Tartaric and malic acids are the main components responsible for the ocidity of the grape must. The level is normally correlated with the physiological aspects of ripening grapes, with the preceding climate conditions, soil aspects and agronomic practice production. The tartaric / malic ratio is very important to determine the moment to harvest and to conduct the winemaking. The purpose of this work was to determine the concentration of tartaric and malic acids, and the tartaric/malic ratio in musts of principal grapes varieties used in the vinification in Bento Gonçalves-RS, Brazil. Eight one red grape musts were analysed: Cabernet Sauvignon, Cabernet Franc, Merlot and Isabel and 56 musts of white grapes: Chardonnay, Italic Riesling, Muscat and Niagara. Quantitative analysis was carried out by using HPLC. The values were submitted to analysis of mean comparison through the Tukey test. The results showed predominance of the tartaric acid in all musts analysed and lower level of two both acids in the american grape musts - Isabel and Niagara - compared with Vitis vinifera varieties.
grape; chemical composition; organic acids
