oenological tannins or commercial tannins, are products made by extraction of tannin from oak, chestnut, or birch woods and other suitable plant sources, including grape seeds. These have long been used (and are approved additives in many winemaking regulations) to improve the ageing characteristics, texture, depth of colour, and colour stability of red wines and also to inhibit laccase activity from Botrytis cinerea on red grapes. Our understanding of the way in which oenological tannins achieve these often desirable outcomes is no less partial than our understanding of wine tannin chemistry in general, but many winemakers have discreetly built up considerable practical experience in using these materials.
