Compositional and Sensory Differences in Syrah Wines Following Juice Run-off Prior to Fermentation

The effect of running off 10% and 20% of juice from two Syrah musts prior to fermentation on the resultant wine sensory properties and composition was investigated. The concentration of total anthocyanins, phenolics and glycosyl-glucose increased and that of glycerol decreased with juice run-off, though the strength of the effects was dependent on the source of the fruit from which the wines were made. Declines in concentrations of anthocyanins, phenolics and glycosyl-glucose from pressing to 6 months of age occurred. The rate of decline was dependent on the fruit source but was independent of the degree of run-off. Formal sensory evaluation showed that run-off enhanced perceived colour intensity, and generally resulted in increased aroma, flavour and astringency.