Pre-alcoholic fermentation acidification of red grape must using Lactobacillus plantarum.

Red grape musts from overripe grapes are characterised by high pH and sugar concentration. Corrections with organic acids are commonly used to secure the alcoholic fermentation and improve the organoleptic characteristics of the wine. In this study we test an alternative biological acidification method using the ability of Lactobacillus plantarum to produce high concentrations of lactic acid. The time course of sugars, organic acids and pH were measured. Available sugars were consumed by L. plantarum producing up to 8.3 g L(-1) of lactic acid. Lactic acid changed the pH from 3.9 to 3.4 after 14 days post-inoculation without yielding a relevant concentration of acetic acid (0.34 g L(-1)).