What Exactly is a Corked Wine: And What Does Corked Wine Taste Like?

Most wine drinkers are probably familiar with the term 'corked wine', but I hazard a guess that not as many wine drinkers really know what a corked wine tastes like, how a wine becomes corked in the first place, or how to detect a corked wine. Read on to find out more about corked wine — how it happens, and what it tastes like.

How a Wine Becomes Corked
A corked wine does not mean a wine that has tiny particles of cork floating around in the glass. Corked wine is a term for a wine that has become contaminated with cork taint. Cork taint is not simply the taste of a cork. Rather it is caused by the presence of a chemical compound called TCA (2,4,6 - trichloroanisole). TCA is formed when natural fungi (of which many reside in cork) come in contact with certain chlorides found in bleaches and other winery sanitation / sterilization products. If a winery uses infected corks, the wine becomes tainted. If let loose TCA can contaminate not just a single batch of corks (and wine) but can infect an entire cellar or winery. Once entrenched it is very difficult to eradicate. Since the discovery (only as recent as the early 1990's) of the cause of cork taint, most wineries have totally eliminated the use of chlorine based clearing products.

The Taste of Corked Wine
While unpleasant to taste, cork taint is not in any way harmful to humans. Corked wines smell and taste of damp, soggy, wet or rotten cardboard. Cork taint dulls the fruit in a wine, renders it lackluster and cuts the finish. The obviousness of the corked smell and taste depends both on the extent of the taint, as well as the wine drinker's sensitivity to it (aka your cork taste threshold). Sometimes it is barely noticeable and other times it knock your socks off the moment you open the bottle. For example, while I am the wine professional in our household it is my husband who can smell the corked wine almost before the cork has been pulled, no matter how slight the taint.

All through the 1990's and early 2000's it was believed that the incidence of cork taint was as high as 7-8% of all wines bottled under cork. The rise in popularity of screw-caps and other alternate closures was in no small way attributable to the incidence of corked wines.

The Cork Industry's Response to the Problem
It is unlikely that the problem potential can ever be totally eradicated, but after a period of sticking their heads in the sand and ignoring the problem, the key players in the cork industry did set about finding a solution and today several advanced QA/QC procedures and treatments are in place to render cork less susceptible to developing cork taint. But it can still happen. Remember, we are talking about natural fungi which are everywhere, and of course various chemical reactions.

Cork: Wrongly Blamed for Other Wine Faults
Unfortunately, because the term 'corked wine' is more familiar to wine drinkers than the names of other wine faults, wines are often declared corked, when in fact the culprit is something entirely different. (Look for more on other common wine faults in a February post.)

Can I Bring or Send Back a Corked Wine?
If you discover that a wine you just opened is corked you have the right to bring or send it back. Retailers generally do not question it when you return a corked bottle — although it is best if the bottle is not almost finished!

In a restaurant, the same logic applies, however sometimes it can be a little more difficult or sensitive. If you are not used to looking for faults in wine, you may feel intimidated and not detect the taint when the sommelier or waiter first asks you to taste the wine. It may take ten to fifteen minutes for you or somebody in your party to question the wine. If this happens, my advice is to call back the waiter and explain, asking him or her to taste the wine. If the wine is indeed corked it should be immediately obvious to the sommelier.

Cork Taint: Increasing or Declining?
While I have not carried out any comprehensive or scientific study, from my own experience I have to say, that the problem does not seem as extensive as it did 8 to 10 years ago, when almost one in five bottles I opened was tainted. I open quite a few wine bottles every week, and these days it is often several weeks before I find a tainted wine.

I would love to hear from readers on your questions and /or experiences with corked wines.

Until next week, stay away from corked wines!

Mary Gorman-McAdams, MW (Master of Wine), is a New York based wine educator, freelance writer and consultant.

Related: Is Cork the Best Wine Stopper?

(Image: Faith Durand)

Comments (10)

Every once in a blue moon we open up a bottle of red and it has the slightest bit of effervescence and just tastes 'off'. What is this and what causes it?

Is it really that subtle in most cases?

I've identified 1 corked bottle of wine and it was really obvious when we tasted it (and I know next to nothing about wine). We both took sips from our glasses and said, this tastes NOT RIGHT. So we walked back to the shop (luckily less then a block away) and asked them to check it. Sure enough, it was corked. They gave us a new bottle. They told us they'll take back wine regardless, but a lot of times people just don't like the taste of whatever they chose.

To Rosebud - poor QA/QC at bottling - if a yeasty beasty is lurking around and the wine is not totally dry it will start to re-ferment. Not what you want to encounter. Will go more into this + other faults soon in another post.

To mamasparks - most times it is very obvious but not always.

I know it sounds funny but I'd really like to taste some corked wine. Not wine that is bad or off but one that an expert would agree is corked. Why? I have never come across it and I want to know what to look for when I do. I don't know anyone, in fact, that has tried corked wine.

I would like to make a clarification. You should consider the type of cork that closes the bottle. There is a difference between natural cork, cork sheets made from selected cork.
or agglomerate cork binders crushed and compacted.
Agglomerated cork and in specific types of wine have higher risk of taste of "corked wine"

Sygyzy: Maybe you didn't recognize it? If you have been drinking wine with natural corks over a few years you must have come across it. On the other hand, if you are younger than 30, maybe not... And something else: Heavy smokers seem to have difficulties recognizing it because the smoking impairs their sense of smell, at least that's my experience.

one benefit to having worked in a restaurant where I was opening and smelling about ten+ bottles of wine on a given night is that I know a corked bottle when I come across it. But even when I started, I feel like you just know when something "isn't right".

Another common "Corked" misinterpretation is when, during the wine making process air is able to bypass the cork and disrupt the wine. This will typically give the wine a very obvious vinegar flavour. This only happens with real cork wines, not screwcaps or rubber caps and is often visible in the cork itself because the wine will bleed through to the top (easier to see in red wines than whites). I recently opened a bottle of wine of this nature and you could see where the air had come in through a red line in the cork from one end to the other. I was going to return it, but my brother, who was staying with us at the time, found nothing wrong with it and drank the whole bottle! I can't imagine it tasting very good, but it didn't make him sick.

I've have a handful of horrible 'off' wines in my time. This included two bottles from the same store of the same wine, one was fabulous and the other utterly undrinkable. Even stranger most wines in Australia use screw caps now instead of cork and this particular bottle was a screw cap.

Can wines get 'corked' even with a screw cap or is there another culprit behind spoiled screw cap wines?