Assessing the distribution of 2,4,6-Trichloroanisole (TCA) in batches of natural cork stoppers remains a critical challenge for the cork and wine industry. The conventional method for quantifying TCA, outlined in ISO 20752 [1], involves gas chromatographic analysis of a cork soak. As this approach is time-consuming, costly, and destructive, TCA distribution is often estimated using pooled cork samples – so-called cork group soaks. However, the reliability of this procedure is questionable.
This study addresses the issue by comparing TCA distribution results obtained from cork group soaks with those from individual cork analysis across seven batches. Due to the high number of measurements required (approximately 3,500 cork stoppers), a method emerging as the new gold standard for TCA analysis was employed: the Vocus Cork Analyzer (VCA). This system uses chemical ionization – time-of-flight mass spectrometry to assess TCA in individual corks in just two seconds [2,3]. The technique is non-destructive, allowing cork stoppers to be sold after analysis by the VCA.
This study demonstrated that analyzing TCA in individual cork stoppers provides a significantly more reliable assessment of TCA distribution in natural cork batches compared to group soak analysis by ISO 20752. The latter can often yield misleading indications of TCA presence in cork batches, potentially leading to inappropriate batch rejection or acceptance.
For instance, we showed that two batches with a similar percentage of corks containing releasable TCA concentrations above 1.5 ng/L could produce conflicting results when assessed by group soaks. In such cases, the ISO method may suggest the presence of cork groups above the threshold in one batch but not in the other, despite similar actual distributions.
We confirmed that the Vocus Cork Analyzer enables rapid, non-destructive TCA measurement – just two seconds per cork – thus allowing for accurate and efficient assessment of TCA distribution in entire batches within minutes.