Chemistry of copper in white wine: a review |
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| Authors: | A.C. Clark E.N. Wilkes G.R. Scollary |
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| Affiliation: | 1. National Wine and Grape Industry Centre, Charles Sturt University, Wagga Wagga, NSW, Australia;2. The Australian Wine Research Institute, Glen Osmond, SA, Australia;3. School of Chemistry, The University of Melbourne, Melbourne, Vic., Australia |
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| Abstract: | Copper is one element in wine that has considerable notoriety. While current winemaking practice tends to minimise the amount of copper that results from vineyard and winery sources, the addition of copper(II), either as its sulfate or citrate, to remove sulfidic off‐odours may result in an elevated concentration in the finished (bottled) wine. Residual copper in white wine has been linked to oxidative and reductive spoilage processes, although the mechanisms are at times speculative. The presence of copper has been implicated in haze formation (copper casse) and linked to protein instability. More recent concerns include the coexistence of residual copper and hydrogen sulfide in wine stored under low oxygen conditions. The chemistry of copper is important in both white and red wine. While there are some overlapping issues, especially with respect to sulfidic off‐odours, both white and red wine display their own unique chemistry. Thus, this review describes the state of knowledge of copper in white wine, differentiating between evidence‐based claims and speculation. It also identifies areas of research that will provide a much clearer understanding of the role of copper in wine spoilage. |
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| Keywords: | copper copper casse copper sulfide white wine wine oxidation |
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