2,4,6-Trichloroanisole
IUPAC name	2,4,6-Trichloroanisole
Identifiers
CAS number	[87-40-1]
RTECS number	MFCD00000588
SMILES	COc1c(Cl)cc(Cl)cc1Cl
Properties
Molecular formula	C7H5OCl3
Molar mass	211.47 g/mol
Density	? g/cm3
Melting point	60-62 °C IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... RTECS, also known as Registry of Toxic Effects of Chemical Substances, is a database of toxicity information compiled from the open scientific literature that is available for charge. ... The simplified molecular input line entry specification or SMILES is a specification for unambiguously describing the structure of chemical molecules using short ASCII strings. ... A chemical formula is an easy way of expressing information about the atoms that constitute a particular chemical compound. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... For other uses, see Density (disambiguation). ... The melting point of a solid is the temperature range at which it changes state from solid to liquid. ...
Boiling point	140 °C at 28 torr Italic text This article is about the boiling point of liquids. ...
Hazards
R-phrases	Template:R22-36
S-phrases	S26
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Cork taint is a broad term referring to a set of undesirable smells or tastes found in a bottle of wine, especially spoilage that can only be detected after bottling, aging and opening. Though modern studies have shown that other factors can also be responsible for taint – including wooden barrels, storage conditions and the transportation of corks and wine – the cork is normally considered to be responsible, and a wine found to be tainted on opening is said to be "corked". R-phrases are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous substances and preparations. ... S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. ... The plimsoll symbol as used in shipping In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals exactly). ... For other uses, see Wine (disambiguation). ... A stopper is a truncated conical piece of rubber or cork used to close off a glass tube, piece of laboratory glassware, a wine bottle or barrel and other containers with orifices. ...

The chief cause of cork taint is the presence of 2,4,6-trichloroanisole (TCA) in the wine. Corked wine containing TCA has a characteristic odor, variously described as resembling a moldy newspaper, wet dog, or damp basement. In almost all cases of corked wine the wine's native aromas are reduced significantly, and a very tainted wine is completely undrinkable (though harmless). While the human threshold for detecting TCA is measured in the single-digit parts per trillion, this can vary by several orders of magnitude depending on an individual's sensitivity. Detection is also complicated by the olfactory system's particularly quick habituation to TCA, making the smell less obvious on each subsequent sniff. The olfactory system is the sensory system used for olfaction. ... In psychology, habituation is an example of non-associative learning in which there is a progressive diminution of behavioral response probability with repetition of a stimulus. ...

The production of TCA in wine is complex, but most results when naturally-occurring airborne fungi are presented with chlorophenol compounds, which they then convert into chloroanisole. Chlorophenols taken up by cork trees are an industrial pollutant found in many pesticides and wood preservatives, which may mean that the incidence of cork taint has risen in modern times. Chlorphenols can also be a product of the chlorine bleaching process ironically used to sterilise corks, which has led to the increasing adoption of methods such as peroxide bleaching. Divisions Chytridiomycota Zygomycota Ascomycota Basidiomycota The Fungi (singular: fungus) are a large group of organisms ranked as a kingdom within the Domain Eukaryota. ... A pesticide is a substance or mixture of substances used for preventing, controlling, or lessening the damage caused by a pest. ... This article does not cite any references or sources. ... General Name, symbol, number chlorine, Cl, 17 Chemical series nonmetals Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... Sterilization (or sterilisation) refers to any process that effectively kills or eliminates transmissible agents (such as fungi, bacteria, viruses and prions) from a surface, equipment, foods, medications, or biological culture medium. ... A peroxide is a compound containing an oxygen-oxygen single bond. ...

TCA is responsible for the vast majority of cases of cork taint, but other less common and less known compounds that can cause different varieties include guaiacol, geosmin, 2-methylisoborneol (MIB), octen-3-ol and octen-3-one - each has its own aroma, all of them considered objectionable in wine. Chemical structure of guaiacol Guaiacol, or 2-methoxyphenol, is a natural organic compound with the molecular formula C7H8O2. ... Geosmin is the organic compound responsible for the earthy taste of beets. ... Octenol (1-Octen-3-ol) is a chemical used to attract biting insects such as mosquitos. ...

Estimated occurrence of cork taint and industry response

The incidence of bottles with cork taint is estimated to be between 1 and 15 percent. The former figure is from the cork-industry group APCOR, which cites a study showing a 0.7-1.2% taint rate. Anecdotal evidence from wine professionals suggests that the rate may be substantially higher. In a 2005 study of 2800 bottles tasted at the Wine Spectator blind-tasting facilities in Napa, California, 7% of the bottles were found to be tainted.^[1] Associação Portuguesa da Cortiça is the Portuguese Cork Association, a consortium of cork growers and manufacturers. ... Wine Spectator is a lifestyle magazine that focuses on wine that was founded as a newsprint tabloid by Bob Morrisey in 1976. ...

Improvements in cork and winemaking methodology continue to strive to lower the incidence, but the media attention given to cork taint has created a controversy in winemaking, with traditional cork growers on one side and the makers of newer synthetic closures and screw caps (such as Alcan's Stelvin cap) on the other. Screw caps and synthetic corks, however, can be prone to another aroma taint: sulphidisation, which arises from the reduced oxygen supply which concentrates sulphurous smells arising from universal preservatives.^[2] For the Wikipedia policy regarding controversial issues in articles, see Wikipedia:Guidelines for controversial articles. ... Alcan (ALaska CANada) is also one of the common names for the Alaska Highway that connects Dawson Creek, British Columbia, with Fairbanks, Alaska. ...

There are now filtration and purification systems available which attempt to remove the TCA from corked wine to make it drinkable again.

Systemic TCA

Systemic TCA tainting occurs when TCA has infiltrated a winery via means other than cork and can affect entire production of wine instead of just a few bottles. This occurs when wine barrels, drain pipes, wooden beams in the cellars, and rubber hoses are tainted by TCA. Sometimes entire cellars have to be rebuilt in order to extinguish all potential systemic TCA culprits. Rubber hoses or gaskets have a high affinity for TCA and therefore concentrate TCA from the atmosphere. Wine or water that subsequently passes through infected hoses can become tainted with TCA. Another possible means of TCA contamination is through the use of Bentonite, a clay preparation used in treating wine for heat stability. Bentonite has a high affinity for TCA and will absorb TCA and related chemicals in the atmosphere. If an open bag of Bentonite is stored in an environment with a high (1-2 ng/g or ppb) TCA concentration, this TCA will be absorbed in the Bentonite and transferred to the wine lot to which the Bentonite is added. Wine barrels, especially those made of oak, have long been used as containers in which wine is typically aged. ... Bentonite - USGS Bentonite is an absorbent aluminium phyllosilicate generally impure clay consisting mostly of montmorillonite. ...

It is notable that often this systemic TCA will impart a trace (1-2 ng/L or ppt) to the wine, which itself is not detected by most consumers. However, with this high baseline level of TCA in bottled wine, even a relatively clean cork can elevate the TCA level in the wine above threshold levels (4-6 ng/L or ppt), rendering the wine "corked."

The primary chemical precursor to TCA is TCP (2,4,6-Trichlorophenol), an anti-microbial agent used in processing wood. Molds (and some suspect bacteria such as Streptomyces^[3]) are able to de-toxify TCP by methylating the -OH to -OCH3, which is not toxic. Chlorinated phenols can form chemically when hypochlorous acid (HOCl-, one of the active forms of chlorine) or chlorine radicals come in contact with wood (untreated, such as barrels or pallets.) The use of chlorine or other halogen-based sanitizing agents is being phased out of the wine industry in favor of peroxide or peracetic acid preparations. It should be noted that Chlorine dioxide has not been shown to produce these spontaneous chlorophenols. Wine Spectator has reported that such California wineries as Pillar Rock Vineyard, Beaulieu Vineyard, E & J Gallo Winery and Chateau Montelena have had trouble with Systematic TCA.^[4] Streptomyces is a genus of Actinobacteria. ... General Name, symbol, number chlorine, Cl, 17 Chemical series nonmetals Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... Barrel can refer to: Barrels for storage. ... A wooden pallet For the fictional town in the Pokémon series of games, named after an artists palette, see Pallet Town. ... A peroxide is a compound containing an oxygen-oxygen single bond. ... Properties: CAS no 79-21-0 Synonyms peroxy acetic acid, acetylhydroperoxide, PAA Physical data Melting point: 0. ... Chlorine dioxide is a chemical compound with the formula ClO2. ... California wine has a long and continuing history, and in recent decades has become recognized producing some of the worlds finest wine, matching the produce of the classic winemaking regions of France and, in some wine competitions, such as the historic Paris Wine Tasting of 1976, surpassing it. ... Beaulieu Vineyard was established in 1900 in Napa Valley, Californiia. ... The E & J Gallo Winery is a U.S. winery founded in 1933 by Ernest Gallo (March 18, 1909 – March 6, 2007) and Julio Gallo (March 21, 1910 – May 2, 1993) as E. & J. Gallo Winery. ... Chateau Montelena is a Napa Valley winery most famous for winning the white wine section of the Judgement of Paris tasting competition. ...

There are few means of reducing the level of TCA in tainted wine that are approved by the TTB (formerly BATF.) Some vintners have used Half & Half to remove TCA from wine (the TCA in the wine is sequestered by the butterfat in Half & Half). Other means of removing TCA from tainted wine is to soak polyethylene (a plastic used for applications such as milk containers and plastic food wrap) in the infected wine. The non-polar TCA molecule has a high affinity for the polyethylene molecule, thereby removing the taint from the wine. The surface area of polyethylene needed to reduce the taint to sub-threshold levels is based on the TCA level in the affected wine, temperature, and% Alcohol of the wine. The French company Boffin markets a product called "Dream Taste" which uses a copolymer shaped like a cluster of grapes to remove the TCA taint from commercial wine. TTB stands for Techno Talking Babe. ... The Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE or ATFE) is a law enforcement agency within the United States Department of Justice. ... This article does not cite any references or sources. ...

See also

• Alternative wine closures
• Flavor scalping
• Wine fault

Vinova synthetic wine closure Another type of wine closure Alternative wine closures are substitutes used in the wine industry for sealing wine bottles in place of traditional cork closures. ... Flavor scalping is a term used in the packaging industry to describe the loss of quality of a packaged item due to either its volatile flavors being absorbed by the packaging or the item absorbing undesirable flavors from its packaging. ... A wine fault or defect is an unpleasant characteristic of a wine often resulting from poor wine making practices or storage conditions, and leading to wine spoilage. ...

References

• Buser HR, Zanier C, Tanner H (1982). "Identification of 2,4,6-Trichloroanisole as a Potent Compound Causing Cork Taint in Wine". Journal of Agricultural and Food Chemistry 30: 359-382. doi:10.1021/jf00110a037.  DOI
• Tindale CR, Whitefield FB, Levingston SD, Nguyen THL (1989). "Fungi Isolated from Packing Materials - Their Role in the Production of 2,4,6-Trichloroanisole". Journal of Science of Food and Agriculture 49: 437-447. doi:10.1002/jsfa.2740490406. 
• Pirbazari M, Borow HS, Craig S, Ravindran V, McGuire MJ (1992). "Physical-Chemical Characterization of 5 Earth-Musty-Smelling Compounds". Water Science and Technology 25: 81-88. 

A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

Footnotes

1. ^ Wine Spectator March 31st, 2006
2. ^ BBC News Magazine Website
3. ^ Bacterial Causes of Winery Chloroanisole Contamination Paula A. Mara and Linda F. Bisson, Papers and Posters Presented at the ASEV 56th Annual Meeting 22–24 June 2005, Seattle, Washington
4. ^ J. Laube Taint Misbehavin Wine Spectator pg 43 March 31st, 2007

External links

• Article on corked wine

• Article on common defects in wine