Changes in the ripening development of grapes in South Tyrolean viticulture according to the data of the annual ripeningtests from 1985 up to now

Abstract

Since 1985, the Laimburg Research Centre has been carrying out, on on a weekly (a few weeks before full ripening), a test on the most important South Tyrolean grape for the purpose of monitoring the ripening status and help winegrowers to plan their harvest. The resulting data represent at the same time an interesting documentation of the changes which occurred during this period. In addition to climate changes, with increasing average temperatures, the last three and a half decades in South Tyrol have been characterized by major changes in viticulture and, in particular, by the pursuit of higher grape and wine qua-lity. Today we register the same grape ripeness stage 19 to 50 days earlier than in 1985; the majority of cases has in average an about 3-weeks earlier ripening. It is not possible to determine from the available data to what extent these changes are due to the changing climatic conditions or changes in cultivation. However, the latter might also play a role, especially in cases with an above-average early ripening. At the same sugar content, the total acidity of musts did not decrease; likewise, the pH values did not increase. This should have been expected due to the warmer conditions du-ring the ripening period of the grapes. Rather, data show that, for the same sugar content, the total acidity values have either remained similar or are higher today than in the past. In some cases, with the same total acidity, the pH values are also lower today than in the past.