Wine Consumer


Number of Corked Wines is Down, but TCA is Still a BIG Problem, Steve Heimoff

The number of corked wines is definitely lower than it used to be. I’d estimate about 1 in every 30 bottles is notably tainted by TCA. It used to be about 1 in every 12 (humans vary widely in their sensory threshold to TCA; I’m about average), so let’s give credit to the cork industry for improved performance.

When I say “1 in every 30 bottles” I mean that 30th wine reeks of mold to the point where I detect it immediately on pulling the cork, in an “Ugh!” reaction that is always unpleasant. However, a new study on the effects of 2,4,6-trichloroanisole (TCA) leads me to worry more about the impact of sub-threshold TCA, which is far more common than overtly corked bottles.

The study acknowledges that TCA has long “been thought [to introduce] off-flavor substances [and] unpleasant smells” in affected wines. That would be the Ugh! factor. But the scientists also found–and this is the key sentence–“that …TCA…inhibits ciliary transduction channels…even at extremely low…concentrations.”

Lots of verbiage here, so let’s break it down.”Ciliary” is the adjectival form of the noun “cilia,” which are short, hairlike outgrowths from cells.  “Transduction” is the transfer of energy from one system to another–in this case, the transfer of olfactory sensations (smells) from the wine to our nose and brain. This energy transference occurs through the cilia in our olfactory neurons; they are the receptors that are stimulated by external odors, which then are passed along to the brain via olfactory nerve channels.

The worrisome aspect of this statement lies in its implications: Even if a wine does not smell overtly moldy or corky, there may still be enough TCA in it (“extremely low concentrations”) for its vinous aromatics to be inhibited or tamped down. This means that the wine will lack a vibrant aroma. If you’re a wine taster, you know that the aroma is possibly more important in judging a wine than anything else. It is certainly the first important signal (other than the color) that the taster receives about the wine (discounting foolishness like the weight of the bottle and length of the cork), and thus is likely to shape the taster’s subsequent [oral/flavor/palate] impressions. A wine whose aroma does not attract the taster’s attention is unlikely to be one he will signal out for praise.

I wonder how many dull, inert wines I review are actually infected with extremely small quantities of TCA, sub-threshold but with a consequent inhibiting effect on the aroma. It’s impossible to know, of course, without sending everything to a laboratory for testing. So my advice to the cork industry is to intensify their efforts to make every cork in the world 100% TCA-free.