Once you learn the musty, wet cardboard smell of 2,4,6-trichloroanisole (TCA) it's unmistakeable. TCA-infected wine is commonly referred to as "corky" or "corked". I've been smelling TCA a lot lately. No, we haven't been experiencing a raft of corky wines. In fact, the quality of corks has never, in my experience, been higher, or the incidence of corked Tablas Creek lower. I'm finding corkiness in unexpected places from housewares to the produce section.
A little science first. TCA, pictured right, is created when when naturally occurring airborne fungi come into contact with phenolic compounds in the presence of chlorine. (The closely related chemical 2,4,6-tribromoanisole is created through the same interaction of fungi and phenolic compounds in the presence of bromine.) Phenolic compounds are everywhere and include many of the flavors we taste and the aromas we smell -- including both the flavonoids and tannins in wine. In our modern world where water is routinely chlorinated and vegetables often washed with a chlorine rinse before packaging, so is chlorine. Chlorophenols are also produced during the chlorine bleaching process used to sterilize wood, paper, and foodstuffs. Bromine is nearly as prevalent in our environment, as tribromophenols are common industrial chemicals, added to wood to preserve it and used as fire-retardant agents in polyurethanes, plastics, paper, and textiles, and -- ironically -- as fungicides and antiseptics.
The fungi convert the phenolic compounds into chlorinated anisole (or brominated anisole) derivatives. Once they are created they spread rapidly as they are highly volatile. Plastic is not a barrier, and in fact can be a carrier. Shipping pallets have been identified as a primary vector of contagion. Heat and sunlight do both destroy these anisoles, and in fact putting infected materials outside on a dry, sunny day is one way to combat the problem. (Don't try this with wine.)
Corky non-wine items that have arrived at Tablas Creek have included the cork bottoms of marble coasters we bought to sell in our tasting room, the cardboard backing of a poster frame, and most ironically a shipment of wine bags: the six-bottle insulated nylon bags that wine reps use to carry their samples from appointment to appointment. In each case we've removed these from our premises as soon as they were identified. We've also eliminated all chlorine-based products in the cellar.
But it's not at the winery that I've been seeing corkiness, and I don't think that corkiness in wine is a growing problem. If anything, it's a declining problem in wine as wineries learn how to avoid creating it in the cellar, cork producers clean up their own harvesting and manufacturing processes (corks used to be harvested and left on the forest floor for months to dry, picking up plenty of mold spores, and then bleached with in a chlorine bath after cutting) and many wineries have simply switched to screwcaps, synthetic corks and other alternative closures.
No, the problem has cropped up in my lunch and in my home refrigerator. I honestly can't remember the last bagged produce that I opened that didn't smell at least slightly corked. Baby carrots are the ones that I come across most often, but I've found corky potatoes, green beans and apple slices in the last few months as well. And I have a real feeling it's just the tip of an iceberg. Jon Bonné of the San Francisco Chronicle wrote in April about a corked salad he received in a Healdsburg restaurant. George Heritier of the terrific blog Gang of Pour recently found a corked wine box. But if much (most?) packaged produce contains corkiness, given how volatile the responsible anisole compounds are, doesn't it seem likely that the warehouses where these foods are stored and shipped are infected? And how does that get cleaned up?
It's ironic that at the moment, the cork you pull out of the nice bottle of wine you're serving with your dinner may be the least likely culprit in your meal's musty, malodorous note.