Stability of α‐amylase in model brewery mashes

Experiments with model mashes, of partly purified malt α‐amylase added to a grist of ethanol‐extracted pale‐ale malt confirmed that decreasing the concentration of the mash or increasing mash temperature caused an acceleration in the rate of α‐amylase destruction. the experimental mashes were devoid of proteolytic activity and contained high levels of calcium ions. the mash temperature was below that needed to inactivate the enzyme in solution, so that the instability of the enzyme was unexpected. α‐Amylase was estimated by a convenient reducing power method using a reduced starch substrate, and ‘hollow plug’ accelerated ion exchange for the removal of interfering substances.