Is there any health risk to humans from TCA?

Specifically, I understand TCA and its breathern to include:

a. 2,4,6-trichloroanisole (TCA),
b. 2,3,4,6-tetrachloroanisole (TeCA)
c. pentachloroanisole (PCA), and possibly
d. 2,4,6-tribromoanisole (TBA).

Do any of these compounds create a health problem for humans?

At least in the quantities that would normally be found in a glass or two of wine.

I'm not asking about any aesthetic issues here at all. Just whether ingesting any of these compounds could harm an otherwise generally healthy human.

This isn't a trick question: my researches so far have indicated that there is no health issue related to any of these compounds, only an aesthetic issue.

But, I would like to be sure I've covered this point.

Many thanks, Bob

Do any of these compounds create a health problem for humans?

Bob,

There is almost assuredly no known answer to your question. The only way that scientists could gain such evidence would be through very long clinical trials, with lots of people in them, to provide enough statistical power. The chemicals would be administered to the subjects. Blood and urine analyses would be regularly performed; records would be kept of all adverse events of these folks. In addition to reviewing lab results, physicians would adjudicate every serious event to advise on whether they thought it could be connected with the chemical.

Certainly no private companies would spend hundreds of millions of dollars to conduct such research, since none of them sell the stuff for therapy. Our government would only fund such studies if there was strong circumstantial evidence that these chemicals were significantly harmful, such as reports of liver failure from people who knew that they had consumed relatively large quantities. This would likely never happen.

Before this kind of real testing ever occurred, you would have many years of this expert or that opining that the chemicals may cause this or that, or that they are harmless, which doesn't mean a whole lot.

Covert

Covert has given you the proposal for a definitive solution--the double-blind controlled trial in a large population, which no one will ever conduct. What he neglected to mention was the large range of doses you would need to consider.

Short of a definitive answer, we can start guessing at probabilities. I'll start. There is no end to this sort of discussion if you really want to keep it going, but

Is the molecule known to be toxic in animals? Pure TCA is not acutely toxic until you pour the pure stuff in your eyes or down your throat. Related compounds are used in those foul-smelling antibacterial soaps at concentrations far higher than found in wine.

Does the chemical architecture of the molecule contain any obviously toxic bits (nitrones, epoxides, bay-shaped structures in polycyclic aromatic hydrocarbons, etc.), either acutely or chronically? Not to my eye. I mention that this isn't my core expertise, and that there are non-obvious toxins in the world. But most of the things that are non-obvious are bigger than TCA, allowing them to bind in a complicated way to an important bit of cellular machinery, or are more reactive.

But the item that I personally find most reassuring is the extremely low concentration of TCA in any wine you are likely to choke down. You can detect TCA at parts per trillion. Let’s assume you’re insensitive, and can only smell 100 parts per trillion. That means that TCA need only be 1 molecule among 10,000,000,000 others for you to notice it. Many things that you think of as quite toxic, Bob, are harmless when diluted out to that level. Cyanide, for instance, would do you no damage at that level of dilution. Only the most extravagantly deadly things produce noticeable effects when present in such miniscule amounts. The only reason you even know of the TCA is that it smells so very bad.

Another way of thinking about it is that there are other things in wine that probably do you more harm already, so you can neglect the tiny amounts of TCA. Other alcohols—methyl, propyl, butyl alcohols, the acetaldehyde formed in sherry or madeira from the oxidation of ethanol, and so on—these are found in far higher concentration, and are known to be toxic. You may occasionally have experienced that toxicity in the form of a hangover.

The most obvious chemical present in wine that can do harm is ethanol, which has complex and not always helpful psychosocial effects, can do down your liver, and probably helps at most doses to protect your cardiovascular system.

So, Bob, I’d mostly worry about acute and chronic ethanol toxicity when I think about wine.

Thanks Covert and Joe for two very interesting answers.

TCA's safety has been a moot point for me for several years-- at the first sniff (or taste) I've poured the bottle of wine down the drain. But Tim's recent apparently tongue in cheek comment about the "horrors" of drinking corked wine made me re-think the issue. In fact, I've never knowingly drunk corked wine, and I may be the poorer for not doing so.

Janet gave me a wine scent kit several years ago, and I supplemented it with a small kit of "wine flaws", including a small vial of TCA. That sample was so distinctive I can remember it vividly even now.

A couple of months later I attended an Executive Wine tasting of upscale Italian wines; according to my diary one wine stood out:


1990 Tignanello - Corked. 1*. Bob Millman said it was a 9.5 out of 10.0 corkiness on the corkiness scale. He suggested that we try to get something out of the wine anyway, but I find that the taste cork lingers on into the taste of other wines. Millman said that the tannins will survive corkiness, that the color was a very deep red, and that underneath the corkiness he could tell the wine had everything. [Tannic wet cardboard and dirty sweat socks? I'll pass!] Tuscany Italy.

I posted my notes, and Robert Callahan was blunt:


Millman should not after all these years be telling people to try to "get something" out of a corky wine. Commenting on what will survive in a corky bottle is absurd. It's a bad bottle - end of story.

I've taken Robert's advice -- like so much else I've learned on WLDG -- to heart for many years, and poured out many bottles of corked wine in the years since.

And yet, Tim's tiny "horrors" gnaws at me -- a bit sarcastic, perhaps, but certainly a wine lover that thinks drinking corked wine is not such a bad thing. Could Tim [and Millman] be right? Could I have been wrong all these years. Certainly I have no objective basis for thinking otherwise.

I'm pretty sure a good examples of corked wines will come up from my cellar over the next several weeks based on past experience, and I've decided to drink a few bottles to see if TCA is really horrible. Thus the reason for my question about TCA safety.

A few arguments in favor of the experiment.

1. Philosophically, it's always seemed important to try to understand other people's points of view -- TCA has advocates eager to extol its romantic and other aspects -- I'm ashamed to admit that I've simply rejected their arguments in the past.

2. Psychologically, I've always enjoyed trying new foods and drinks -- it's almost an addiction and it's been a great source of pleasure in my life.

3. As a corollary, I'm put off by "picky" eaters -- I cooked for several of my brothers and sisters and it was amazing at how many good foods they would refuse to eat -- or even try.

4. My initial reactions to new foods has sometimes been negative -- I hated beer for a week or two, and eventually guzzled many gallons of the stuff with real pleasure. Limburger, liver, chitterlings, a few other foods, took serious sampling before their pleasures shone through.

5. Trying new foods sometimes takes an effort of will -- for example, I shared a half dozen durians during a trip to Malaysia, with three different durian lovers -- before I finally understood the attraction of the fruit.

6. I've got a pretty short list of "disgusting" foods left to try -- Baalut is the leading contender at the moment. Baalut has proven surprisingly elusive to find; luckily, finding a corked wine will be relatively easy.

7. TCA itself has some interesting aspects; people use quite different words to describe the aroma and taste: "moldy" or "musty" or "earthy" or "medicinal" or "cardboard" or "wet cardboard" or "dirty socks". Tastes are difficult to describe in words, of course, but many wine descriptors are not particularly appetizing -- "cat pee" and "horse poop" spring to mind -- and the varying TCA descriptors suggest interesting possibilities.

8. Some TCA aromas and flavors seem to be created by "natural" compounds, one of the currently hot words in the food and drinks world.

9. Other TCA aromas and flavors are said to come from the winery structures and winemaking techniques; is corkiness is an essential element of a wine's "terroir"? Will the flavors and aromas, stay true to particular cork forests in Portugal? True to particular wooden beams in California or France? True to particular formulations of chlorine disinfectants?

10. And, perhaps most important, since TCA can apparently avoided, winemakers must actually intend to produce corked wines. The least I can do is try the results of their efforts and in Bob Millman's words "try to get something out of the wine". One has to respect the winemaker at least enough to actually try their products.

***

So, Covert, Joe and Tim, thanks very much for opening the door to yet another vinous adventure. I'll report back in due course -- the journey may not be as horrible as I've considered it to be these many years past.

Regards, Bob

Bob,
There is one.
If I breath on my wife after drinking a TCA infected wine, I will get a very nasty response. Understandable, I suppose; who wants to kiss a dirty gym sock (or is that Jim sock? - 'sorry).
Best, Jim

Same here, Jim. I'll have to remember that negative when I try my experiments. Thanks for the warning. Regards, Bob

Wow, Bob, what a ghastly idea.

Let me know how the bread is in your next slice of burned toast.

Milman is too cheap to have a backup ready, and is trying to persuade you that a bug is a feature.

Yeah, I mentioned that to Millman at the time after reading Robert's comment.

I was awfully new to wine at the time of that tasting. I still can't believe he made the argument, frankly. It was a really good tasting with 15 winners.

Thanks again for your wonderful answer to my question.

Regards, Bob

Another way to look at it.
Wine imbibers are probably exposed to TCA more than other populations, yet wine drinkers tend to live longer.

Regular wine drinkers regularly drink TCA at some level, which depends on the person.

Numerous epidemiological studies have been made to look for correlations between wine drinking and health (or disease). So far as I know, the only positive correlations to disease/toxicity are explainable by alcohol alone. (Also, there is some allergic sensistivity to sulfites in some people.)

If there were some mysterious residual correlation between wine consumption and another non-alcohol related disease or toxicity, then perhaps TCA could be one of hundreds of such candidates for the explanation.

In other words, one does not have to design a new study to look for connection between TCA and health risks. The null result from numerous studies appears to rule it out in the concentrations that normally occur in affected bottles.

Curiously, why worry about TCA at such low levels when known toxins (like crop sprays) undoubtably get into wine at comparable levels?

If I understand you Bob, you are purposely going to drink a TCA wine to see how bad it can be.

Wadda-u-nutz?

[James Roscoe]

I am nominating this thread for the "Wierdest Thread" of 2007! When will the prized Threadies be handed out?

10. And, perhaps most important, since TCA can apparently avoided, winemakers must actually intend to produce corked wines. The least I can do is try the results of their efforts and in Bob Millman's words "try to get something out of the wine". One has to respect the winemaker at least enough to actually try their products.

So, Covert, Joe and Tim, thanks very much for opening the door to yet another vinous adventure. I'll report back in due course -- the journey may not be as horrible as I've considered it to be these many years past.

Regards, Bob

Maybe I am tired. You are doing a great job of keeping me guessing whether you are kidding or not. Especially the last point about winemakers intending to produce corked wine.

But I don't mind TCA that much, and I have drunk entire bottles of corked Bordeaux. Somethimes I even like the taste a little. Actually liked a bottle of corked '97 Poujeaux a lot. I wouldn't like a steady diet of it, for sure; but I tend to like funky wine: rubber, asphalt and all that kind of stuff; so TCA isn't a huge departure for me.

Covert

10. And, perhaps most important, since TCA can apparently avoided, winemakers must actually intend to produce corked wines. The least I can do is try the results of their efforts and in Bob Millman's words "try to get something out of the wine". One has to respect the winemaker at least enough to actually try their products.

So, Covert, Joe and Tim, thanks very much for opening the door to yet another vinous adventure. I'll report back in due course -- the journey may not be as horrible as I've considered it to be these many years past.

Regards, Bob

Maybe I am tired. You are doing a great job of keeping me guessing whether you are kidding or not. Especially the last point about winemakers intending to produce corked wine.

But I don't mind TCA that much, and I have drunk entire bottles of corked Bordeaux. Somethimes I even like the taste a little. Actually liked a bottle of corked '97 Poujeaux a lot. I wouldn't like a steady diet of it, for sure; but I tend to like funky wine: rubber, asphalt and all that kind of stuff; so TCA isn't a huge departure for me.

Covert

OK Bob, you aren't nutz...Covert is.

Status Report.

Thank you all for your comments on this off-beat thread. It appears my protocol for tasting corked wines has found domestic disfavor and any results will be significantly delayed.

My plan had been to continue to drink wine from my own cellar from time to time, and when a corked wine appeared, as it does every ten bottles or so, I would "try to find what I could in the wine."

I would not have done so if guests were present or if we were planning a particular wine and food matching or if Janet had chosen the wine -- then the corked wine would have gone down the drain, following a number of its predecessors. For so long as the experiment continued, I planned to write up tasting notes in the normal course -- a full reaction as well as possible -- scrapping my simple "Corked" report.

Janet's reaction to the corked wine protocol was immediate and definitive: "Not in my house you're not!" [With Janet it's "our" house when there are floors to be laid, but "my" house when an interesting experiment is in the works.] There were words like "you'll smell", "the glasses will smell", "forget it", and so on.

My practical problem is that a corker has to come up from the wine cellar and Janet can't be home at the time. Since I rarely drink alone, results will not come pouring in as quickly as I had originally hoped.

As Socrates is supposed to have said: "Get married. If you get a good wife, you'll be happy. If you get a bad wife, you'll become a philosopher." The romance of experimenting with TCA delivery devices has been well and truly defeated by a longer, much more enduring romance in our house.

A few specific responses to your comments are in order:

1. The corked experiment was a bit inchoate when I asked the original question about the safety of TCA. I have not knowingly drunk a corked wine for many years, and if I drank say 30 to 40 bottles a year, my ingestion of TCA would have dramatically increased.

2. I suppose I also hoped to learn that perhaps there was a TCA health risk -- it might encourage winemakers to produce less corked wine. (My guess is that most serious wine drinkers pour out corked wine, even slightly corked wine which has less flavor that it might otherwise have. Therefore, relatively little TCA is actually ingested.)

3. I'm not sure how serious I was, or even am now, about actually trying to get something out of a corked wine. Time will tell -- the spirit of inquiry is willing, but gee I dislike the aroma of TCA.

4. I'm also not sure about the validity of my list of reasons for conducting the experiment. Some reasons are absolutely valid -- I'm a obsessive experimenter and a practicing omnivore for example -- and others reasons seem to have some validity in my mind.

Is corkiness a part of "terroir", for example? Do some winemakers want to make corked wines? Do some people really like the taste of TCA?

Whatever the validity of any of the reasons, the list was an exercise in thinking about TCA in a totally different way, quite different from my unthinking, knee jerk reaction, to pour the stuff down the sink.

5. Covert, thanks very much for your comments about TCA. I like lots of funky wines -- not as a steady diet but from time to time -- just as I like some pretty funky tastes in food -- again from time to time. Next time I drink a corked wine, I'll report in detail.

Thanks again to everyone, and regards, Bob

Opening too many corked bottles of wine, especially in a row, can be bad for the wrist and your blood pressure.

As to drinking, no thanks.

Bob,

This thread has to be a perfect one for my blog, but I can't figure out how. Can you?

I'm not sure, Thomas. For starters, feel free to put up any of my stuff, with or without attribution.

I pretty much wrote this off the top of my head, enjoying looking at corked wine in an entirely new way.

Have fun with it! I sure did.

Regards, Bob

Experiment 1 -- The TCA stars were in alignment last night -- Janet couldn't have alcohol, we had dinner at the Napa Valley Grill unexpectedly, and one of the three wines in the California Pinot Noir tasting lineup was corked (a 7 on a ten point scale, confirmed by Janet and the sommelier).

I decided to see how drinking the corked wine with dinner would affect the meal. Three conclusions:

1. TCA is a dominant taste.

2. TCA is a persistent taste.

3. TCA is a chameleon taste over time.

I tested the corked wine against two sound pinot noirs; both tasted corked, lacked fruit, and the first seemed much more acidic than it did before I tried it against the corked wine. My impression is that the TCA persisted even though I took a bit of bread and water between tastes of the wine.

I also drank the wine with three dishes:

Crab cake with a slightly sour pickle and a fruit coulis -- melon, berries and mango.

Coq au vin with potatoes, carrots and leeks, the skin of the chicken somewhat charred.

Espresso crème caramel.

I sipped a tiny bit of wine between each sample of the various foods, and found virtually no taste of anything except TCA with three exceptions:

The sour pickle tasted virtually the same as I remembered it from two weeks ago.

The charred skin of the chicken tasted burnt.

The grilled leek tasted like grilled leek.

Everything else was muted in taste -- the foods could have been anything, and each bite had a noticeable TCA after taste.

That TCA taste persisted for two hours or more after the meal.

The taste also varied from time to time, and I was reminded about how different people describe the flavor of TCA in quite different ways.

One last note: the food was not at all satisfying -- I left over half of everything, and Clive was very happy with three quarters of the chicken.

Regards, Bob

[James Roscoe]

Bob, has this all been an elaborate April Fools joke? If so, you are one sick puppy! You obviously have way too much time on your hands and need a hobby.

Fool, maybe, James, but it all occurred in March!

Bob, I think you need to go back and digest my last point. The great majority of wine drinkers cannot discern TCA ot tell that it is a defect. They drink the wine anyway. Thus, the epidemiological null result applies.

So, bearing in mind you recent report Bob, my answer to the original question is: there are no known physical health risks, but watch out for your sanity!

As far as I know, the class of chemical compounds that TCA and its friends belong to (the anisoles) are very aromatic, but not toxic in naturally-occurring concentrations, nor are they cumulative toxins.

In wine, they're obnoxiously present in parts-per-trillion concentrations. Unless you're talking about something really awful like botulinum toxin or polonium, almost nothing is toxic in that tiny a concentration.

TCA is just an annoyance, not a health hazard.

-Paul W.