Effects of cluster thinning on wine quality of Syrah cultivar (Vitis vinifera L.)

Cluster thinning is a viticulture tool used to correct overcropping, to improve fruit composition, and to find a balance between shoot growth and berry development. The main purpose of this study was to evaluate the effects of cluster thinning on the wine quality of Syrah cultivar under Mediterranean climate. Particular attention has been given to the volatile aroma compounds which are determinant for the sensory quality of the wine. Manual cluster thinning in the early stage of veraison was applied and compared with a not thinned control. Cluster thinning influenced yield reduction, advanced grape maturity, improved the phenolic content of grapes and therefore of wine, and influenced the volatile profile of wine. The grapes of thinned plants tend to get rich in varietal and fermentation aromas. Despite the economic impact, cluster thinning is a viable option due to the improvement in wine quality, especially for increasing the amount of compounds responsible for the typical aroma and color, at least in the Mediterranean climate where the search was carried out.