[Differentiation of natural red wines from white wines blended with oenocyanine (author's transl)].

A method is proposed for the differentiation of natural red wines from those obtained by addition of oenocyanine to white wines. The procedure is based on the determination of tannin phenolics and nontannin phenolics by selective precipitation with methyl cellulose and subsequent estimation of the intensity of absorption at 450 nm and 520 nm. The sum of ratio: mg/1 non tannin phenolics/absorption at 450 nm X 1000 and mg/1 tannin phenolics/absorption at 520 nm X 1000, furnishes values which are in correlation with the origin of two wines and such as to consent their differentiation.