Concord Wine Composition as Affected by Maturity and Processing Technique

Abstract

Concord grapes were harvested from the vineyards of the New York State Agricultural Experiment Station, Geneva, during the 1976 vintage. Wines were prepared by three techniques commonly used for producing Concord wines of various styles. A white wine was prepared from 12°Brix fruit that was pressed immediately after crushing, a red wine was prepared from 16°Brix fruit that was crushed and fermented on the skins, and another red wine was prepared from 16°Brix fruit processed by thermal vinification. All musts were ameliorated in order to produce finished wines containing 12% v/v ethanol. The flavor components of each wine were extracted with Freon 113 (1,1,2-trichloro-1,2,2-trifluoroethane). Compounds in the solvent extract were separated by gas chromatography and their odors evaluated using a sniffing device attached to the gas chromatographic effluent port. Nineteen compounds were identified by combined gas chromatography/mass spectrometry. The wines showed vastly different varietal characters that cannot be explained by variation in methyl anthranilate concentration alone. Sensory analyses were conducted in order to examine the correlation of odor intensity with methyl anthranilate concentration and total volatile concentration. This report demonstrates that the volatile composition of Concord wine differs significantly with maturity and processing technique.