STUDY OF THE ACIDIFICATION OF SHERRY MUSTS WITH GYPSUM AND TARTARIC ACID

Must acidification is a necessary operation in hot regions due to the low natural acid content of the grapes grown there. Tartaric acid is w hat is most usually used for this purpose. Using gypsum (CaSO4.2H(2)O) allows the amount of tartaric acid needed to reach a given pH to be r educed. This paper is a study of the acidification of musts produced i n Sherry area (Southern Spain) to a pH of 3.25 with tartaric acid alon e and tartaric acid acting together with 2 g/L of gypsum. Using gypsum causes a reduction in must pH of approximately 0.2 units and allows t he tartaric acid dosage to be cut down by 1.5 to 2.5 g/L. The concentr ation of sulfates in the fermented wine lies below 2.5 g/L (the maximu m authorized by the European Community), and the calcium concentration is 130 mg/L. Both levels are compatible with a correct winemaking. Th e acid buffering power of the wine and the alkalinity of the ash are r educed by the use of gypsum, which makes later acidification easier. O ther wine component levels are not affected.