Commercial red wines use the malolactic fermentation process to ensure stability from a microbiological point of view. In this second fermentation, malic acid is converted into L-lactic acid under controlled steps. However, this process is not free from possible collateral effects able to produce off-flavors, wine quality loss and human health problems. In warm viticulture regions such as the south of Spain, the risk of suffering a deviation during the malolactic fermentation process increases for the high must pH. This contributes to produce wines with high volatile acidity and biogenic amines. The work develops a method that comprises combining the use of two non-Saccharomyces yeast as an alternative to the traditional malolactic fermentation in specific difficult scenarios. In this method, malic acid is consumed by Schizosaccharomyces pombe, thus achieving the microbiological stabilization aim before bottling, while Lachancea thermotolerans produces lactic acid in order not to reduce and even increase the acidity of wines produced from low acidity musts. This technique reduces the risks inherent to the malolactic fermentation process when performed in warm regions with high potential alcohol degree and pH. The result is more fruity wines that contain less acetic acid and biogenic amines.
Author: Santiago Benito
Department of Chemistry and Food Technology, Polytechnic University of Madrid, Ciudad Universitaria S/N, 28040 Madrid, Spain