I know the knee jerk response is: any TCA is too much TCA. And I don’t subscibe to the idea that a wine is just a little corked. If I can perceive cork taint, I don’t drink it. I’ve been under the impression that low level TCA, although perhaps not apparent by smell or taste, will strip a bottle of wine of its fruit. So I’m interested in the following:
Is there a level of TCA that can be present in a bottle of wine that will not effect it in a way that is at all perceivable to any taster?
Is there a numerical level of TCA that while imperceivable to most tasters will strip a bottle of wine of its fruit?
At what level of TCA in a bottle of wine will most people be able to perceive it by smell and taste? I understand that there will be those who may not be able to identify it but still realize that the bottle is tainted.
Thanks.
In theory, even if I can’t taste it, at low levels TCA binds with other chemicals that enhance flavor, so it is always bad. Or so they say,whoever they is.
“Canadian wine researcher Dr. Ronald S. Jackson estimates that 99% of the population can detect TCA when it reaches a concentration of 200-300 parts per million. Individual human thresholds for detection may be magnitudes lower, but are generally considered to be above 5 parts per billion.”
In the same thread, it is stated that Bo Barrett says he cannot detect TCA below a level of 4.5 ppt. I understand that there is a minority that may be able to perceive TCA at significantly low levels. But I’m interested in knowing at what levels does it always effect a wine and when the majority of people will be able to detect it.
A Cork Quality Council study found more than 50% recognition of TCA in wine at 8 ppt and 97% recognition of TCA in wine at 32 ppt.
Another study found that TCA inhibits ability to smell, suggesting that the wine isn’t stripped of fruit, instead the smell we’d ability to detect the aromas are blocked (I’m not a biologist or chemist, so if I’ve misunderstood the study, I would welcome a correction by someone less ignorant than I am). It also found detection limits for TCA in the ppt range.
Sensitivity isn’t static through ones life. It can change with age and with experience. So if you accept that it changes for individuals, I don’t know that any study that claims a threshold level can be considered accurate as that threshold level could change for the same group when tested at a later point in time.
Yes, any amount is too much. It’s always a flaw, even if one can’t detect it. I guess it’s yet another thing for people to think that if they personally can’t detect it, it must not be a problem, which obviously makes no sense. The fact is that even if you can’t detect TCA in a given wine, that wine would taste better to you without it.
Is there a level below which it has no perceptible effect for any taster? Sure. One molecule of TCA in a bottle of wine isn’t going to do anything. OTOH, it would be very difficult to estimate the level at which it starts to matter for someone.
(1) Individuals vary widely in their ability to detect TCA.
(2) Even where everyone perceives it, different people react differently. I pick it out at least as often as other people I taste with, but I don’t find it as repugnant as most people. In some (not very frequent) cases I find it a tolerable flaw while others don’t.
The first question is interesting:
“Is there a level of TCA that can be present in a bottle of wine that will not effect it in a way that is at all perceivable to any taster?”
I’d be interested to see research on that, but I wouldn’t be surprised if there weren’t any. You’d need to have a lot of sample tastings, with all wines measured for TCA, and then match that with people’s perceptions that the wine wasn’t what they expected (as opposed to just being boring). Hard to frame that objectively.
How would you know for sure if you never tasted the wine untainted? It may affect the fruit long before you can sense the aroma. So I would go with David’s “Any TCA is too much”
The Cork Quality Council has done numerous studies. People vary widely in their ability to detect it and individuals are not necessarily consistent. The studies usually involve spiking some wine with known levels of TCA and giving them to panelists to evaluate. That has several flaws, one of them being the length of time the wine is left alone after spiking, but I don’t think the general take-away is materially going to be affected.
Keeping the above in mind, roughly a third of people tested can detect a difference at 1 ppt; and approximately 50% at 2 ppt.
With gas chromatography they can detect it at least down to .67 ppt.
About eight years ago they did a survey in Napa that was fairly widely publicized at the time. In addition to the inconsistencies noted above, they also noted that what your outlook and expectations are may have an effect on your ability to detect it. They found that wine makers and people in the industry could detect it at 1-2 ppt whereas people in the cork industry had much higher thresholds.
Here’s a link to that survey. It’s written in layman’s terms - it’s not from a science journal.
So people can detect it at extremely low levels but abilities vary. I am usually pretty able to detect it but I have no idea what the level is. I had a bottle from Navarra on Monday that I wasn’t sure about initially but the more I sat with, the more certain I was. In my tasting group I used to sit next to someone who couldn’t detect it if his life depended on it, not even when you could tell from the other end of the room.
If you want to search the literature, there are many cases of people noting it at 1 ppt. And then, as others have noted, sometimes you get the effect rather than the substance itself. So any amount is too much as far as I’m concerned.
The problem with studies like this is they don’t address the fact that mild (read: otherwise indistinguishable) levels of TCA rob a wine of fruit and brightness.
Indeed, I have a very low incident of wines with overt TCA-derived notes (maybe I’m not good at detecting it). But often wines are just dead and flat, which we usually blame on low rate TCA.
A lot of people who start enjoying wine don’t know what TCA is, and thus have no idea when a bottle is tainted. I think it becomes easier to identify TCA taint with more experience.
Where it becomes more of a judgment call is when a bottle underperforms expectations based on prior tasting experience with that wine. The TCA levels may be so low that you can’t small or taste it
directly; you only become suspicious because the aromas and flavors appears to be substantially muted.
I have to wonder about this. We’ve had several batches of wine in the last few years where every bottle of wine was tainted at around 1.0ppt and most of our professional customers could detect it. For most people 8ppt would be a stinker, and I wouldn’t want to be in the same room as 32 ppt.