Controlling grape must fermentation in early winemaking phases: the role of electrochemical treatment.

Abstract

To contribute to an understanding of the phenomena related to the effect of low electric current (LEC) in grape must fermentation during laboratory and pilot plant scale winemaking, with selected co-culture yeasts (Saccharomyces cerevisiae strain 404 and Hanseniaspora guilliermodii strain 465). LEC (10, 30, 50 and 100 mA) was applied to fresh grape must as an alternative method to the usual addition of SO2. Parameters such as polarity, treatment duration (24-96 h) and type of inoculum yeast were varied one at a time. LEC decreased the survival time and increased the death rate of H. guilliermondii strain 465 in co-cultures, whereas it did not affect the growth and survival of S. cerevisiae strain 40. A final comparison was made of the main physico-chemical parameters on wine obtained after the different tests. The results have demonstrated that the low voltage treatment using a pair of graphite electrodes had a positive effect on grape juice fermentation (yeast microflora) during the early stages of winemaking, even with the potential of being an alternative method to the usual addition of SO2. These results could be of significant importance in developing new winemaking technologies for an innovative yeast fermentation control process for 'biological wine'.