Kaolin over sun-exposed fruit affects berry temperature, must composition and wine sensory attributes of Sauvignon blanc

Under humid climatic conditions, crop loss due to bunch rot can be as high as 100% in a given year and, in many cases, it becomes the main factor determining harvest. Although the effectiveness of fruit zone leaf removal depends on initial fruit microclimate, it is generally extremely effective at reducing bunch rots. The impact of leaf removal on Sauvignon blanc must composition and wine sensory attributes, is in general considered detrimental. High temperature achieved as a result of excessive bunch exposure may negatively affect primary and secondary grape metabolites responsible for its typical wine style. The main objective of this work was to determine, if kaolin application over clusters, reduce sunburn and other berry damage associated with excessive fruit exposure. Three treatments were evaluated: untreated control (C); fruit zone leaf removal (LR); and fruit zone leaf removal plus kaolin application (LR + K). Kaolin application significantly reduced berry temperature, sunburn and other berry damage associated with excessive fruit exposure. Wines from the LR + K treatment had the highest sensory scores of all three treatments and were related more to a high intensity of fruity and tropical notes rather than to the absence of green notes as a consequence of leaf remova.