What is the Falling Number of a flour and how is it measured What values should we specify for our flour miller

The Falling Number of a flour is related to the level of cereal a-amylase which is present. The production of cereal a-amylase is encouraged within the wheat grains if their moisture content is sufficiently high in the last few weeks before harvesting. Such conditions are most likely to happen if the period concerned is particularly wet.

The full name for the test is the Hagberg Falling Number test and it was originally developed in Sweden. It takes its name from the basis of the test. A flour-water suspension is heated within a tube held in a boiling water bath. The mixture is stirred for 60 s to ensure uniformity of the mixture. At the end of the stirring period the stirrer is brought to a predetermined point at the top of the tube, released and the time taken for the stirrer to fall through the mixture to a lower fixed point in the test tube is measured. The time taken for the stirrer to fall down the tube is known as the Falling Number.

The test is based on the action of the cereal a-amylase on the starch present in the flour. The temperature in the test is designed to give maximum enzymic activity in the flour-water mixture and quickly changes according to the level of cereal a-amylase present; the higher the cereal a-amylase level, the quicker the flour-water paste thins, the faster the stirrer falls and therefore the lower the Falling Number.

The higher the cereal a-amylase level, the greater the formation of dextrins during breadmaking and so the more likely that there could be problems with bread slicing. In bulk fermentation high cereal a-amylase levels will lead to dough softening.

The Falling Number includes the 60 s stirring time so that the lowest theoretical number is 60. In practice Falling Numbers over 250 are suitable for most breadmaking processes. As well as having too much cereal a-amylase activity it is possible to have too little and Falling Numbers above 350 indicate that the flour should be supplemented with a form of amylase (see 4.5). We suggest you specify that your Falling Number lies between 250 and 280, though the actual level you require will be specific to your products and processes.

Continue reading here: What is damaged starch in flour How is it damaged and how is it measured What is its importance in baking

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