This method describes the viscometric determination of α-amylase in malt.
α-Amylase primarily brings about the degradation of starch to dextrins and thus contributes to liquefaction. In barley, its activity serves as an indicator for the progress of germination; in malt, it provides an indication of the time required to achieve a negative result for the iodine test during mashing and is thus considered an attribute one can employ to evaluate quality. Microbial enzyme preparations can also be evaluated on the basis of their α-amylase activity.
Malt intended for use in beer brewing or elsewhere in the food industry
While α-amylase is active in a gelatinized solution of amylopectin, the viscosity of the solution is constantly dropping due to the degradation of the starch molecules, which can be tracked using a rotational viscometer. The change in the reciprocal of the specific viscosity serves as a measure for the activity of α-amylase.