Reduction of the alcohol content and pH of Pinot noir and Tannat red wines using grapes with different maturation level

The aim of this research was to determine the effectiveness of the mixture of the must of grapes with different degree of maturation to obtain Pinot Noir and Tannat wines with lower alcohol content and pH. In veraison, immature grape must was extracted and kept at 4 degrees C until its use. In technological maturity, the grapes harvested were destemmed, crushed and distributed in six containers. Three of them were vinified in a traditional way, while in the other three, 3 L of the mature grape must was substituted for 3 L of the immature grape must. Both treatments performed a fermentative maceration of 7 days. The basic wine composition, color, concentration of total phenols, anthocyanins, catechins and proanthocyanidins were determined two months after devatting. The substitution of must allowed the production of Pino noir and Tannat wines with lower alcohol content and pH without reducing the concentrations of total polyphenols, catechins or anthocyanins. The effect on the concentration of proanthocyanidins was variable according to the cultivar and year of harvest. The Tannat wines reduced in alcohol presented greater intensity of color, lower hue and similar chromaticity than the control wines.