Chemical behind corked wine quashes other aromas

Old sock smell signals contamination but doesn't belong to TCA, study proposes

The musty stench emanating from a corked bottle of wine comes from a molecule that paradoxically dampens odors. Instead of smelling gross itself, this dreaded chemical, called TCA, unleashes its devastation by suppressing other smells, scientists propose September 16 in the Proceedings of the National Academy of Sciences

Outside of the wine cellar, suppressing scents can be intentional. Olfactory masks are commonly used to eliminate chemical odors in products such as shampoos, says study coauthor Hiroko Takeuchi of Osaka University in Japan. But winemakers go to great lengths to keep TCA, or 2,4,6-trichloroanisole, and the ensuing dank odor from spoiling their perfect vintage’s complex bouquet.

In experiments on newt cells, Takeuchi and colleagues found that tiny amounts of TCA potently hindered cells’ ability to detect odors. After a whiff of TCA, olfactory receptor cells produced weaker electrical signals, a sign that the cells were less active.

The results don’t explain the origin of the rotten sock odor that accompanies corked wine and other foods that go bad. (The researchers found TCA in a lot of other less-than-fresh products, including chicken, peanuts, Japanese sake, green tea and shrimp.) TCA’s odor-quashing ability might somehow evoke a moldy sensation in a way that’s different from normal odor detection, Takeuchi proposes.

Laura Sanders

Laura Sanders is the neuroscience writer. She holds a Ph.D. in molecular biology from the University of Southern California.

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