Climate effect on ripening process in Vitis vinifera, L. cv. Cencibel

A seven years survey (2003 to 2009) has been carried out over old traditional vineyards cv. Cencibel in La Mancha region (Spain). Seven plots with more than 35 years old were sampled from veraison to harvest, measuring soluble solids (ºBaumé) and acid concentration (g/l in tartaric acid). The ripening process was different each year depending on season climate character (vintage). The monthly mean temperatures (April to September) and the rainfalls accumulated (April to September) have been studied and these factors have been related with the date of vintage and the colour intensity (very important parameter for wine quality). The growing-degree day (GDD) for the variety Cencibel (1551,1ºC) has been calculated.
The temperature of May is critical for the development of photosynthetic apparatus of the vineyard and thus, conditions all the ripening process. It has been found two different models of vintage: mild-fresh year (2004, 2007 and 2008) and warm year (2003, 2005, 2006 and 2009). In the warm conditions of La Mancha it is very desirable a delay in the ripening process. As the later will be the process, the cooler will be the nights at the end of ripening. This will improve the quality of the vintage, as it happened in the fresh years.