Does cluster thinning improve Pinot Noir quality or just thin your profit

Crop yield is widely recognised as an important factor in the production of quality wine grapes. The traditional belief that low-yielding vines are associated with higher quality wines is often used to place an upper limit on the yield in commercial vineyards. The practice of cluster thinning has been used in order to regulate yield, and to improve the chemical composition of the remaining berries through manipulation of the leaf to fruit ratio of the grapevine. The aim of this study was to evaluate the effect of cluster thinning on the fruit quality of three Pinot Noir (Vitis vinifera L.) clones grown in Southern Tasmania. Grapevines were submitted to three cluster thinning treatments carried out at different times during the season; flowering, pea-size and veraison, as well as a treatment where only the wing of the cluster was removed (this was imposed at veraison) and an untreated control. Despite thinning well below commercial yield, and regardless of the timing of treatment there was no significant difference in pH, TA, or soluble solids, except for clone D5V12, where the total soluble solids (Brix) was significantly lower in the control compared with the three cluster thinning treatments. In conclusion, in good growing seasons cluster thinning can represent a significant yield penalty with no compensation in fruit quality.