Varietal and geographic classification of French red wines in terms of major acids

Concentrations of acids other than malic and lactic appeared to be related more to area of production than to grape variety. These variables (2- hydroxyglutaric, butyric and isovaleric acid concentrations) were attributed to differences in the technological process used for vinification in the various areas. Shikimic and galacturonic acids were helpful for classifying and discriminating wine varieties. Principal component analysis characterised Cabernet Franc, Grenache and Carignan wines well by their acid content but failed to discriminate Merlot from Cabernet Sauvignon and Cinsault. Stepwise discriminant analysis allowed a clear separation of all wines according to the different varieties and regions, except Cubernet Franc and Cubernet Sauvignon niade in Bordeaux. The eight groups obtained were charucterised by a selection of only nine vuriubles including 2-hydroxyglyceric, shikimic, hexunoic and galacturonic acids, volatile acidity, and citric, decanoic, 2, 3-dihydroxy-2-methylbutyric acid. Two-way analyses of variance applied to the Merlot and Cabernet Sauvignon wines made in Bordeaux and Narbonne demonstruted uery few or no interactions between the two factors of variation for most acids. This analysis confirmed the importance of shikimic acid for classfying wines according to the variety of the grapes and of 2-hydroxygluturic und tarturic ucids for location.