Winetech Technical Yearbook 2022

JUNE

ACTIONS IN CORK FORESTS TO PREVENT TCA

CONSUMERS DO NOT ACCEPT OFF-FLAVOURS IN WINE! THE APPEARANCE OF A MOULDY CHARACTER IS ONE SUCH FAULT. IT CAN BE CAUSED BY DIFFERENT ADDITIVES OR CORK CLOSURES.

BY CHARL THERON

Marking of trees enables the traceability of TCA (Amorim).

SINCE THE 1970s , 2,4,6-Trichloroanisol (TCA) has been a headache for the providers of cork closures for wine bottles. Advanced research by the companies involved has however addressed the problem in a major way and it will consequently be appropriate to take note of their actions. The problem solving can mainly be divided in two, namely the actions in the cork forests and the processes and/or techniques that were applied or implemented in the cork factories. In the past cork closures were usually divided into two classes, namely the so called natural corks and technical corks. Seeing that all cork closures are however dependent on the unique characteristics of suberin in cork bark, natural cork closures can be divided

into three classes. Firstly punched corks, where the cork is punched directly from the cork bark; secondly, moulded corks, where cork granules are pressed and bound together; and thirdly, the 1+1 cork, where a thin layer of cork is sliced and punched to the ends of an agglomerated middle where it is glued together. TCA is a very prominent sensory compound. A drop of it in an Olympic-sized swimming pool will have a concentration of 3.75 parts per trillion, which will be observed by most people as an unpleasant taste and aroma. The cork industry consists of a few large companies, which are mainly in Portugal. The most cork forests are also in Portugal (736 000 ha or 34% of the

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WINETECH TECHNICAL YEARBOOK 2022