TCA (2,4,6-trichloroanisole) is the chemical compound responsible for what is commonly known as “cork taint,” where TCA suppresses a wine or spirit’s inherent aromas and adds its own musty, wet cardboard aroma, essentially ruining the drink, although it poses no health risk. Created when certain airborne fungi come into contact with the antimicrobial chlorinated phenolic compounds with which wood is commonly treated, TCA can ruin the character and aromas of a wine or spirit in even the tiniest amounts (five or six parts per trillion is a generally accepted threshold for detection by humans, although sensitivity varies widely between individuals). Although cork has been the main offender in conveying TCA into contact with spirits, other vectors can include barrels, labeling, and ambient distillery conditions.
Because spirits are increasingly being bottled with natural cork, the incidence of cork taint has been on the rise for spirits using such closures. Though data for spirits is scarce, in 2000, incidence of TCA was claimed to be as high as 10 percent of all cork-finish wines. The industry has taken action since, including more judicious care of the cork-oak bark processed into corks and the elimination of chlorine bleaching (chlorine is a catalyst for cork taint), and perhaps only 1 percent to 2 percent of cork-finish products may exhibit TCA today. But vigilance on the part of producers and consumers should continue.
Jackson, Ron. Wine Science. London: Academic Press, 2014.
Takeuchi, Hiroko, Hiroyuki Kato, and Takashi Kurahashi. “2,4,6-Trichloroanisole as a Potent Suppressor of Olfactory Signal Transduction.” Proceedings of the National Academy of Sciences 110 (October 2013): 16235–16240.
By: Doug Frost