Corks taints

Similar concerns involve the plasticizers in plastic wine corks, due to the presence of phthalates however, any such concern seems to have been negated by the use of screw caps or glass stoppers. In any event, with these new closures one can avoid the unpredictable moldy off-flavor cork taint characterized by a set of undesirable smells and tastes, called "corked" or "corky," that can arise in any wine with traditional corks, irrespective of price and quality level. 

Lee, T. H., Simpson, R. F. (1993). Microbiology and chemistry of cork taints in wine. In G. H. Fleet (Ed.), Wine Microbiology and Biotechnology. Chur, Switzerland Harwood Academic Publishers. 

Sefton, M. A, Simpson, R. F. (2005). Compounds causing cork taint and the factors affecting their transfer from natural cork closures to wine - a review. Austr. J. Grape Wine Res., 11, 226-240. 

Detection of Cork Taint in Wine Using Automated Solid-Phase MicroExtraction in Combination with GC/MS-SIM... 

Cork taint is a musty/moldy off-odor in wine. It is related to the cork stopper, a wine botde closure made from the bark of the cork oak (Quercus suher). In a correlation between sensory evaluation and chemical analysis, 2,4,6-trichloroanisole (TCA) has b n identified as a major impact component. In sensitivity tests of a group of trained wine judges, a geometric mean of the minimum detectable concentrations of TCA has been determined at 4.6 ng/L. 

Table I Cork taint and its economic impact on the US wine industry...

US cork stopper imports Average price Import value of corks Est. cork taint rate Est. value of tainted wine Est. costs for cork closures US wine exports (1996)... 

Although over 100 volatiles from finished corks have been reported (2-3), the one component that has been identified 4) as the major cause for cork taint is 2,4,6-trichloroanisole (TCA). In a recent study of Australian wines (5), 100% of the tainted wines, assessed by wine industry personnel, had TCA at or above the sensory threshold. The European QUERCUS study found TCA to be responsible for a musty/moldy taint in at least 80% of cases when it was detected in bottled wines. This makes TCA the most significant impact compound in regard to cork taint, and consequently made it the focus of our analytical developments. 

As mentioned earlier, even without being clearly identified as a musty/moldy off-character by the consumer, low levels of cork taint may be perceived as a generd loss of a wine s fruitiness, masking its aroma. 

Although some efforts have been made (25-26), until now there have been no statistically sufficient, rapid and cost effective sensory quality control (QC) procedures against cork taint for either wineries or cork suppliers. At UC Davis, we have developed a Cork Sensory QC Manual (27) which evaluates the major valid sampling procedures, and exemplifies their use based on a case study at a premium winery in California. In addition, the manual provides instructions for a taste panel evaluation which is essential for wineries in order test their winemakers and cellarmasters as well as the tasting room staffs sensitivities to detect the off-odor. Once individual... 

We have used headspace SPME in combination with GC/mass spectrometry-select ion monitoring to analyze for cork taint impact compounds in wine. Table II lists the analytical parameters that the authors developed for the analysis of TCA in wine (37). 

The causes for the majority of cases of cork taint have been quite thoroughly investigated mostly due to efforts from Australia (38-40) and to a certain degree tom Europe. Although the problem of cork taint poses enormous financial losses upon wineries worldwide, the funding of research efforts in different wine producing regions has been quite variable (Table III). 

Table III Estimated cork taint research funding 1992-1997...

Fuller, P. (1995) Cork taint. Closing in on an industry problem, The Australian and New Zealand Wine Industry Journal, 10(1), 58-60. 

Soleas, G.J., Yan, J., Seaver, T. and Goldberg, D.M. (2002) Method for the gas chromatographic assay with mass selective detection of trichloro compounds in corks and wines applied to elucidate the potential cause of cork taint,/. Agric. Food Chem., 50 (5), 1032-1039. 

Although TCA is considered to be the primary cause of cork taint, other compounds found in corks can contribute to wines taint, such... 

This compound is responsible for a fungal must taint reported in the wine cork industry. Characterized by unpleasant, musty, moldy odor, and a sensory threshold in white wine of 2.1 ng/L, this compound has been assessed as the second cause of cork taint (Simpson et al., 2004). Bacteria capable of producing 2-methoxy-3,5-dimethylpyrazine could be present in areas where the cork is processed or stored. 

Buser, H.-R., C. Zanier, and H. Tanner. 1982. Identification of 2,4,6-trichloroanisole as a potent compound causing cork taint in wine. J. Agric. Food Chem. 30 359-362. 

Some of the odor descriptions noted by the same authors are dusty, musty, earthy, wine cork taint, iodine, phenolic. 

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