Bottle capsules as a barrier against airborne 2,4,6-trichloroanisole

The possibility of 2,4,6-trichloroanisole (TCA) migration through synthetic stoppers and into wine from highly contaminated air was shown by several authors. However, those experiments were usually conducted without bottle capsules, which are a common part of wine packaging. In the current study, we demonstrated that the presence of capsules (without open holes) above synthetic stoppers can reduce wine contamination by airborne d₅-TCA by about 10 times or more. Generally, metallic capsules revealed better barrier properties than polyvinyl chloride counterparts. Application of EVOH film on the external surface of the polyvinyl chloride capsules usually resulted in a lower level of wine contamination. Additionally it was demonstrated, that relatively short exposure (3 months) of the bottles to highly contaminated air could cause a considerable absorption of d₅-TCA by synthetic stoppers, which can subsequently lead to wine contamination after 12 months.