Cork taint is a serious problem for both wine and cork industries worldwide. It produces a mouldy, musty and/or earthy aroma that masks the natural bouquet of the wine and reduces its quality. Halophenols and haloanisoles, particularly chloroanisoles, are considered to be the chief causative agents of this problem.

Wine contamination with this taint has traditionally, and erroneously, been attributed to the cork. However, studies have shown that the origin of wine contamination by halophenols and haloanisoles is environmentally based, arising from oenological products that have been in contact with chlorine derivatives used as pesticides or cleaning products. These volatile compounds are easily transmitted through the air and can contaminate wood, cork and other materials.

The most commonly used halophenols are pentachlorophenol (PCP) and 2,4,6-trichlorophenol (TCP). Although their use as pesticides has been banned in the EU for several years, they can persist in ecosystems for a long time. Despite these compounds being a cause of concern to wineries, there are conflicting findings about the actual incidence of and economic losses arising from contamination of wine by halophenols and haloanisoles.

A study by Copete et al.¹ investigated the occurrence of halophenols and haloanisoles in 966 Spanish aged red wines using stir bar sorptive extraction followed by gas chromatography/mass spectrometry. The presence of these compounds was also examined in relation to wine production and other oenological parameters. The results showed that 16.1% of wines were contaminated with one or several compounds, with the most abundant taint-causing compounds being 2,3,4,6-tetrachloroanisole and 2,4,6-trichloroanisole. Contamination with halo compounds was higher in wines from south-west Spain, followed by those from northern Spain. However, the mean concentration was always higher than the respective olfactory threshold, but none of the halo compounds represented a health hazard to consumers.
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¹ Copete, ML; Zalacain, A; Lorenzo, C; Carot, JM; Esteve, MD; Climent, M; Salinas, MR (2009). Haloanisole and halophenol contamination in Spanish aged red wines. Food Additives and Contaminants 26 (1) 32-38.

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