After the old barm is added to the new, in a few hours a scum gathers on the top. This scum will either start at the side of the tub and work gradually to the other side, or I have seen it start in the middle and work itself slowly to the sides of the tub. When ready it should have a nice clear bell top. It takes from ten to twelve hours to work before it is ready.
By following this method one may always have good barm. Cleanliness is very essential for barm, and care should be taken that neither grease nor churned milk shall get near it. We need scarcely say that experience is required in this as in other things.
American Patent Yeast.
I may add the following recipe for American patent yeast:—Take half a pound of hops and two pailfuls of water; mix and boil them till the liquid is reduced one half; strain the decoction into a tub, and when luke-warm add half a peck of malt. In the meantime, put the strained-off hops again into two pailfuls of water, and boil as before till they are reduced one half; strain the liquid while hot into a tub. (The heat will not injuriously affect malt previously mixed with tepid water.) When the liquid has cooled down to about blood heat, strain off the malt and add to the liquor two quarts of patent yeast set apart from the previous making by the above process. Five gallons of good yeast may thus be made which will be ready for use the day after it is made. It takes about eight hours’ time to manufacture, but gives very little trouble to the baker.
Good or Bad Flour.
Experience is also necessary to judge of flour; but any one in the habit of using flour may form a pretty accurate idea whether it is good or bad. If fine and white, it may be considered good so far as colour is concerned; but if it be brown, it shows that it was either made from inferior wheat, or has been coarsely dressed—that is, that it contains particles of bran. However, brown flour may be of a good sound quality, and fine white flour may not.
To judge of flour, take a portion in your hand and press it firmly between the thumb and forefinger, at the same time rubbing it gently for the purpose of making a level surface upon the flour; or take a watch with a smooth back and press it firmly on the flour. By this means its colour may be ascertained by observing the pressed or smooth surface. If the flour feels loose and lively in the hand, it is of good quality; if it feels dead or damp, or, in other words, clammy, it is decidedly bad. Flour ought to be a week or two old before being used.
Alum in Bread.
A common custom to improve flour was to add a small quantity of alum to a sack of flour—a custom which, it may be hoped, is entirely a thing of the past. According to Liebig, the action of alum in the process of bread-making is to form certain insoluble combinations which render digestion difficult, and detract largely from the value of bread as food. Professor Vaughan, of the University of Michigan, says: “The use of alum is an adulteration which is injurious to health. It unites with the phosphates in the bread, rendering them insoluble, and preventing their digestion and absorption. In this way, alum, when present, diminishes the nutritive value of bread. While some gain may perhaps temporarily accrue to the manufacturer through the covert perpetration of this fraud, still no good to any one can result therefrom.”