Cork taint
As Korkton, also cork taint, corked, short cork, or Stoppler in the Austrian and known as cones in the Swiss, in the language of wine a smell and taste error of wine is referred to the as externally registered wine errors mostly on the closure of the wine bottle, the cork back. He is perceived individually different and leads to odor and flavor notes that can change the aroma of the wine and affect its taste or destroy.
A frequent cause of Korktons is the occurrence of a phenol derivative of 2,4,6- Trichloranisols (TCA ). The perceived odor experience often does not lie solely on the triggered by smell Trichloranisol itself, but also in the faltering olfactory perception of other aromas. TCA can interfere with the formation of olfactory signals in the olfactory sense cells ( olfactory cells ) even at very low concentrations, creating a smell is also reduced other odors or temporarily suppressed. Then only a flattened and modified profile is more noticeable, which some odor notes are missing.
The presence of trichloroanisole was long to bleaching of the punched Rohkorken with hypochlorous compounds, for example potassium or Javel water recycled. Meanwhile, the corks are predominantly hypochloritfrei bleached with hydrogen peroxide, without the frequency of occurrence of Korktons would have substantially reduced.
The formation of 2,4,6- Trichloranisols can already take place on the tree and could be due to various causes. One possible cause are bushfires, which occur relatively frequently in the south of the Iberian Peninsula, where most cork oaks grow, and which may lead to the cork in the formation of 2,4,6 -trichlorophenol. 2,4,6- Trichlorophenol is toxic to many organisms at a correspondingly high concentration and can be transferred from microorganisms by methylation in the less toxic and more volatile 2,4,6- trichloroanisole.
However, it has been the conversion of chlorophenol -containing fungicides, in particular of the pentachloro phenol commonly used earlier in wood preservatives investigated by microorganisms in the biological degradation. The highly toxic 2,3,4,5,6- pentachlorophenol ( PCP) is converted via 2,4,6 -trichlorophenol (TCP ) as an intermediate likewise to 2,4,6- Trichloranisol (TCA ). A reaction to avoid TCA in food is the EU-wide ban on pesticides in cork oak forests. From 1989 (pentachlorophenol Prohibition Act ), among others, the marketing of products with a content of more than 5 mg / kg PCP was banned in Germany. Based on the thick mass of a standard 20 mm, 4 cm short and well weighed 6 g cork from cork this would correspond to only a load of more than 30,000 ng PCP. Loaded cork could thus bring a natural product into disrepute.
TCA is also formed in other ways and can be transported not only of cork. So TCA was detected in coffee, beer, mineral water and other beverages and foods. Even with TCA contaminated plastic closures, carpets, filtration media, and many other products have been already identified. Even ground water has been contaminated by TCA, which was apparently caused by pollution.
After closure of the wine bottle with a cork, which contains a significant amount of TCA, moves a part of the TCA in a relatively short time (a few hours to 14 days) in the wine. TCA has a very low odor threshold value of about 2 ng / m³ equal to 2 pg (= 2 • 10-12 g) per liter of air and is for experienced wine taster, but also for consumers already at a concentration of 1-3 ng / L (billionths grams per liter) noticeable in white wines and from 5 ng / l in red wines. Over coffee the other hand, amounts in excess of 10 ng / l are often hardly noticed.
Can A range of additional materials for an odor described as Korkton responsible ( eg, 1 - octen-3 -ol). The description of the off-flavors ranging from woodsy to musty. Bromophenols example, are organoleptically indistinguishable from TCA.