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This method determines the amount of alpha-amylase in malted cereal grains and cereal flours from sound and weather-damaged grains. Because the levels of alpha-amylase in flours from weather-damaged and sound grain are about 0.1% of that in malted grains, two assay formats are employed. For malted cereals, the enzyme is extracted with buffer and suitably diluted before assay. For flours from sound and weather-damaged grains, the assay is performed directly on flour slurries. In both formats, the activity is converted to Ceralpha units. This method is the only alpha-amylase procedure that employs a defined substrate (i.e., end-blocked p-nitrophenyl maltoheptaoside; in the presence of excess quantities of amyloglucosidase and alpha-glucosidase).The substrate employed is dyed and cross-linked amylose in tablet form. As the particles of substrate are hydrolyzed by alpha-amylase, soluble dyed fragments are released into solution, and the color released is directly related to the level of alpha-amylase in the assay mixture.