How to tell if wine is corked

How to tell if wine is corked

What’s corked wine and how can you tell if a wine is corked? Wines that are corked are essentially spoiled because of a bad cork. You open the bottle and instead of fruit, you get a musty basement, wet cardboard smell and the wine doesn’t taste the way you’d expect it to. The underlying problem is not with the wine itself, but rather the cork which contains a type of molecule called Trichloroanisole or TCA for short. It transfers from the cork to the wine in the bottle and makes it go bad.

If you’ve never had a particular wine before, how do you know the mustiness isn’t just how it’s supposed to taste? One of the easiest ways is to sniff the wet end of the cork. If it doesn’t smell like wine and has an unusual odor to it, the bottle may be corked. Pour the wine in a glass, swirl it a few times, and taste it. Now wait a few minutes. If it’s corked, the longer the wine sits and is exposed to oxygen, the more you will get the musty cardboard odor. It will even increase in intensity. Keep in mind the cork itself will look perfectly normal. You’ll be relying primarily on your sense of smell and taste to tell you something’s wrong.

Science and history of “cork taint”

Cork taint is a condition where the cork that is put into a wine bottle contains Trichloroanisole. Cork taint isn’t a problem that only affects lower priced wines, any bottles that have natural corks can be compromised. The off wine can’t harm you (i.e. you won’t get sick if you drink tainted wines) but they aren’t going to taste very good.

The science and history of corked wines is important for people to understand

In the late 1990s and early 2000s, some people say up to 10% of wines were corked. This was partly because of an explosion in wine production which put increased pressure on material suppliers. Corks are made from the bark of the cork tree which is a kind of oak known as Quercus Suber. The tree grows in Portugal, Spain and parts of North Africa.

During production, the bark is stripped off (not to worry, it grows back). The problem is when the lower parts of the tree bark are used. Because lower bark is closer to the ground, it’s more likely to have picked up a particular fungus responsible for the problematic molecule. A secondary issue is when corks are washed in chlorine before use. In the mid-1990s it was discovered that this can actually activate TCA.

Corks can affect the bottle of wine you’re drinking and cause cork taint

Here’s the good news. Since then, the percentage of wines that are corked has dropped significantly and is now under 1%. This is in part because so many winemakers switched to screw tops. Also, they’ve developed better methods for washing and testing to detect if TCA is present before the bottles are closed.

The wine might only be a little off

It can be a sad discovery when you find a bottle is corked, especially when it comes to wine you were really looking forward to drinking. In some cases the wine might only be slightly off, think notes of cardboard. It’s still drinkable, but it smells strange and won’t necessarily be as enjoyable. Other corked wines can be terrible. The older the bottle and the longer the wine was exposed to the fungus, the more undrinkable it will be.

If this happens at home, you could always use it for cooking wine. However, if the wine smells really bad, the best solution is to just throw it out. If you’re at a restaurant, you should tell your server – see below for some tips on how to do this. Keep in mind this can happen at the best restaurants to the best wines.

Can both red and white wine be corked?

Yes, both red and white wines can be corked, as can sparkling wines and Champagne which tend to pick up the cork taint even quicker than still wine.

Corked wine has a musty cardboard wet dog smell

How can you tell if a wine is corked?

  • Smell the wet end of the cork. If it smells like musty cardboard, wet sheep dog, or a damp basement, the wine might be corked (note this isn’t always the case).
  • Swirl the wine and bring it to your nose before you taste it. The exposure to air that swirling causes will bring out more of the unusual odor. You will also notice that the normal fruit aromatics are muted.
  • Wait a few minutes. You’ll find a progression in the first ten minutes after pouring the wine. The more the wine is exposed to air, the more the odor will intensify.
  • Eventually, you’ll learn to recognize corked wines more easily. The more affected bottles you find yourself opening, the more readily you’ll know what you’re tasting (but hopefully you won’t have to experience this too many times in your life!)

Some people haven’t heard of corked wine

The bigger problem is that some people are unaware that wines can be corked and may just think they aren’t a fan of the wine or it’s low quality wine. This is especially the case if they don’t drink wine often or are having a wine for the first time and have nothing to compare the taste to. It’s one of the reasons why it’s so important to learn how to identify cork taint.

When you’re out to eat

When you order wine at restaurants, it can require a lot of confidence in your ability to detect cork taint and let your waiter know. Some people may feel embarrassed or worried that they’ve made a mistake, but don’t let this stop you. You should absolutely tell your waiter you think the wine is corked. There’s no reason to feel bad, as it’s not because of a fault in how the wine was made, stored or opened. Moreover, do it sooner rather than later so you’ve resolved the issue before your food arrives.

Top Tip: You aren’t hurting restaurants if you report corked wine because wholesalers will take the wine back and reimburse them. The same is true if this happens with store-bought bottles. Avoid pouring the wine out, just re-cork it and return it to the store.

Telling the restaurant your bottle of wine is corked is important - here’s what to say to your server

5 Tips for telling the restaurant your wine is corked

  1. Tell your server the wine has gone bad and you’d like another glass from a new bottle. Not everyone has heard of a wine being corked. This includes wait staff as well as restaurant managers and means you may need to explain what corked wine is. If you’ve ordered a bottle and approved it because you weren’t sure it was corked when you first tasted it, that’s okay. It takes a few minutes to let the smell develop. Explain this too and then ask for a new bottle.
  2. If they don’t believe you, you might have to request a manager or bartender step in. Have them pour the wine into a different glass and taste it themselves. You should also ask them to sniff the cork. (Note this is an important practice for people who work in restaurants to learn about anyway!)
  3. If the restaurant says it’s just how the wine is meant to taste, suggest they open a second bottle. Corked wine is somewhat random so the chances that the second bottle is also affected are very low. Ask them how it smells. There will be a clear difference between the two wines. One will smell of fruit, and one won’t.
  4. Remind the restaurant their wholesaler will reimburse them. They shouldn’t dump the wine but rather save it, re-cork it then give it to their sales representative the next time he or she calls.
  5. Thank you waiter for looking into the issue. Don’t penalize them by not tipping or leaving a bad review. Remember, corked wine is nobody’s fault and if they replace it, it shouldn’t have a negative impact on your meal. What’s worse is not to say anything at all and then not enjoy your food because the wine was off. You might even find the wait staff thanks you for alerting them to a wine that shouldn’t be poured!

What to avoid doing

We recommend not telling your server “this wine doesn’t taste good.” This is something people sometimes say when they aren’t sure they like what they’ve ordered. Stick to the truth and tell them you think the wine is corked. Also, don’t drink it. When people drink a few glasses of the wine before reporting the issue, it makes it less likely the restaurant will take their claim seriously.

Some people are better at identifying TCA than others

If you are still not confident in your ability to sniff out corked wine, don’t worry! Some people have a better nose for it than others. Moreover, if you’re tasting a large number of wines, it can be especially tricky. In an industry setting, there are often resident experts who are the best at identifying compromised bottles.

Why else might the wine taste bad?

The wine has been open too long.

If you’ve ordered a glass of wine and it doesn’t taste good it might not be that it’s corked but rather that the bottle has been open for a few days and the wine has oxidized and is no longer good.

Different reasons why wine tastes or smells bad, including if it’s corked

The wine has gone past its best drinking date

For older wines, it can also be that you’ve waited too long to open the bottle. It’s not always easy to know when you should drink a wine that’s being aged. If you can’t smell the fruit flavors and instead get more sulfur on the nose, it’s possible you waited too long or something happened to the bottle during storage that made the wine go bad.

The food you’re having with the wine changes how it tastes

While it’s a rare occurrence, it could also be that you’ve ordered a food and wine that don’t really go well together. As you eat more of the food, it changes the way the wine tastes, and not in a good way. This can happen with particularly strong food, like moldy blue cheeses. If you suspect an unfortunate wine food pairing, order a different dish and then have some water and a piece of bread to cleanse your palette while you’re waiting for the kitchen to cook your food. Alternatively, you could choose a different drink!

The wine is too warm.

If it’s summer and you find you’re not getting enough fruit as you expected, it might be the wine is too warm to drink. However, note there’s really no comparison in terms of it tasting corked. Tasting too much alcohol and not enough fruit on a hot day means you need to chill the wine. If you’re getting a wet cardboard and musty smell, then it’s corked.

Cork vs screw top wine

Corks are used for a number of reasons. To begin with, they’re more traditional and they cost less. Secondly and more importantly, they help some red wines age more gracefully. That’s because the natural material is somewhat porous and allows small amounts of oxygen in.

Nonetheless, because of the prevalence of cork taint in the early 2000s, a lot of wineries switched over to using screw caps. If screw tops are done right (wineries had to learn to add a bit of oxygen under the cap before putting the top on), they’re an excellent option for everyday drinking whites and red wines that are best when you drink them young.

  • Basic wine knowledge
author

Meredith is a freelance writer who writes about wine and food pairings in her free time. She spent many years working in the restaurant industry and even sold Côtes du Rhônes in the South of France a very long time ago.

Brian Keeping
Reviewer

Brian Keeping

Brian is an avid wine enthusiast and wine educator who has spent 45+ years in the fine wine industry. From 1975 to 1994 he was part owner and sales director of Silenus Wines and from 1994 to 2021 served as Fine Wine Director at Carolina Wines & Spirits.

Write a Comment

  • DEREK
    DEREK

    nice report, and yes, “stevin” screw tops have saved my wine enjoyment. I notice that the quality also tends to improve some hours or even a day after opening. The wine seems to be tightly held in a grip from its natural carbon dioxide from fermentation. I have even opened older bottles 10+ years that are wonderfully fresh. The one disadvantage seems to be that wines with stelvin are slow-starters, but “slow-food” also not negative….

    • Meredith Cicerchia
      Meredith Cicerchia

      You’re right, there’s a place for screw tops for sure. And how interesting about the older bottles. It’s especially wonderful to see a wine open up and still be so fresh.

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