Influence of the Presence of Grape Skins during White Wine Alcoholic Fermentation

The production of white wines with the presence of grape skins is a historical technique used in different regions with winemaking tradition. However, the current trend is to maintain the presence of grape skins during white wine making only during the pre-fermentation phase in order to enrich and give greater complexity to the sensory profile of the wines. Given these precedents, this study is the first to consider the effect of the presence of different grape skins doses throughout the alcoholic fermentation process. To this end, the effect of 5 different doses of grape skins (20, 40, 60, 80 and 100%) has been studied with respect to a control (0%) during alcoholic fermentation, the physicochemical composition of the final wines and a preliminary sensory analysis. The presence of grape skins has led to an increase in viable biomass and speed of fermentation with respect to the control. However, no differences have been observed in terms of the consumption of nitrogenous sources by yeasts. The wines produced have not shown great differences in their physicochemical composition, except for the volatile acidity. In addition, the preliminary sensory analysis showed differences between the different grape skins doses studied, where the wine produced with 20% grape skins has been the best evaluated by the tasting panel. In this sense, the production of wines with a 20% grape skins presence during the entire alcoholic fermentation is presented as a viable technique that would allow the diversification of the production of white wines and meet the trends and expectations of current wine consumers.