This International Standard specifies the determination of the a-amylase activity of cereals by the falling number (FN) method according to Hagberg-Perten. This method is applicable to cereal grains, in particular to wheat and rye and their flours, durum wheat and its semolina. For the purposes of this International Standard, the term "flour" includes semolina and ground grain (wholemeal), the particle sizes of which are defined. This method is not applicable to the determination of low levels of a-amylase activity. By converting the FN into a liquefaction number (LN), it is possible to use this method to estimate the composition of mixtures of grain, flour or semolina with known FNs necessary to produce a sample of a required FN.