Microvinifications in wild grapevine relic populations of Spain and France

Abstract

The microvinification of nine Eurasian wild grapevine populations situated in different habitats in La Rioja (Spain) and the Basque Country (Spain, France) were carried out. Populations were observed at flowering time in order to assess the presence of male and femal vines. Both harvests took place during the last week of October and the first week of November in 2015 and 2016. Bunches were destalked by hand selecting only ripe grapes, pressed and the amount of must in each sample was weighed. The mixture of must with seeds and skins were fermented at 20ºC with native yeasts without the addition of Potassium metabisulphite. The principal objective was to determine the main oenological characteristics of these wild wines. Due to the small size of the grapes and the fact that their seeds (1 or 2) are quite bulky, the volume of must obtained is very low in each microvinification (15.3 and 16.7 % in weight). In 2015, they showed higher values of alcoholic concentration, lower total acidity and higher pH than with the wines of the year 2016 because berries were more mature and healthier. On the other hand, the ethanol concentration lies between 6.5 and 9%. In both years, the total acidity values are high due to the elevated content of tartaric acid, situated between 5.3 and 7.2 g/l. The color intensity of wines presents high values, between 15 and 23. This is closely related to the high content of anthocyanins, between 470 and 531 mg/l and the high total polyphenols index, within the interval (65.8, 107). In all the samples both kinds of values are considered appropriate for young red wines. These wild wines may suggest that the wild grapevine is a very interesting phytogenetic resource. It might improve the acidity and color intensity of wines by crossing with red cultivars, a very important characteristics in the present context of climatic change, mainly in warming regions, such as the Mediterranean vineyards.