Corked and corkiness are terms used to describe wine tainted by a sneaky compound called 2,4,6-trichloroanisole or, for the scientifically impaired, TCA. When TCA and wine cosy up, the result is an unfortunate mustiness, like dank towels that should have been washed weeks ago or a stack of mildewy newspapers in your hallway.
Conservative estimates suggest 5 per cent of the world's wines are corked - a defect level that would be unacceptable in most industries. After decades of ignoring complaints, the cork industry is scrambling to eradicate TCA, but despite sanitisation techniques ranging from chemical treatments to beta-irradiation, cork purveyors still cannot ensure these little pieces of tree bark are taint-free. Cork is, after all, a natural product.
Complete TCA eradication is impossible, argues the cork industry, because it is only through exposure to chlorine-based products, which producers no longer use, that harmless cork mould spores form the nasty TCA compound. Unfortunately, the chemical is pervasive and is used to bleach materials in shipping pallets, cardboard boxes and even wooden supports in winery walls.
Human sensitivity to corkiness varies, but most people are able to detect TCA in infinitesimal concentrations: as low as six parts per trillion (ppt), which is the equivalent to a 10th of a finger nail compared with China - or 40 hairs in Hong Kong. At lower levels (two or three ppt), TCA will not be detected by 99 per cent of the population because the musty character is greatly diminished; nevertheless, the wine is damaged. At these low levels, TCA gives the impression the wine is austere, as though the fruit has been 'flattened' or 'dumbed down', which particularly irks winemakers as it drives unwitting consumers away from their brand.
In response, winemakers are increasingly moving towards screw-cap closures or cork alternatives, such as plastic 'corks' or glass stoppers. Tradition dictates that the winery take responsibility for tainted wine, which results in a tedious paper chain leading from retailer
to distributor to importer to winery. Fed up with the imposition of corked wines, many large supermarket chains in Britain have demanded key suppliers package their wines with TCA-free screw-cap closures.