The effects of two cluster thinning regimes (low and moderate) with Vitis vinifera cv. Pinot noir, in vineyards located in Central Otago, New Zealand, on wine composition, were studied across three consecutive seasons. There were strong correlations between the extent of cluster thinning and pH and bunch weights, and the concentrations of the C13-norisoprenoids, monoterpenes, fatty acids, cinnamic esters, β-phenylethyl alcohol, and all polyphenols. The sensory terms herbaceous and acidic consistently received the highest ranking in the control wines without cluster thinning. The thinning treatments produced wines with higher marks in the descriptors fruity, spice, sweet, and body. Cluster thinning also had a measurable effect on timing of harvest, in addition to effects on chemical composition and wine sensory, which demonstrate benefits to wine quality that can be expected with cluster thinning of Pinot noir.
Keywords: Pinot noir; cluster thinning; crop load; polyphenols; sensory; wine aroma; wine quality.