In the cane sugar industry commercial α-amylase is often added to the penultimate and final evaporators and other unit processes of factories to break down starch and is sometimes added to the refinery process as well. This method measures the relative activity of commercial α-amylases used in the sugarcane industry. The method is modified from the method of Novozymes Phadebas® α-amylase test to better fit sugar factory conditions. This method is applicable to commercial α-amylase as used in sugar cane processing and refining. Extensive within laboratory precision estimates have been made. For commercial α-amylases the difference between duplicate results should not be greater than 5% of the mean value.