I can say, from smelling the pure TCA that Tom has encapsulated at his house, that it smells exactly the way TCA smells in wine, except at a much more intense level. And that’s outside its several containers! Granted, there are a lot of wine bottles in the vicinity (always!), but they are sealed and do not smell like wine in other parts of the room.
Kind of like asparagus pee
Adam,
Interesting indeed. Of course, the only way to know for sure is to test the wine for the presence of TCA.
There are many other potential reasons why a wine may lack aromatics, including slight oxidation, potential bacterial issues masking aromatics, ‘bottle variation’ . . .
Somewhat like certain diseases in humans - the only way to verify is post mortem . . .
And the fact that some can pick it up and other can’t may be due to a number of things - mainly the fact that we all have different sensitivity levels to ALL aromas . . .
Cheers.
Of course TCA has an aroma. It smells like flawed wine.
Seems this is just click-bait, and a poor translation of a scientific article by a writer who did not understand what they were reading and forged ahead anyway.
The scientific article cited partway through is 2,4,6-Trichloroanisole is a potent suppressor of olfactory signal transduction - PMC and while it is also well above my scientific literacy, it still doesn’t seem to say that TCA has no smell, only that it works in a different way than most aromas. That in addition to the unpleasant aromas we perceive, it basically works to block and distort our entire sensory apparatus.
The full scientific article is an exploration of how cork taint can mute our ability to smell and taste wine even when we do not smell the characteristic musty/wet-cardboard aroma, not a statement that the aroma doesn’t exist.
That’s also my reading of the paper. Indeed, it states TCA has an odor but the biological mechanism through is which the odor is perceived may be different than for most substances.
-Al
True all around. But the catch here was that the wine was not sufficiently tainted that it had any musty or other “off” aromas or flavours. The tasting room staff hadn’t smelled TCA (or its effects) when they opened it or served it to the previous 10 or so people who sampled it. They all just thought it was an uninteresting and muted wine. It was only after asking the tasting room staffer why the bottle was so different from the one I’d had two nights prior that they took a minute to evaluate it and declared it corked. Only after that statement did I learn about the fruit-muting effects of TCA, since that was more or less the rest of my discussion with that person the rest of the visit.
But, just because they declared it corked doesn’t mean it was. Larry notes alternative possibilities.
Another way to look at it is young wines in barrels can go through muted phases and come out later. That, while other barrels of the same wine don’t go through that. Any winemaker experiences that. We also get that sort of bottle variation pouring young wines sometimes. If you set that bottle aside and check on it later, you may indeed get that signature smell, or it may just sit there muted, or it may come around and start showing properly.
At group tastings where there’s a dispute over whether a wine is corked and there’s at least one claim of that musty smell, if it is corked, the smell becomes more prominent with time. There’s a very similar smell in some very mature wines which tends to fade with time. With both cases you’ll likely witness a notable opinion shift.
I read the research paper more carefully, and there may be a conventional explanation.
The study included measurements of the effect of TCA on biological cells and also utilized a small panel of human subjects.
The authors did not measure a response when they exposed individual olfactory receptor cells to TCA, but measured a large suppression of certain ion channels that are part of the signaling mechanism for these cells. These measurements were the basis for the claim (in the media article) that TCA has no odor, but would strongly suppresses signals from the receptors when they react to other odors.
The panelists could detect a musty TCA odor in all substances studied including wine, beer, tea, nuts, even mineral water and tap water. They state that the panelists had roughly the same TCA concentration threshold for noticing a decrease in other odors or for detecting the musty TCA odor.
The authors didn’t have an explanation for how an extremely low concentration of TCA can cause perception of a musty odor even if it did not seem to trigger receptor cells, but they offered several potential causes including that the suppression of receptor output may be interpreted as an olfactory response.
As far as the possible conventional explanation, they note that their cellular experiments used receptor cells from newts and that they don’t know whether they tested all types of olfactory receptors in newts. Also, there are genetic differences in olfactory receptor cells in amphibians and mammals, so it’s possible humans have receptors that are highly sensitive to TCA even if newts do not.
-Al
They state that the panelists had roughly the same TCA concentration threshold for noticing a decrease in other odors or for detecting the musty TCA odor.
The authors didn’t have an explanation for how an extremely low concentration of TCA can cause perception of a musty odor even if it did not seem to trigger receptor cells, but they offered several potential causes including that the suppression of receptor output may be interpreted as an olfactory response.
That makes sense.
Our perceptions adapt with continuous input over time, so as you smell a wine some more obvious odors decrease, which allows us to pick up more subtle aromas. That serves an evolutionary survival role.
Perhaps, for whatever reason, there’s some sort of need to directly suppress the TCA smell (so that it would actually be a lot worse at full volume) or there is/was something else that needed to be suppressed that way and TCA just happens to trigger that defense without the defense actually working on the TCA itself. Either way, it sounds like the suppression response is proportional to how much TCA our receptors register.
Yes, adaptation is key. Over time one’s sensory receptors adapt to virtually any aroma. The only receptors that have little or no adaptation are the cold receptors. The stimulus will continue to trigger the receptor as long as the stimulus is in contact with the receptor.
Tom