This International Standard describes the determination of the ? - amylase activity of cereals by the Falling Number method according to Hagberg-Perten. This method is applicable to cereal grains, in particular to wheat and rye and their respective flours, durum wheat and its semolina. For the purposes of this International Standard the term "flour" includes semolina and ground grain (whole meal), the particle sizes of which are defined. This method is not applicable for the determination of low levels of ? -amylase activity, which can be carried out in accordance with ISO 7973. 1.2 By converting the Falling Number 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 Falling Number values necessary to produce a sample of a required Falling Number.