The old-fashioned way of making flour was to pulverize the wheat in one operation through mill stones; and then a crude separation of the flour and bran and other dark portions of the wheat berry was made by revolving reels covered with what is known as silk bolting cloth. Naturally, the separation was imperfect, and much of the brown portion remained in the flour.

Modern milling is what is known as a gradual reduction system, whereby the wheat is gradually and carefully reduced. The wheat is run through six systems of rolls, for the purpose of loosening the middlings. These middlings are then purified by means of sieves and air-suction machines, which remove all the brown portion of the berry. The middlings are, after purification, reduced to flour.

The wheat grain is thoroughly cleaned and scoured before the flour-making process begins.