Modification of Cv. Merlot Berry Composition and Wine Sensory Characteristics by Different Leaf Area to Fruit Ratios

Abstract

This study aimed to evaluate the effects of cluster thinning and severe shoot trimming on berry and wine composition and wine sensory characteristics of Merlot variety, in the context of climate change challenges related to grapevine ripening and the corresponding high alcohol content in wine. In two seasons, two different crop sizes were obtained via cluster thinning and combined in a two-factorial design with severe shoot trimming (SST) and its respective high canopy control (HC). In both seasons, cluster thinning (CT) resulted in higher Brix in grape juice and higher alcohol in wine than full crop size (FC), whereas SST obtained lower values than HC. Total anthocyanins and phenolics in wine were increased by CT, whereas SST had no any significant effect on wine’s phenolic content. Several sensory characteristics of wine were positively affected by CT in both seasons, including aroma intensity, wine body and overall wine quality, whereas SST wines were in one season characterized by increased perception of vegetal aroma, acidity and bitterness, and decreased perception of body, persistency and taste balance. Our results demonstrate that practices which affect the leaf area to fruit ratio have a major impact on wine sensorial characteristics, concluding that their choice should be based on the desired wine style.