2,4,6-Trichloroanisole (TCA)
Definition - What does 2,4,6-Trichloroanisole (TCA) mean?
2,4,6-Trichloroanisole (TCA) is a chemical compound primarily responsible for cork taint. Naturally occurring in wood, wine, water, soil, vegetables, fruit and cork, TCA is produced when airborne fungi and bacteria combine with chlorinated phenolic compounds, creating an anisole derivative. Additional TCA is caused by the pesticides used on cork trees, the wood preservatives used on the cork itself or the wood barrels wine is aged in, and - a former cause - chlorine bleaching to sterilize the wood used in wine production (chlorine bleaching has been replaced by peroxide bleaching).
TCA is transferred to the wine from or through the cork (bottle-specific cork taint) or from the winery (systemic TCA). Cork taint caused by TCA is evident in a musty odor that suppresses the natural aromas and flavors of the wine.
WineFrog explains 2,4,6-Trichloroanisole (TCA)
TCA is one of six causes of cork taint. It presents in wine with a combination of the following odors:
- Damp basement/cellar
- Damp cloth
- Mold
- Moldy newspaper
- Must
- Wet cardboard
- Wet dirt
- Wet dog
- Wet wood
TCA also suppresses the naturally occurring aromas in wine. A wine that is usually fruity or floral with an abundance of secondary and tertiary notes will smell flat and dull when there are high levels of TCA. The industry accepted level of TCA present in white and sparkling wines is 2 parts per trillion (ppt) - the equivalent of two teaspoons in 2,000 olympic-sized swimming pools; and 5ppt for red wines. However, people with very sensitive palates can detect under 1 ppt of TCA.
There are two types of cork taint caused by TCA - bottle and systemic. Bottle cork taint is caused by TCA being introduced into the wine either from the cork or through the cork. The cork itself could cause TCA by naturally occurring fungi or bacteria combining with the phenols in the wine; or fungi/bacteria could be introduced into the wine through faults in the cork. Systemic cork taint is caused when a winery has an abundance of TCA present in the wine barrels, pallets, drains and more. Systemic cork taint effects the entire batch of wine, usually only causing a level of 1 - 2 ppt. An acceptable level that means no additional TCA can be introduced or the wine will be ruined.TCA can be cured by soaking polyethylene plastic (milk bottles, plastic food wrap) in the wine. TCA molecules are attracted to the polyethylene molecules, binding to them for easy removal. Home fixes for cork taint can be done by pouring the wine into a jug lined with plastic food wrap, leaving it for a few minutes and then serving.
