. Cork taint can be more obvious in light, aromatic wines, and you can train yourself to detect cork taint. If you suspect cork taint, take the bottle back to the store and ask for a replacement.

What Causes Cork Taint?

Most frequently attributed to corks, the musty smell comes from a chemical compound, 2,4,6-Trichloroanisol (TCA for short). It shows up in cork when phenolic compounds interact with chlorine.

How does chlorine get into the natural environment?

Insecticides containing chlorine were widely used around cork forests from the 1950s to the 1980s. Even though these insecticides are no longer used, their residue remains in the soil underneath the trees.

Who knew?

how to tell that wine is corked - vegetables
Baby carrots are notorious for the same mold that gives corks cork taint. Attribute: durera_toujours

A misnomer is that cork taint is limited to corks. The offending compounds can be found in barrels, too. Even just one portion of one stave in one barrel can be enough to infect the wine. But wait, there’s more…

Entire wineries can become contaminated.

Sodium hypochlorite (bleach) reacts with lignin, a wood compound, to create 2,4,6-trichlorophenol (TCP). Mold, yeast and bacteria then convert this compound into TCA.

Wooden pallets, packaging materials, wooden rafters and beams and plywood can all harbor microbes that will produce the offensive TCA.

The first known winery contaminated with TCA – that led to wine being contaminated with TCA – was documented as recently as 2004.

A flame retardant and a fungicide had degraded into TCA and infected the wine.

Today, wineries have a strict no-chlorine protocol as a way to mitigate TCA.

Some even go so far as to only use plastic palates for their packaged goods.

What Does Corked Wine Smell Like?

Corked wine can smell like any of the following:

  • Grandma’s basement
  • A house that’s been shuttered
  • Old moldy boxes
  • Cost Plus World Market
  • Decaying forest leaves
  • Baby carrots

Humans are highly sensitive to the moldy compounds causing cork taint. Most people can pick up on TCA at a concentration of 5 ng/L (5 parts per trillion).

This is the equivalent to a few drops in an Olympic sized swimming pool.

From an evolutionary perspective, being able to detect TCA may have helped us to detect moldy foods that could otherwise harm us. Some people cannot smell cork taint. 

If you’re not sure what you’re trying to smell, start with some pre-cut baby carrots as a reference point.

TCA is a chronic problem in the carrot industry and many of my winemaker friends can no longer stomach these orange fingerlings because of their strong association with an unforgivable wine fault. 

Once you know what TCA smells like, you’ll begin to identify it in your everyday life.

I have a favorite hike that passes through a particular oak grove where TCA washes over you like a wave. It’s unmistakable.

How Common Is Cork Taint?

Official sources vary on the prevalence of cork taint. According to Jaime Goode (whom I trust), we’re looking at a percentage of somewhere between 2%-5% of all wines that use a cork closure.

This comes out to a little under one bottle for every 2 cases of wine. 

According to Peter Weber, the Cork Quality Council estimates that the incidence of contaminated corks to be around .03%.

In the past month, I’ve enjoyed tasting about 55 wines and three were tainted, giving me a personal incidence rate of around 5%.

Are Certain Wines More Susceptible to Cork Taint?

Both inexpensive and premium wines can be affected by cork taint, but you’re more likely to notice cork taint in light white wines or even delicate reds, like Pinot Noir.

The moldy notes will mute these wines’ natural fruitiness. 

Bold, oaked red wines, like Cabernet Sauvignon, can have higher thresholds for TCA thanks to their powerful aromatics. 

How to Tell If a Wine Is Corked?

When you first open a bottle of wine, take a deep sniff of the cork. See if you can smell any mustiness. Look for faint or strong moldy aromas. 

Go back to the baby carrot exercise if you’re not sure what you’re smelling.

What To Do With Cork-Tainted Wine?

  • If you’re at a restaurant and suspect cork-tainted wine, send it back. This can be a little intimidating, but the waitstaff should accept the returned bottle with grace. In turn, they’ll return the cost of the bottle to the broker or distributor.
  • If you’ve purchased a bottle to enjoy at home and feel that it’s faulty, put the cork back in and take it back to the shop or winery with your receipt. The shop will exchange the bottle or refund your money. 
  • If you purchased the bottle online, reach out to the customer sales number to arrange a refund or exchange.
  • Unfortunately, if you’ve tucked bottles away during your travels into your suitcase only to discover they’re tainted when you return home, you’re likely out of luck.

Can You Get Rid of Cork Taint?

Once a wine has cork taint, there’s no way to get rid of it. TCA is a stable aroma compound, meaning that it won’t disappear over time, and it can even become even more pronounced as the wine ages or the wine opens up. 

Some will swear by plastic cling wrap, or Saran Wrap, as a way to neutralize the moldy compounds. You put the cling wrap in the bottle (or glass) of wine and let it soak. 

From personal experience, I can report this does little to resurrect an affected wine.

I also had my daughter question my life choices while I was shoving cling wrap down the wine bottle.

Is it REALLY worth it? 

Can You Drink Wine with Cork Taint?

Yes! You can absolutely enjoy – no scratch that – you can drink wine affected by cork taint.

You may not ENJOY wine that’s corked, but it will do you no harm.

Best case scenario, you’re one of the lucky few who cannot smell TCA. Worst case scenario, the wine leaves an earthy moldy note on your palate and you find yourself reaching for the water pitcher.

It May Not Be Cork Taint…

‘Corked’ tends to be the blanket term used for a wine that has some faulty quality, whether it’s TCA or any number of other potential problems.

Even professionals can miss corked wines as simply being muted or nonaromatic. 

Final Thoughts – Chances of Cork Taint Is Going Down

The good news is that wine lovers aren’t the only ones sensitive to cork taint.

The wine industry is accutely aware of how important it is to control TCA.

If you buy one bottle of wine from a producer and discover it’s gone bad, you may assume that the producer makes terrible wine and never go back to try another bottle.

Not only that, you’re likely to share your frank opinion on the wine’s mediocrity with your friends.

TCA makes for a bad business model.

As research on TCA improves, the overall incidence of cork taint is on the decline, a trend we can expect to continue as quality control measures evolve. 

In the meantime, go buy some fingerling carrots and get sniffing!

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