Maturation curve and estimates of sugar content and titratable acidity as a function of degree-days: IAC 138-22 'Máximo' winegrape

The increasing importance of grape production for wine purposes in the State of São Paulo (Brazil) motivated the development of a field trial aiming at characterizing the maturation curve during summer and winter seasons for the grapevine IAC 138-22 'Máximo' grafted on the rootstock IAC 766 'Campinas' and trellised with upright branches. The total soluble solids (TSS) values were higher during the winter growing season (17.4 to 17.5 ºBrix) when compared to the summer growing season (14.2 to 15.6 ºBrix). The titratable acidity (ATT) was also higher during the winter growing season. Also, polynomial equations of second degree can be used to estimate the TSS and ATT as a function of accumulated degree-days starting at the beginning of maturation (véraison).

grapevine; total soluble solids; winter cycle