PROCESSING OF WHEAT – FLOUR

Flour is a finely ground powder prepared from grain or other starchy plant foods and used in baking. Although flour can be made from a wide variety of plants, the vast majority is made from wheat. The earliest methods used for producing flour all involved grinding grain between stones.

Grading the wheat

Wheat is received at the flour mill and inspected. Samples of wheat are taken for physical and chemical analysis. The wheat is graded based on several factors, the most important of which is the protein content. The wheat is stored in silos with wheat of the same grade until needed for milling.

Primary processing of wheat

Two methods of milling can be used for wheat, stone grinding and roller milling. Stone grinding is the traditional method of grinding the wheat between two large, heavy circular stones, where the top stone revolves on the lower one. The stones are grooved to assist in the grinding process. The final product is stone-ground wholemeal (or whole wheat) flour. Roller milling is the most common method of milling wheat. Roller milling involves the wheat being passed through a series of steel rollers, each rotating at a different speed. These crush the grain and separate the outer bran layer from the inner endosperm. The endosperm is passed through several more rollers, the wheat germ is removed and the final product is plain (white, refined) flour.

Processing the flour

Small amounts of bleaching agents and oxidizing agents are usually added to the flour after milling. Vitamins and minerals are added as required by law to produce enriched flour. Leavening agents and salt are added to produce self-rising flour. The flour is matured for one or two months.