The chemistry of copper in wine is both complex and fascinating.Fascinating to me perhaps because of the many years that I have spent working with the measurement of copper and trying to relate this to its role as a mediator of chemical reactions.When I first started this research,the question was copper's role as a mediator of oxidation.Winemakers were adding,and many still do add,copper(II)sulfate to remove any hydrogen sulfide off-odour.Internal winery communication did lead to an intriguing mistake in one case.The winemaker asked the cellar hand to add 2 mg/L’copper',or’2 parts’in wine industry jargon,to the wine.As the mass ratio of copper to copper sulfate is 1:4,the winemaker meant’add 0.5 parts Cu as 2 parts CuS04'.Of course,the cellar hand assumed that’2 parts Cu was 8 parts CuS04’resulting in a considerable excess of residual copper.Fortunately,yeast cells are effective bioremediators of metals,including copper,so most of the excess copper could be removed in this way.
展开▼
