Study Shows that New Methods for Producing Technical Corks have Virtually Eliminated the Problem of Cork Taint

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New production techniques allow cork producers to provide high performance, low cost wine closures that demonstrate taint-free behavior in a recently concluded bottling test.

Recent advances in the cleaning of cork granules have allowed Cork Quality Council members to achieve consistent high quality

In a three year study conducted by the Cork Quality Council, a range of technical corks were tracked through commercial bottling and aging for up to 24 months. Performance was evaluated based on the transmission of TCA to bottled wine. Comparisons were made between a variety of cork components based on grade and condition.

Bottled wines were tested at regular intervals by ETS Laboratories in St. Helena CA, using gas chromatography-mass spectrometry (GC/MS) techniques to analyze for TCA – the primary compound responsible for cork taint. The analytical method reported TCA in concentrations in excess of 1 part per trillion (1 ppt).

In the most popular form of technical cork, natural cork disks are applied to both ends of a cylinder comprised of specially prepared cork granules. The granules are large enough to retain the physical characteristics of a traditional natural cork, but are small enough so they can be economically sourced from the trimmings of production for traditional, natural wine corks.

Cork disks are applied to provide a 100% natural cork surface for contact with wine and to offer better extraction characteristics. Like traditional one-piece corks, these technical corks are made from the renewable bark of cork oak trees. They can be easily recycled after use.

In the Cork Quality Council study, wines were bottled with eight different versions of technical closures. Each represented different combinations of manufacturing techniques and component quality. In total, over 1,100 wines were bottled and analyzed for the presence of TCA.

Results demonstrated that the occurrence of TCA in bottled wine was closely related to the quality of the components used. There were 144 bottles finished with technical corks representative of current production methods and component quality. The results of their analysis produced not a single example of TCA above the reporting levels of 1 ppt.

Recent advances in the cleaning of cork granules have allowed Cork Quality Council members to achieve consistent high quality granulate that allows their technical corks to achieve excellent performance in bottling and aging of fine wines.

The Cork Quality Council has successfully developed and introduced methods for screening cork shipments for chemical associated with cork taint. These methods are now adopted as the wine industry standard. The CQC method is considered one of the primary reasons why the industry has seen such dramatic improvement in recent cork quality.

The Cork Quality Council is a non-profit group organized to improve quality assurance programs for its membership. The group is comprised of Amorim Cork America, Cork Supply USA, Ganau America, Juvenal Direct, Lafitte Cork & Capsule, M.A.Silva Corks USA, Portocork America and Scott Laboratories.

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Peter Weber
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