Is there any health risk to humans from TCA?

Status Report:

In thinking about this experiment, I've realized that the most important finding was that TCA had a significantly adverse effect on the taste of the food as well as on the aroma and taste of the wine. This finding was so striking that there is no need to repeat the experiment (and the taste of TCA was so unpleasant that I'm not tempted to repeat the experiment for hedonistic reasons).

I'm not sure exactly how TCA does this -- I tasted the TCA but I don't think it over-whelmed the tastes of the food in the way, say, too much salt might over-whelm the taste of food. Instead, the TCA seemed to significantly interfere with my ability to taste many of the flavors in the food.

Hypothesis: TCA may reduce my ability to smell and taste food and wine, even if I can't detect the smell or taste of TCA itself.

In other words, TCA may act in a negative way in the same way salt does in a positive way.

Janet can't have salt in her food, but for some dishes she finds a little bit essential -- in particular a favorite chicken stew. The trick is to add enough salt to brighten the tastes of the stew, without being able to actually taste any salt. Janet is a master at doing so -- I can taste the difference between her salted and unsalted versions of the chicken stew -- the salted version is much more delicious -- but I can't taste any salt in the salted version.

If the hypothesis is true, the TCA problem may be much more significant than I've thought in the past.

I might actually be drinking wine containing TCA without knowing it, and getting much less flavor from the food than I would without drinking the wine.

There's some anecdotal support for the hypothesis.

1. We've had a number of discussions over the years on WLDG about wines in which the fruit was more muted than one would expect or desire -- Robin and others have suggested that an non-detectable amount of TCA might have been the cause.

2. Janet and I took a friend to Daniel a couple of weeks ago. At the suggestion of the sommelier, we drank a 2003 Northern Rhone wine, which tasted smoky and lacked -- we thought -- the amount of fruit the sommelier tasted and described in the wine. We all agreed the wine wasn't corked, but we differed on the amount of fruit we were tasting. I've dined at Daniel and its two earlier iterations with great pleasure many times; for the first time, we were all disappointed in the food. I do know that none of us finished our wine. Could an non-detectable amount of TCA in that Northern Rhone have adversely affected our ability to taste the food? Or did Daniel just have an off night?

Darned if I know.

As a next step, when another opportunity arises, I plan to dilute the corked wine with water until I can't smell or taste the TCA, and then drink the diluted wine with a meal. If flavors are adversely affected, the experiment might suggest that the hypothesis has some validity.

Regards, Bob

PS: Just for the record,

The Napa Valley Grille described the tasting flight as follows:

Pinot Noir $13.75
Understated & Elegant
1. 2005 Calera, Pinot Noir, Central Coast
2. 2005 Macmurray, Pinot Noir, California
3. 2004 Jekel, Pinot Noir, Monterey County

Janet and I found the Calera corked; the bartender agreed with us. He told me he had poured three glasses of wine from the corked bottle for other customers -- two tasting glasses of two ounces each and one six ounce glass for drinking (in addition to the eight ounces I purchased). The other three customers didn't complain about the wine.

Did those three customers recognize the corker, and grin and bear it without complaint? Did they not recognize it as a corker, and drink it anyway? I'm sure it must have adversely affected the taste of their wine. Did it affect the flavor of their food in a negative way?

Darned if I know.

More anon. Regards, Bob

[James Roscoe]

Have you died yet Bob?

Hypothesis: TCA may reduce my ability to smell and taste food and wine, even if I can't detect the smell or taste of TCA itself.

In other words, TCA may act in a negative way in the same way salt does in a positive way.

It most indubitably does, Bob. This phenomenon is known (to some at least) as "fruit scalping," a term I learned from Michael Pronay. I have long realized that, whereas I as a TCA-sensitive normally detect it as a "presence," less sensitive people tasting the same wine detect TCA as an "absence": the wine tastes flat, possibly thin, and lacks appreciable fruit.

It wouldn't surprise me in the least if TCA could have the same effect on food, but I can't say that I've experienced it (largely because I rarely if ever drink a corked wine, as I find the smell so repugnant that I avoid at all costs).

Mark Lipton

From one glass of corked wine, James? Not very likely.

[James Roscoe]

From one glass of corked wine, James? Not very likely.

From the title of the thread and the various experiments you were doing, I was beginning to get worried. Are your taste receptors dead?

I am impressed at the manner in which you have gone about this. I belive there ought to be an award in it for you!

"I have long realized that, whereas I as a TCA-sensitive normally detect it as a "presence," less sensitive people tasting the same wine detect TCA as an "absence": the wine tastes flat, possibly thin, and lacks appreciable fruit."

Thanks for chiming in, Mark. Like you, I'm very sensitive to TCA and often dump at the first hint of the aroma -- my wife is almost as sensitive to TCA as I am.

But, as our experience at Daniel indicates, it's possible that at there's an "absence" for both of us if the amount of TCA is below our normal level of sensitivity. I wish there were a practical objective way to measure TCA -- it would be easier to figure out at what level TCA affects not only the quality of wine, but also the quality of food eaten with wine.

At the moment, Janet and I have agreed that if the food in a meal is important -- and usually the food in our meal is more important than wine -- we'll dump the wine if there is less fruit than we expect. We are both sure we would have enjoyed our meal at Daniel more if we hadn't eaten it with that particular wine.

Thanks for alerting me to the term "flavor scalping". After 12 years of studying wine fairly intensely, there always something new to learn. I see there is a vast literature in food science on flavor scalping caused by packaging, not only in wine but in many other areas as well.

So far I haven't found much in support or in opposition to my hypothesis that TCA affects the flavor of food when the wine is the TCA delivery device.

Thanks again, Bob

"Are your taste receptors dead?"

Great shape for good food and good wine, James.

I thought at the outset I would have to drink a fairly large quantity of wine with detectable TCA levels -- detectable at least to me -- but that one glass was more than enough to convince me there was no pleasure, intellectual or hedonistic, in drinking any more of the stuff.

Regards, Bob

Hi Bob,
Isn’t it true that the perception threshold for a given substance is not an inherent property of that substance? One would think, because everyone has their own personal perception threshold for a given chemical substance and besides even these numbers will vary with the medium in which it is present, or if served with other food products that may also be contaminated with other organohalogen taints. For example the dried fruit themselves may not be detected as having a problem or fault, but after baking with such fruit the fault may now be noticed or detected.
The wide range of human personal perception threshold for a chemical stimulus makes it extremely difficult to identify taints and their possible causes.
Yes I can detect and recognize the smell of TCA from a vial with a given concentration of TCA, but can I actually recognize and detect that same concentration in a medium of wine?

Salute

Very valid points, I think. You've touched on a couple of issues that I'm still struggling with. In particular, I'm wondering if sensitivity to TCA is relevant at all -- without a practical, objective method of identifying concentrations of the compound, all of the factors you mention come into play and cause confusion.

[I keep hoping someone somewhere has a little strip of paper that changes color at different levels of TCA concentration -- like litmus paper.]

From a consumer's perspective, the key question may be at what level TCA adversely affects one's ability to taste, not just wine but food as well. That level may be well below the level at which TCA can be perceived.

Thanks for chiming in. Regards, Bob