Terpene concentrations and wine quality of Vitis vinifera L. cv. Gewürztraminer as affected by grape maturity and cellar

The effect of grape maturity and juice treatments, namely skin-contact and heat treatment, on individual free terpene concentrations in Gewürztraminer juices and wines, as weil as on wine qualjty, was investigated. Total free volatile terpenes and total potentially volatile terpenes were also monitored during ripening of the grapes. Linalool, hotrienol, a -terpineol, citronellol, nerol, geraniol, diendiol-1, trans-geranic acid and the furan linalool oxides were analysed gas chromatographically. Wirre quality characteristics, such as fruitiness/ester-like, spiciness/terpene-like and overall wine quality of the wirres were evaluated sensorially. An increase in grape maturity caused marked increases in total bound terpene, as weil as in most individual terpene concentrations. Skin-contact for 4 and 15 h, respectively, and a combined treatment of 15 h skin-contact and heat treatment caused significant increases in the concentrations of the majority of terpenes analysed. Heat treatment resulted in decreases in geraniol, nerol and citronellol concentrations. The combined skin-contact and heat treatment resulted in higher intensities of fruitiness and spiciness, as weil as overall wine quality.