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Chlorine In My Wine


Angelo P. — Myrtle Beach, South Carolina asks,

The barrel we fermented our red wine in was previously cleaned with pool chlorine. We washed it out several times to no avail. The wine was contaminated with chlorine. The wine smells and tastes bad. We racked it once. Is there a remedy?

Oh dear. I fear that your wine has been contaminated not just with chlorine, but with the dreaded TCA, or tri-chloroanisole aroma defect. Also known as the “corked” aroma, TCA is the scourge of winemakers the world over. Commercial as well as home winemakers have to be wary of this common wine aroma defect. The TCA aroma is caused when a naturally-present mold spore (from corks, or just in the environment) come in contact with ambient chlorine molecules from, for example, use of chlorine-based products in the winery. If conditions are just right, the mold spores might metabolize (ingest) some of the chlorine-containing compounds and spit out trichloroanisole as part of their digestive process. The result is a swampy, cardboardy “wet basement” type aroma that’s perceptible in miniscule amounts. It’s so potent that most of us can smell TCA at even such low concentrations as parts per trillion. The reason we call this the “corked” aroma is because natural wine corks are the usual vehicle for these mold spores. Be aware, however, that these mold spores can be introduced in
Response by Alison Crowe.