Acidification of musts in warm regions with tartaric acid and calcium sulfate at industrial scale

¹ Departamento de Ingeniería Química y Tecnología de Alimentos, Universidad de Cádiz, Campus Universitario de Puerto Real, C/República Saharaui s/n, 11510, Puerto Real, Cádiz, Spain
² Departamento de Química Analítica, Facultad de Ciencias, Universidad de Cádiz, Campus Universitario de Puerto Real, C/República Saharaui s/n, 11510, Puerto Real, Cádiz, Spain
³ Bodegas González-Byass, C/Manuel María González, 12, 11403 Jerez, Spain
⁴ Bodegas Garvey, Complejo Bellavista, Carretera Ronda Circunvalación, s/n, 11407 Jerez, Spain

Abstract

Acidification of musts is necessary in warm areas where high temperatures during ripening accelerate breathing com- bustion of tartaric acid and, in particular, malic acid in the berries. L(+) tartaric acid, L(-) or D,L malic acid and lactic acids are the only chemical acidifiers authorized by the OIV and European Community regulations. The use of calcium sulfate (gypsum: CaSO₄·2H₂O) is also authorized in the European Community as a complementary acidifier in generous and generous liquor 42 wines from Spain (a practice known as plastering), provided that the residual sulfate content in the wine does not exceed 2.5 g/L expressed as potassium sulfate. However, this practice is not yet approved by OIV. To predict the effect on pH of different acidi- fiers, several chemical modeling approaches have been described in the literature, in particular a simplified model where the acidity of wine is considered to be due to a monoprotic acid. The aim of this work is to verify this model at pilot and industrial scale in the acidification of musts with tartaric and calcium sulfate, added either individually and in combination, using doses up to 3 g/L and to study the modifications that these practices produce on the compositions of the resulting wines. This work sup- plies useful information to study this practice in OIV in order to consider its approval.