Cereals processing technology

Wheat, corn and coarse grains milling 29
Fig. 3.1 French process flour mill flow sheet (Storck and Teague 1952).
Henry Simon, the Manchester-based milling engineer, perfected the gradual
reduction system in the 1870s. The main features of this milling technique were
the use of a large number of process stages in an extension of the French process
and the exclusive use of roller mills for grinding. The principles of gentle
grinding and intermediate sieving were developed upon to give the break,
purification and reduction systems that are used exclusively today.
Before the development of the long process using roller mills, stone mills and
shorter processes were normal. The advantage of the newer, more elaborate
process was that higher yields of quality flour could be produced. The older
processes employed can only be described as crude and produced typically only
10% high quality flour from the wheat berry compared to more than 70% in
roller milling plants. The remaining flour was of very poor quality and heavily
contaminated with the bran and germ constituents of the wheat berry.
Many variations in the detail of the process flow sheet emerged in the years
after the perfection of the gradual reduction system. This was due to the varying
requirements of customers and even political directives. For example, in
wartime, the British government ordered millers to produce high extraction flour
in order to extend supplies and to supplement people’s diet with the essential
vitamins and minerals found in the outer layers of the wheat berry (Smith 1938).
Development of flour milling technology since the introduction of roller mills
and the gradual reduction system include flow sheet alterations to accommodate
newer machine technologies and increased machine capacities as well as the
adoption of information-based technologies.