Use of non-conventional yeasts to increase total acidity in the Cava base wines

Abstract

In recent years, climate change has strongly influenced viticulture, with a higher concentration of sugars in grapes, a lower concentration of organic acids and, therefore, increases in alcohol concentration and pH. This work aimed to increase the concentration of organic acids and total acidity in Cava base wine with different commercial strains: Saccharomyces cerevisiae (IO), a hybrid S. cerevisiae x S. uvarum (VE) and Lachancea thermotolerans (LA). Several laboratory and industrial fermentations were carried out with Macabeo must. Our results show that strains VE and LA are capable of producing high concentrations of succinic acid and lactic acid, respectively. The initial amount of nitrogen in grape must directly influences the production of these acids. By adopting different inoculation strategies, the co-inoculation of LA + VE brings about a significant increase in total wine acidity. The results also reveal that LA has excellent fermentative capacity when the initial SO2 concentration is low and the competitive ability of LA against the VE hybrid is good. In short, our results demonstrate that using strains LA and VE acts as a microbiological strategy to increase total acidity and to lower the pH of Cava base wines.