Technical Yearbook 2023

OCTOBER

Wine in a can – rapid determination of a wine’s suitability for canning By Carien Coetzee

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Introduction Screening and compatibility tests are important to confirm the suitability of a specific wine for packaging in aluminium cans. 1 Incompatibilities can lead to the formation of off-odours (hydrogen sulphide) due to the interaction between wine components and aluminium. Before a wine is canned for commercial sale, can providers usually conduct compatibility tests to evaluate pack performance and wine quality over time. This ensures that the final product meets the minimum quality requirements and that no negative interaction occurs between the packaging and its contents. Usually, compatibility tests are conducted by storing packs for four months at 37°C. The elevated storage temperature accelerates the ageing process and enhances wine-packaging interactions (if any). If the wine quality and package integrity are acceptable after the storage period, then packaging for commercial sale can commence. This

method of compatibility testing has its advantages; however, it is time-consuming and perhaps not practically possible to perform for every wine destined for canning. A research group from Cornell University investigated and published a feasible method to determine the compatibility between a wine and a lined aluminium can in a test that can deliver results in as little as two weeks. 2 In this rapid compatibility test, wine is exposed to lined aluminium coupons for 14 days at an elevated temperature to evaluate possible metal-solution interactions. The use of coupons for corrosion testing is common in industrial settings as they allow convenient and reproducible evaluations. The coupons used for the rapid compatibility test are lined with the same coating to be used in the end product. After 14 days at 50°C, the hydrogen sulphide concentration in the wine is measured to determine if the liner has been breached and, therefore, if the wine and the liner are compatible.

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TECHNICAL YEARBOOK 2023