Sodium Chloride in Australian Grape Juice and Its Effect on Alcoholic and Malolactic Fermentation

Abstract

Elevated concentrations of sodium chloride (NaCl) are being observed in grape juice and wine, typically because of increasing soil and water salinity. There has been growing concern that the salt content of grapes may affect wine quality and the ability of yeast and bacteria to undertake fermentation and malolactic fermentation, respectively. This study evaluates the tolerance of Saccharomyces cerevisiae and Oenococcus oeni to salt in juice and wine by determining the duration of alcoholic fermentation and malolactic fermentation, culture viability, and metabolite production. Increased NaCl concentrations extended fermentation duration by S. cerevisiae and elevated concentrations of acetic acid and glycerol were observed. The effect of NaCl itself was not inhibitory to the O. oeni strains surveyed and in some cases appeared to enhance the extent of malic acid catabolism.