Physiological and Enological Implications of Postveraison Trimming in an Organically-Managed Sangiovese Vineyard

Abstract

For the first time, grapevines subjected to a single postveraison trimming were compared with never-trimmed controls, to assess its effects on vine physiology and grape and wine quality. In 2013 and 2014, postveraison late trimming (LT), performed at 15 Brix, was compared with an untrimmed control (CK) and early (pea-size) trimming (ET). Late trimming increased the berry skin total anthocyanin and phenolic concentrations without modifying the berry soluble solids, pH, and titratable acidity. It also reduced yield and malic acid levels at harvest, loosened bunches, and limited the severity of botrytis bunch rot. Improved berry color and decreased malic acid levels were observed in ET vines in 2013 only. Bunches from ET vines showed higher compactness and discoloration than those of LT vines. Trimming did not modify the main chemical characteristics of the wine, such as alcohol strength, dry matter, pH, and titratable and volatile acidity. However, in both years, a notable increase in color components and tannins was found in LT wines, with the formation of more stable components able to enhance wine quality, while ET had less impact on wine color characteristics. The enological benefits induced by late trimming were more apparent following wine storage. Late trimming was an effective practice to improve the phytosanitary status of bunches and berry color, without modifying technological parameters, and to enhance wine quality in different climatic conditions.