for wheat-flour. Their poverty in nitrogenous matter, or flesh-formers, is so great, that the greatly increased quantity required as food to support the body, apart from mere inconvenience, more than compensates for their apparent low price. Thus, good wheaten bread, at 2d. per lb., is more than twice as cheap as potatoes at 1d.; for, assuming 2 lbs. of the first as a day’s food, 10 lbs. of the last will be required for the same purpose; and even this large quantity will scarcely effect the desired object. Liebig has demonstrated that, regard being had to the nutritive power of wheat, it is, under all ordinary circumstances, the cheapest article of food provided by nature for man.
We have not entered into particulars respecting oven management, because, on the large scale, it is thoroughly understood by every practical baker. For the instruction of the busy housewife, however, we may state that the oven should always be sufficiently heated before the bread is put into it, in order that the gas contained in the cells of the ‘sponge’ may be expanded as rapidly as possible by the heat, and the resulting light mass quickly rendered sufficiently solid to prevent its subsequent collapse. The heat should also be maintained at nearly the same temperature during the whole of the time the bread is submitted to its action. In general, with ordinary kitchen ovens properly heated, 30 minutes’ baking is sufficient for one-pound loaves and cakes; and 15 minutes in addition for every pound after the first for larger ones. Thus, a 1 lb. loaf requires 1⁄2 hour; a 2 lb. loaf 3⁄4 hour; and a 4 lb. loaf, 11⁄4 hour.
It is the common ambition of the English baker to give that peculiar tint to the crust of his bread in the process of baking which is so highly esteemed by connoisseurs, and so successfully produced by the Viennese and Parisians. It has been long known at Vienna that if the hearth of an oven be cleaned with a moistened wisp of straw, the crust of bread baked in it immediately afterwards presents a beautiful yellow tint. It was thence inferred that this peculiarity depends on the vapour, which being condensed on the roof of the oven, falls back on the bread. At Paris, in order to secure with certainty so desirable an appearance, the hearth of the oven is generally laid so as to form an inclined plane, with a rise of about 11 inches in 3 feet; and the arched roof is built lower at the end nearest the door, as compared with the further extremity. When the oven is charged the entrance is closed with a wet bundle of straw. By this arrangement the steam is driven down on the bread, and a golden-yellow crust is given to it, as if it had been previously covered with the yolk of an egg.
Pure wheaten bread is one of the most wholesome articles of food, and has been justly termed the ‘staff of life,’ and a certain proportion of it should be taken at every meal.
New and Stale Bread.—As has been just stated, bread which has been kept for 24 hours after baking is more digestible, and therefore preferable to that which has been newly baked. This latter exhibits a well-known elastic appearance, and possesses a certain degree of moisture which renders its taste more agreeable to most persons than bread which has been kept for a day or two, and has become firmer and drier in appearance, and which is commonly termed stale. It is very generally supposed that this change in properties in bread which has been kept for a few days, is owing to the loss of water.
This, however, is not the case. The crum of newly baked bread when cold contains about 45 per cent. of water, and that of stale bread contains almost exactly the same proportion.
The difference in properties between the two is due simply to difference in molecular arrangement. Boussingault found that a loaf which had been kept for six days, though it had become very stale, had not lost more than 1 per cent. of its weight when new. The same loaf was then placed in the oven for an hour, and at the end of that time it had acquired all the properties and appearance of new bread, although during the second baking it lost 31⁄2 per cent. of water. In another experiment a portion of bread was allowed to become stale when enclosed in a tight case, to prevent loss of water by evaporation; it was then heated, and was thus restored to the condition of new bread; these effects were produced alternately, many times in succession, upon the same piece of bread; a heat of about 131° F. was found to be sufficient to convert stale into new bread. Every person who has seen a thick slice of stale bread toasted may have satisfied himself that the crum has during this operation been converted into the same condition as that of new bread.
Fungi. When bread has been kept a few days and has become stale, certain species of fungi show themselves in it: these are the penicillium glaucum, which is the green mould of cheese; the fermentum cerivisiæ or yeast fungus; the oidium auriantiacum or orange-red mould; the puccinia graminis and others. Excess of salt added to the bread prevents the development of these fungi.
Diseases arising from the employment of unsound Flour and Bread.—The flour may be ergotised or grown, and fermenting from the presence of fungi. All the poisonous symptoms of ergot are induced from continuously partaking of bread made with ergotised flour. Dry gangrene is one of the most virulent forms of poisoning caused by partaking of ergotised bread. Severe intestinal derangement is an accompaniment of the milder forms of poisoning. Ergot is more frequently present in rye flour than in wheat. Fermenting bread is a fertile source of dyspepsia, whilst acid bread causes diarrhœa. This latter malady is also caused by the presence in bread of the oidium
aurantiacum. Professors Varnell and Tuson state that mouldy oats, the mould being caused by a fungus (the aspergillus), have given rise to paralytic symptoms in horses, so that the presence of these fungi in oats used for making bread should always be regarded with considerable caution.