The roles of certain metal ions (particularly Zn2+ and Ca2+) have long been recognized in brewing, but the involvement of Mg2+ and its interaction with other ions has not been fully investigated. In the present study, fermentations under conditions of altered Mg2+ and Ca2+ availability were conducted in several laboratory and industrial growth media using brewing, distilling, and winemaking strains of Saccharomyces cerevisiae. It was observed that some fermentation substrates such as wine must and molasses possess Mg:Ca concentration ratios that grossly favor Ca2+, and this is deemed to be detrimental to yeast growth and ethanol productivity through Ca2+ antagonism of essential biochemical functions of Mg2+. Therefore, by augmenting Mg:Ca ratios in growth media by Mg2+ supplementation, or by “preconditioning” cells in elevated levels of Mg2+, fermentation performance is enhanced both in terms of rate and yield of ethanol produced. Although malt wort generally contains higher Mg:Ca concentration ratios compared with other fermentation feedstocks, beneficial effects of added Mg2+ are, nevertheless, similarly observed. This indicates that brewers' wort may not be fully optimized with respect to the bioavailability of Mg2+ for maximal yeast performance.
|Number of pages||6|
|Journal||Journal of the American Society of Brewing Chemists|
|Publication status||Published - Jan 1996|