This section is from the book "Mrs. Lincoln's Boston Cook Book", by Mary J. Lincoln. Also available from Amazon: Mrs. Lincoln's Boston Cook Book.
The Minnesota, or patent-process, flour is now considered one of the best grades. The Washburn, Pillsbury, and many other mills located in Minneapolis are the largest flour-mills in the world, and produce an excellent quality of flour, in which a large proportion of the gluten is retained. This Minnesota flour is made from carefully selected wheat grown in the Red River region, the best wheat-growing section in America. The first step in the process is the breaking off of the germinal point of each grain by what are called ending stones. Then it is sent through corrugated iron rollers, having shallow grooves cut spirally upon them, with rounded ridges between, and the opposing rollers grooved in an opposite direction. The grains are crushed (not ground); the starchy parts, or middlings, being quite finely powdered and easily separated from the bran or tailings. After this separation the middlings are passed through ten bolting-cloths, and then through other and finer corrugated machines, and made into the various grades of fine, superfine, and fancy flours.
A still better method of converting wheat into flour, and one which is indorsed By leading scientists and physicians, has been recently introduced by the Health Food Company of New York. Only the choicest kinds of wheat are used. The outer husk is first removed by moistening the grain, and subjecting it to a gentle rubbing by what is termed the "attrition process." This softens the woody fibre of the outer bran, which is easily removed by sifting, but does not affect the hard gluten coats. The grains are dried, then pulverized into various grades by a compressed cold-air blast, which dashes the grains into atoms with tremendous force. This is called whole-wheat flour, the name indicating that the whole of the gluten, or nutritive part of the flour, is retained. It is not sifted like other flours, but pulverized into all the varieties of crushed wheat, coarse granulated and fine granulated wheat; each variety, even the finest flour, containing all that is valuable as food. Bread made with this flour has been found, after repeated trial, to be sweet and agreeable to the taste, light and spongy in texture, with none of the objectionable features of Graham bread, and answering fully all the demands of perfect nutrition.
Cheap inferior Graham flour, made of poor flour mixed with bran, is worse than no food at all. Any flour containing much of the indigestible bran causes irritation of the digestive organs; all the food is hurried through the alimentaty canal before digestion is complete or all the nutriment can be absorbed, and thus is neither economical nor healthful. Fine flour containing the most gluten is the most nutritious, because it is all digested, and the loss of albuminous material can be supplied from other sources.
The Arlington, the Franklin, and some other brands of whole-wheat flour, are highly indorsed by those familiar with them.