It is extraordinarily pungent!
As with all chemical aromas, you really have to experience TCA to learn its odor. Think about how you would describe the odor of, say, vinegar to someone with no experience. You really canāt. Wet cardboard is not a good stand in for TCA, though for some reason itās become common to think that.
You have certainly smelled TCA before. As others have mentioned, it occurs in some packaged vegetables, notably carrots. It is common enough outdoors, often in decorative bark under the right conditions. I have found it in cooler, wet environments, like outside hospital entrances where bleach is probably in use.
As someone mentioned, maybe the best way to find an example is at a larger wine shop, where they likely have a few badly corked bottles lying around. Once you smell a badly corked bottle, youāll know the smell forever.
Hmm, I will say youāre unlikely to get TCA in just damp, moldy conditions. TCA is not a mushroom-y smell. You need a moldy environment, but you also need a source of chlorine. Chlorine bleach seems to be the culprit in most cases, but there are probably other sources. Anyway, your average damp, moldy environment isnāt a TCA producer. Youāll just get musty, moldy, old closet aromas from that.
Jim,
Lots of good info here from the comments before mine. I second that taking a piece of cardboard, soaking it, putting it in a wet paper-bag, and then leaving it for a week is a good way to get the āsmellā down. Like others have noted, the wines often taste dull, vague, and uninteresting.
No. No. No.
Everyone needs to stop with the handwaving, cardboard, dull, mushroom, all the other descriptors.
Corked means one thing: contamination with TCA (2,4,6-Trichloroanisole). One specific chemical compound, which has a unique and distinctive odor. No amount of handwaving description can convey to someone else what TCA smells like. You have to experience and learn for yourself what that odor is. What does cinnamon smell like? What do oranges smell like? What does peppermint smell like? What do peanuts smell like? What does vinegar smell like? I could go on, but you get the message. Once you smell any of those things, you know. Until then, no amount of description will convey the smell of cinnamon, oranges, peppermint, peanuts, or vinegar. Same with TCA.
Find a bottle of obviously corked wine, chosen by someone with experience who knows the aroma, smell it for yourself, and then youāll know. Smell, there is no substitute.
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Iāve noticed the same too - soft, spongy corks are weirdly correlated with corked wines. Not 1:1, but disproportionately so. Thank you for making me feel less alone in this
A correlation makes sense. The mold (if itās there) grows in seams in the bark. Obviously, soft spongy material is going to be more vulnerable.
Interestingly, I have not noticed any association of cork-taint with soft/spongy corks, but I do feel like Iāve noticed a certain type of very, very hard, tight and dry corks (difficult to get the corkscrew to turn through) that seem to be correlated with corked wine. This is purely anecdotal and may be a simple case of āconfirmation biasā and selective memory retention. But there have been cases where, upon beginning to remove the cork, and prior to smelling the wine (or the cork), Iāve thought āoh oh, I wonder if this is going to be corkedāā¦and then it was. I feel like whenever I get this initial āconcernā, the wine turns out to be corked as often as 25% of the time (more than twice the frequency that I normally encounter cork taint)
Ultimately, however, it is the distinct (and horrible) moldy smell, and not any apparent/visible characteristic of the cork itself, that is the definitive indication of a corked wine (and I have experienced plenty of corked wines having all types of corks). As others have noted, however, the sensitivity to the smell of TCA/cork taint is highly individual, and there are many people who simply canāt smell it, even at moderately high levels. I assume that for everyone, there IS a level at which they would smell it, but I donāt know that for certain, as I have experienced wines that appeared extremely corked to me, where another person simply couldnāt smell it.
When a wine doesnāt have that smell (i.e. itās not detectable to the tasters), it may appear that the wine is just rather flavorless or āblankā and inexpressive. In that case, the wine may be corked (or may not) and as suggested above, tasting the same wine next to a fresh bottle can be revelatory and confirm TCA in the first bottle. Another potential way is to try the same wine a couple of hours later. Sometimes the cork smell increases rapidly with time, so a wine with TCA that isnāt initially apparent by smell will become so after openingā¦
You simply might not have the sensitivity toward it that others might. I had the misfortune of opening two bottles in a single during a wine tasting event and both were corked, one lightly but one more so. A friend at the gathering couldnāt even tell that there was anything wrong with them.
But, Markus, I have been told more than once that I am an HSP. 
I have a pair of shoes that smell like TCA. If you are ever in Philly, you can come and sniff them.
Okay that sounded a little weirdā¦
If it was any other corner of the internet RIP Sarahās inbox
The thread is full of good advice.
- smell an acknowledged corked bottle so youāll know
- the old wet cardboard/newspaper aroma is definitely a good description of it
- when you have a question, if possible, open another bottle of the same wine, which will show you pretty clearly the difference
- sometimes, TCA just mutes the aromas and flavors without giving off the telltale cardboard aroma
I would add one thing - sometimes, TCA doesnāt reveal itself upon first opening the wine (or at least reveal itself at a noticeable level to a given taster), and you start to notice it later. Iāve had bottles I opened for a tasting and checked they were sound, then recorked, and showed up at the tasting with the bottle being solidly corked. So youāre not completely out of the woods by checking a bottle up front.
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Thatās an intriguing proposal, Sarah. Might be a more appropriate offer for a PM, rather than a forum post. Maybe we should take the conversation offline.
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Just donāt let the shoe contaminate a good wine.
Exactly. If there is any doubt, just leave a glass or a decanter full of the wine in question, and in an hour or more the smell will intensify.
Some people donāt have the receptor to detect TCA. TCA is something in the wine that doesnāt chemically alter anything in it. What it does is interfere with your data processing. Itās a red flag, where your brain is telling you thereās something you should be concerned about. To people who donāt have that particular receptor, the wine is fine. Their brain isnāt muting anything and thereās no musty smell. Lucky them. Anecdotally, thatās about 5% of people. Maybe thatās your case, Jim. (Imagine some truly great wine at some social event, your WOTN, and no one else wants to touch the rest of the bottle. Not a bad thing.)
As far as calling a muted wine corked, when thereās no tell-tale smell, that goes in the wild speculation department. Itās one of the possibilities, not a certainty. Donāt be āthat guyā pretending you know what you donāt know.
If youāve ever cleaned extensively with bleach, you probably know the aroma. We used a cleaner with a heavy bleach portion in the bar I used to work at decades ago. When I was educated on TCA later on I immediately flashed back to the common aroma from behind parts of the bar.
Like Alan, I wouldnāt try to approximate the smell. You just need to experience it for yourself. The very best way, if possible, to experience it is to open an untainted bottle at the same time. I would also caution against calling it a āmoldyā aroma. That is closer to brett.
If you are suspicious, stop swirling the wine. Put the glass down and come back in a coupla-few minutes. When you swirl you are releasing all the aromas that will compete, for a time, with the TCA. It will be more difficult to detect. Let it rest and the TCA will be more apparent.
Iām surprised no-one has trained dogs to smell and detect TCA. They could likely pick it up from half a mile away.
While I am in no way as sensitive as a dog, I have on more than one occasion picked it up from several feet away when people have popped a bottle. Its unnerving. Plus, you hate being the first one to catch it every time.