Influence of Submerged-Cap Vinification on Polyphenolic Composition and Volatile Compounds of Barbera Wines

Abstract

This study compared floating-cap and submerged-cap vinification techniques for making wine from the Barbera cultivar. The submerged-cap method led to less extraction of phenolics during fermentative maceration than the floating-cap method. After soft pressing (0.5 bars), both the press wine and the marcs had higher total anthocyanin concentrations with submerged cap than with floating cap (+68.6% and +79.8%, respectively). No differences were observed between two submerged-cap trials with different pumping-over cycles during fermentative maceration. Despite the lower extraction of anthocyanins and tannins, at racking off the submerged-cap wines had significantly higher concentrations of total anthocyanins and total flavonoids than the floating-cap wines. The higher losses of total anthocyanins in the floating-cap wines were likely partly due to the greater importance of the enzymatic oxidation reactions in the cap, but especially to the more important precipitations of potassium bitartrate, enhanced by the higher extraction of potassium from the skins during fermentative maceration. The submerged-cap wines were also richer in tannins. The differences between the trials became statistically significant only after the union of the free-run wine with the press wine. For total anthocyanins, tannins, and color, these differences remained significant during the first year of aging.