When the Dough is well kneaded, it is left to stand for some time, and then, as soon as it begins to swell, it is divided into loaves. After this process it is again left to stand, when it once more swells up, and manifests for the last time the symptoms of fermentation. It is then put into a hot oven, where the water contained in the dough is partly evaporated, and the loaves swell up again, while a yellow crust begins to form upon the surface. When the bread is sufficiently baked, the bottom crust is hard and resonant if struck with the knuckles, and the crumb is elastic, rising again in its place if pressed with the fingers. It will take from 30 to 45 minutes to bake in an ordinary oven, according to the size of the loaves, but a full 2-lb. loaf will never bake in less than 45 minutes, and if the oven is not over-hot a much longer time is necessary.
New Bread.—One word as to the unwholesomeness of new bread and hot rolls. When bread is taken out of the oven it is full of moisture; the starch is held together, and the bread, instead of being crushed so as to expose each grain of starch to the saliva, is formed by the teeth into leathery, poreless masses, which are highly indigestible. Bread should always be at least a day old before it is eaten; and, if properly made, and kept in a cool place, ought to be perfectly soft and palatable at the end of 3 or 4 days; and so firmly was this believed to be the case, that an Act of Parliament was once passed making it illegal to sell bread that was less than 24 hours old.
Baking-powder is largely used to vesiculate bread and cakes. The carbonic acid gas in this case is formed by the effervescence of bicarbonate of soda with some acid, usually tartaric, but sometimes hydrochloric. Many different kinds are sold, but each differs but slightly from the other. Some are coloured yellow and are known as egg-powder; some go by the name of yeast-powder; but the action of all is practically the same. A common recipe for home-made baking-powder is 10 ozs. of ground rice, 9 ozs. of carbonate of soda, 5 ozs. of tartaric acid, well mixed and sifted together; the rice is merely used to increase the bulk, and so to facilitate its mixing with the flour. If a teaspoonful of this or any other baking-powder is put in a tumbler of water, if effervesces rapidly; presently the effervescence subsides, and there remains water, with the rice undissolved, and some tartrate of soda. In the same way it effervesces in a cake, or in dough, and bubbles up exactly as in the case of the water. As the water soon subsided, so will the dough, the gas will escape, and there will remain flour, water, and tartrate of soda settled down into a solid mass. Such is the action of baking-powder on bread or pastry, if the latter is not baked at once. The whole value of the powder is lost. But if it is put in the oven while the gas is held in the dough, it will rise still further, because gas or air always expands with heat, and long before the gas escapes the dough will be baked into shape with all the bubbles in it,