To understand better the details of bread making, wheat, from which bread is principally made, should be considered.
A grain of wheat consists of (1) an outer covering or husk, which is always removed before milling; (2) bran coats, which contain mineral matter; (3) gluten, the proteid matter and fat; and (4) starch, the centre and largest part of the grain. Wheat is distinguished as white and soft, or red and hard. The former is known as winter wheat, having been sown in the fall, and living through the winter; the latter is known as spring wheat, having been sown in the spring. From winter wheat, pastry flour, sometimes called St. Louis, is made; from spring wheat, bread flour, also called Haxall. St. Louis flour takes its name from the old process of grinding; Haxall, from the name of the inventor of the new process. All flours are now milled by the same process. For difference in composition of wheat flours, consult table in Chapter VI on Cereals.
Wheat is milled for converting into flour by processes producing essentially the same results, all requiring cleansing, grinding, and bolting. Entire wheat flour has only the outer husk removed, the remainder of the kernel being finely ground. Graham flour, confounded with entire wheat, is too often found to be an inferior flour, mixed with coarse bran.
Grinding is accomplished by one of four systems: (1) low milling; (2) Hungarian system, or high milling; (3) roller milling; and (4) by a machine known as distintegrator.
In low milling process, grooved stones are employed for grinding. The stones are enclosed in a metal case, and provision is made within case for passage of air to prevent wheat from becoming overheated. The lower stone being permanently fixed, the upper stone being so balanced above it that grooves may exactly correspond, when upper stone rotates, sharp edges of grooves meet each other, and operate like a pair of scissors. By this process flour is made ready for bolting by one grinding.
In high milling process, grooved stones are employed, but are kept so far apart that at first the wheat is only bruised, and a series of grindings and siftings is necessary. This
