Influence of Potential Alcohol in Grapes on Phenolic and Sensory Characteristics of Red Wine.

Potential alcohol, as obtained by grape maturity, affects the extraction of phenolics during winemaking. The extent to which potential alcohol is correlated to phenolic and sensory characteristics of red wine was investigated. Decoupling of the ripening kinetics of grape constituents due to climate change emphasizes this question. The impact of potential alcohol, as naturally obtained by grape maturity or adjusted by sugar addition, representing high sugar but low phenolic maturity, on wine characteristics was investigated for two varieties over two vintages. Enhancement of potential alcohol to late harvest conditions did not achieve the sensory characteristics of wine made from phenolic mature grapes. An experimental model was developed revealing the contribution of potential alcohol to phenolic and sensory characteristics. In Pinot noir, anthocyanins correlated well with natural potential alcohol but were not influenced by enhanced potential alcohol. In Cabernet Sauvignon, polymeric pigments provided the most accurate information about grape maturity perception in wine.