The effect of magnesium ions during beer fermentation.

When cells of Saccharomyces cerevisiae ale strain C1028 were grown aerobically, ethanol production displayed a hyperbolic increase over a limited range of magnesium concentrations up to approximately 0.7 mM. Entry of cells into the stationary growth phase and the time of maximum ethanol and minimum sugar concentrations correlated with a period of maximum Mg2+ concentration in the growing media. It is suggested that magnesium accumulation by yeast cells may be usefully exploited in biotechnology concerned with the production of beer.