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 the winery environment from cardboard boxes, wooden pallets, or even old newspapers sitting around the cellar. When these mold spores encounter a chlorine molecule, stinky TCA is a possible result.
This is one of the main reasons I never let any cleaning agent containing chlorine cross my threshold. It’s also why you should always filter the water you use for cleaning, rinsing, or making additions in winemaking. I would retire that chlorine-cleaned barrel post-haste — cut it in half and use it to make a couple of planters outside. Since it is contaminated with chlorine and most likely with TCA, it has no further use in winemaking.
What to do with your TCA-smelling wine? You could try a little “wino-hack” trick that seems a little weird but, if the chemistry is right, sometimes works. Try balling up a few fistfuls of plastic wrap like Saran Wrap, putting it into a pitcher (about a 2–4 quarts/L size would work) and then pouring the offending wine over it. Let the wine and plastic wrap soak for a few minutes, give a stir, then pour off a sample of the wine into a glass. If it smells better, it means that some (or hopefully most!) of the TCA has absorbed onto the polyethylene plastic. Treat the rest of your wine this way and hopefully the level of TCA in your wine will reduce to such an extent that it can be consumed.
A TCA aroma defect is best prevented rather than treated. Never let chlorine cleaning agents come into contact with anything in your winery, buy a charcoal filter to run in-line or at the end of any of your water hoses, and make sure your corks are fresh and from a reputable supplier. It takes a little vigilance to reduce the incidence of TCA contamination in your winery but in this case an ounce of prevention is worth a few parts per trillion of stinky TCA taint.
Amendment Found in the August-September 2017 Wine Wizard
Dear Wine Wiz Readers,
Last issue, as part of a larger question from a reader about TCA (trichloroanisole, the “corked” aroma defect) prevention and management, I told readers about a “hack” I’ve heard about over the years. One soaks the wine in question with a fist-sized ball of plastic wrap, which will bind to the TCA to lessen its impact in the wine. Critically missing, however, was the important detail that the plastic wrap in question needs to contain PVDC (polyvinylidene chloride). A helpful and very knowledgeable reader, Rex Johnston, emailed WineMaker to help us clarify and update this response.
Here’s an excerpt from my answer:
“What to do with your TCA-smelling wine? You could try a little “wino-hack” trick that seems a little weird but, if the chemistry is right, sometimes works. Try balling up a few fistfuls of plastic wrap like Saran Wrap, putting it into a pitcher (about a gallon or half-gallon size would work) and then pouring the offending wine over it. Let the wine and plastic wrap soak for a few minutes, give a stir, then pour off a sample of the wine into a glass. If it smells better, it means that some (or hopefully most!) of the TCA has absorbed onto the polyethylene plastic. Treat the rest of your wine this way and hopefully the level of TCA in your wine will reduce to such an extent that it can be consumed.
A TCA aroma defect is best prevented rather than treated. Never let any chlorine cleaning agents come into contact with anything in your winery, buy a charcoal filter from a hardware store to run in-line or at the end of any of your water hoses and make sure your corks are fresh and coming from a reputable supplier with high turnover. It takes a little vigilance to reduce the incidence of TCA contamination in your winery but in this case an ounce of prevention is worth a few parts per trillion of stinky TCA taint. “
Mr. Johnston wrote to say the following:
“Saran Wrap was invented by Dow Chemical where I once worked. The original Saran Wrap was polyvinylidene chloride (PVDC), which has since been sold to S. C. Johnson, who changed the formulation to a polyethylene product that is not polar. The original PVDC is very polar and acts like a magnet to TCA which is also polar thus binding it up. Handi-Wrap, the new formulation of Saran Wrap, and other polyethylene products are not polar and will not bind up the TCA. Strech-tite sold by Costco is PVDC and will remove the TCA.”
Bottom line? If you do want to try to treat your wine at home with this hack, which does seem to work, you need to make sure that the plastic wrap you are using contains PVDC. Costco, here we come!
Thanks for sharing your experience with us, Rex!
