starch cells, and 5 or 6 layers of different-shaped cells surrounding the starch, each less starchy and less white than the centre, each containing more phosphates and getting browner as it is nearer to the outer covering of all, the bran. The gluten or flesh-forming material is in a row of brick-shaped cells near the starch. In grinding, these two portions are separated, and, the husk being blown away in the process of winnowing, the flour remains in the form of a light-brown powder. In order to separate the brown from the white, it undergoes a process called "bolting." It is passed through a series of fine sieves, which separate the coarser parts, leaving behind fine white flour—the "whites" or "supers" of the millers, flour dealers, or factors. It will thus be seen that the finest white flour comes from the centre of the grain, and contains a considerable proportion of starch. "Households," or "fines," is somewhat darker in colour because it takes in some of the cells rich in gluten, it is therefore more nourishing and, as a rule, stronger and more elastic in the dough, and will make a larger though sometimes a very holey loaf. "Sharps," "tails," "tippings" and "pollard" are all names given to the intermediate products between white flour and bran. These latter products are generally used to feed stock upon, but might with some probable advantage be added to bread, as they are very nourishing, and not indigestible like bran. This was the process generally in vogue for the production of flour fifty years ago, but at the present time a totally different process is followed, and the old-time stones have been replaced by steam rollers; hence the term now generally met with of "roller process flour," meaning that the wheat has been reduced to flour by rollers instead of ground as before described. There is also a good deal of difference in the products of the two systems, for although flour is the result of both, the roller flour is the better. The principal difference between the two processes is that by the roller process the flour is manufactured after the impurities have been got rid of, while in stone milling, as before stated, the whole grains are ground down into a general mass, and a portion of the impurities removed or taken out in the subsequent dressings or bolting of the meal.
The process of roller-milling can be divided into 5 stages:—1st. Cleaning the wheat; 2nd. The break-roller process; 3rd. Purification; 4th. Smooth-roller process; 5th. Flour dressing.
The first process consists of cleaning the grains and freeing them from foreign matter, and many ingenious machines are used for the purpose which need not be discussed here. The grain being cleaned, dried, or whatever preliminary operation is necessary, is fed into the break rolls. These are constructed of steel, fluted longitudinally, with a slight spool, and as the grains pass through they are crushed, and semolina middlings flour and offal are produced. Usually there are seven sets of rolls to each break, and the products from each break are sifted by sieves with different sized meshes, and the product is termed