The hard wheats contain a larger proportion of gluten, and therefore a smaller proportion of starch than do the soft wheats. Wheat from which macaroni is manufactured, is an exceedingly hard variety. Successful attempts have been made within a few years to grow macaroni wheats in this country, and much of it is now produced in Dakota. Though hard wheat is used chiefly for making pastes like macaroni, excellent bread can be made from it also, as is shown by experiments made at the So Dakota Agricultural College.
THE PRINCIPAL GRAINS. (Redrawn from Com Plants).
Winter wheats as a rule are softer than spring wheats. So-called pastry flour is made from the softer wheats. Much of our bread flour is now made from mixtures of winter and spring wheat, and great care is exercised in the combining of these in order to keep an even standard.
The process of manufacturing flour is carried out differently by different manufacturers, so far as its details are concerned, but the main features are the same. The wheat as it comes to the mill is first of all cleaned, by screening to get rid of any large foreign substances that may be present in it, and by "scouring" to get rid of the fine dirt that may adhere. The next process is that known as breaking. The wheat is cut by corrugated iron rollers provided for the purpose.
Section of a Grain of Wheat.
From a Maine Exp. Station Bulletin.
There are generally five breaks in all. Each "break" is put through a number of siftings. The meshes of the bolting cloth through which this sifting is done are graduated in size, and the products accordingly vary in fineness. The finest particles are called the dustings, the coarsest are the scalpings, while between these are the middlings, - germ, medium and fine. The scalpings from the first break undergo a second breaking and are again separated by sifting as in the first break, and this process continues through all the breaks.
SECTIONS OF A WHEAT GRAIN SHOWING THE STRUCTURE AND DIFFERENT PARTS.
(From Original Drawings).
The flours on the market are made from mixtures of the products of the different breaks. When a flour is mixed it is tested by making a portion of it into a small loaf and baking it, and comparing this loaf with that made from some standard flour. The scalpings from the last break constitute the bran. This is almost wholly cellulose and is therefore not digestible by human beings, but much of the so-called Graham flour on the market is simply a mixture of white flour with some of this bran. True Graham flour is really wheat meal made by grinding the entire kernel.