What TCA actually is
TCA (2,4,6-trichloroanisole) is a chemical compound that forms when certain fungi present in cork come into contact with chlorine — the same chlorine sometimes used in bleaches or pesticides during cork processing. It has nothing to do with the quality of the wine itself: an excellent wine from the best winery in the world can be ruined by a single contaminated cork.
How to spot it: your nose notices first
TCA has a distinctive, unmistakable smell once you've learned to recognize it: wet cardboard, mustiness, a damp old newspaper. What makes it tricky is that the human perception threshold is extremely low — some people can detect it at parts-per-trillion concentrations, while others, due to real genetic variability, barely notice it even when it's present.
Not dangerous, but it ruins the wine
TCA poses no health risk — it isn't toxic at the concentrations found in wine. What it does is flatten the fruit: it mutes fresh aromas, dulls the wine, and in severe cases leaves it smelling straight-up moldy. The intensity varies widely, from barely perceptible to an obvious flaw even for an untrained taster.
How common it actually is
Industry estimates put the problem at somewhere between 1% and 3% of bottles sealed with natural cork — not a trivial share, and one of the reasons screw caps gained ground on whites and young, high-volume reds, where consistency matters more than tradition.
A common myth: finding small bits of cork floating in your glass has nothing to do with TCA — that's just a cork that crumbled while being pulled. TCA is a smell problem, not a texture problem.
How you train your nose to catch it
Like any sensory defect, reliably spotting TCA is a skill built through repeated exposure and deliberate comparison — not something you learn by reading alone. It's exactly the kind of training LagarLab Plus's Advanced Tasting Room offers, with real TCA detection built into the simulator's sensory training.
What if you trained your nose on real cases?
In LagarLab you practice spotting defects like TCA in a controlled environment, with real feedback on every tasting.
Vinify for free: Agrelo (red)No sign-up. Prefer a white? Try Chablis.
Frequently asked questions
What exactly is TCA?
It’s 2,4,6-trichloroanisole, a compound formed when fungi in cork come into contact with chlorine. It has nothing to do with the wine’s own quality — a single tainted cork can ruin a great wine.
What does a wine with TCA smell like?
Like wet cardboard, dampness, or old newspaper. The human detection threshold is extremely low and varies genetically from person to person — some people can't detect it at all.
Is TCA a health risk?
No. It's not a health risk, it just flattens the wine's fruit and aromas.
If there are little bits of cork floating in the glass, does that mean the wine is corked?
No, that's a myth. Cork bits are just a cork that broke apart when it was pulled; TCA is purely a smell problem and has nothing to do with floating cork pieces.
How common is this problem?
An estimated 1% to 3% of bottles sealed with natural cork are affected — one of the reasons screw caps have gained ground.
How does TCA contamination happen?
TCA forms when certain fungi come into contact with chlorophenols, compounds that can come from chlorine-based cleaning products or treated wood, and transform them. The most common source is natural cork, which is why it's called cork taint, but it can also affect barrels, wooden pallets or a whole cellar if the environment is contaminated. That's why wineries avoid chlorine in their cleaning routines, and why some choose screw caps.