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Sep 18, 2013 07:45 AM

Japanese scientists claim cork taint in wine 'suppresses' sense of smell

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  1. That certainly fits my experience. I can't smell TCA in low concentrations that all my other wine-geek friends can. I only know a wine is corked because it smells muted compared with a good bottle.

    1. It kills wine. How it does so is totally irrelevant IMO. The wine is still dead.

      1 Reply
      1. re: jock

        Maybe it's of no interest to you but I find it fascinating that the perceived corked smell may be a sensory illusion, like an afterimage.

      2. Here's the actual study:

        "We investigated the sensitivity of single olfactory receptor cells to 2,4,6-trichloroanisole (TCA), a compound known for causing cork taint in wines. Such off-flavors have been thought to originate from unpleasant odor qualities evoked by contaminants. However, we here show that TCA attenuates olfactory transduction by suppressing cyclic nucleotide-gated channels, without evoking odorant responses. Surprisingly, suppression was observed even at extremely low (i.e., attomolar) TCA concentrations."

        Attomolar is parts per quadrillion? quintillion?

        1 Reply
        1. re: Robert Lauriston

          10 to the -18. (can't do superscripts right now) = parts per quintillion

        2. Hi, Jason:

          Yet another reason not to overtrain one's olfactory recognition of TCA.

          I fully expect someone here will claim that one part per quintillion is a "flaw" in wine that makes it undrinkable. Where are you Diogenes?


          1. Curious.

            The findings *suggest* the smell of cork taint -- that musty, moldy, old hymnal smell -- is the smell that's revealed when other smells are suppressed.

            Would love to see the experiment/findings corroborated in another study.

            10 Replies
            1. re: maria lorraine

              Seems like there's no actual mustiness to be revealed.

              "… the smallest effective concentration of odorants known to induce responses in individual ORCs is approximately 1 μM. On the contrary, the levels of TCA that would evoke musty odors (<5 pM concentration, or 10−4 fold lower) are extremely low for receptor-mediated biological mechanisms … We did not observe any detectable ORC excitatory responses in the experiments in which very low concentrations of TCA were applied to ORCs.

              "… we propose that the reduction of CNG channel activity may induce some kind of pseudoolfactory sensation by inducing an off-response, or the suppression of ORC output may itself induce an olfactory sensation."

                1. re: maria lorraine

                  In their observation the olfactory receptors are not being excited. I.e. TCA doesn't trigger the receptors for mustiness; apparently its suppression of the CNG channels somehow triggers that perception somewhere down the line.

                  It's something like an optical afterimage.

                2. re: Robert Lauriston

                  Hi, RL: "...pseudoolfactory sensation..."

                  We shoudn't be surprised, but perhaps we should be a little more humble...

                  What's the next realization? That there really is no such thing as dependable taste memory? I've made wine for years with a academic who claims to be able to perfectly remember every wine we've made. If he doesn't shut the F up soon, I swear I'm gonna burn him badly.

                  Taste the wine. Draw some general conclusions if you want--for yourself. If you like it, smile, drink more, maybe buy more. If you don't, push it away, but don't presume to know a lot more than that. Much more than that, and other things tend to get in the way. JMO.


                3. re: maria lorraine

                  Hi, ML:

                  "The findings *suggest* the smell of cork taint -- that musty, moldy, old hymnal smell -- is the smell that's revealed when other smells are suppressed."

                  I agree that's what the Decanter article (and the study author's quote) suggests. And that's an interesting theory. But there's no such suggestion in the study's abstract.

                  I find the more fascinating finding to be that truly infinitessimal levels of TCA far below even *your* trained threshold of perception can reduce flavor to an extent which IS perceptible, viz. "without evoking odorant responses."

                  Kinda freshens the perspective on the flavor "hallucinations" theory which was recently pooh-poohed here, too.


                  1. re: kaleokahu

                    It is unfortunate, as you point out, that Decanter did not report the study findings correctly.

                    Hasn't been peer-reviewed, so we'll see if what's suggested holds up.

                    1. re: maria lorraine

                      Hi, ML: "Hasn't been peer-reviewed..."

                      I'm unclear. This is a study published in the Proceedings of the National Academy of Sciences under the heading:

                      [A]ccepted by the Editorial Board August 15, 2013 (received for review January 13, 2013)."

                      Is this not peer review?


                      1. re: kaleokahu

                        You're right. I didn't catch that till I read the full text. Only saw that it was self-submitted.

                  2. re: maria lorraine

                    Yes . . . just as the absence of all color is black, apparently the absence of all odor is "musty."

                    1. re: zin1953

                      My understanding of the text is that the degree of odor suppression was the same as the human detection of cork taint. TCA exudes its characteristic odor, but also masks other odors. But again, the study needs to be peer-reviewed and corroborated. Pretty interesting. Would love to see studies on other olfactory mechanisms/cells.