The ordinary method of bread-making in London is as follows: The first process, when the bread is made with thick yeast, being to prepare a mixture of potatoes, yeast, and flour, by which the process of fermentation is to be produced in the dough.

Mr. George W. Austin, in his pamphlet on Bread, Baking, and Bakers,’ says about the ferment: ‘For each sack of flour (280 lbs.) about 8 lbs. or 10 lbs. of dry, mealy potatoes are taken, well boiled and mashed and washed through a strainer to take away the skin; to this is added 12 or 14 quarts of water, at a temperature varying from 80 deg. to 90 deg., and a quart of thick brewers’ yeast, or 1 lb. of compressed yeast—which is equal. Having well dissolved the yeast, and added 2 lbs. of flour, the mass is allowed to stand some three or four hours, until the head falls in through the escape of gas.’ The next process is the preparation of the sponge. The trough and flour being ready, the ferment is taken, and, with the addition of 28 quarts of clear water, at a temperature of 80 deg. to 90 deg., is passed into the trough through a sieve or strainer, and the mass, being kept well together, is made up into a nice dry sponge. It is allowed to remain thus and ferment for another five or six hours, when it will have risen and formed a head, which is allowed to break. As soon as this head is broken it commences to rise again, and as124 soon as it has broken the second time the remainder of the flour is added, and the dough made as follows:

Two and a half pounds of salt dissolved in 28 quarts of clear water, at a temperature of 80 deg., and mixed well into what is termed ‘the sponge,’ with the remainder of the flour, the whole being broken up and well and thoroughly mixed and kneaded until the dough is uniform in material and consistency. It is then left to rise for another hour or more, when the dough is weighed out in pieces of the requisite size and speedily manipulated into the required shape. As the loaves are moulded they are placed on trays, covered with a light cloth (to prevent the dry and colder air forming a dry crust on the surface), and left to dry sufficiently before being placed in the oven. Before this is done the loaves are slightly brushed over with a small quantity of milk and water to improve the appearance of the outside of the loaf when it comes from the oven.

The oven is, for the purpose of baking bread, brought up to a heat of 400 deg. Fahr., and the bread, although seemingly baked by dry heat, is in reality boiled in the steam of the water which the bread contains.14

125

Salt is added to make the bread more palatable; but it has also another effect. With inferior flour dextrin is formed inside the loaf to some extent as well as on the outside, consequently bread made from inferior flour rises badly and is darker in colour. This inferior flour is made sometimes from wheat that has been damp, the dampness causing the soluble albumenoids which the grain contains to act on the insoluble gluten, decomposing it into soluble bodies, and producing dextrin by their action on the starch in the grain. The further decomposition of these albumenoids is checked by the action of the salt during the fermentation of the bread.

And now it will be well to say something about the leaven of bread. We have already seen the modern method of making a ferment with flour, potatoes, and brewer’s yeast; but there are other substances which do not cause fermentation, and yet lighten the bread, such as the different baking powders, and the American sal eratus, a mixture of bi-carbonate of soda and salt. Carbonate of ammonia, which entirely evaporates in baking, is used in confectionery to raise the paste by the bubbles it forms in its volatilisation. The unfermented breads, such as those made by the late Dr. Dauglish’s patent (of which more anon), are rendered light upon the same principle, the usual method being to mix soda with the flour, and hydrochloric acid with the water, in the proportions in which they unite to form chloride of sodium, or common salt. The effervescence, like that produced in mixing seidlitz powders, converts the paste into a porous sponge, which, however,126 requires to be very quickly placed in the oven. The salt formed by the mixture replaces that ordinarily added to the dough in making bread; but this method is seldom used by practical bakers. Whatever, therefore, be the method by which bread is made light, the object to be attained is to pervade the dough with numerous cavities, which keep the particles of flour asunder, instead of forming a compact and unyielding mass.

The science which gave an insight into the cause of the ‘rising’ of bread, and suggested substitutes for the ordinary fermenting materials, is but of recent date. These ferments operate by generating an infinity of gas bubbles, which honeycomb the dough. The earliest process was to employ leaven, which is still largely used in the manufacture of the black rye bread of the Continent, and consists of dough which has become more or less sour by over-fermentation. This is kept from one baking to another, to inoculate a fresh bulk of paste with its fermenting influence. No sooner does it come into contact with the fresh dough than it communicates its own properties, as by contagion. Probably the discovery of leavening has, in many countries, been owing to accident, through neglected paste having been attacked by the fungus which is the cause of fermentation.

Many of my readers probably do not know that yeast is a plant. It belongs to the class of fungi, and, in accordance with the general habit of its kind, it differs from the green forms of vegetable life by feeding upon organic substances. The yeast plant represents one condition of a species of fungus re127markable for the diversity of forms it exhibits, its wide, nay, universal distribution, and the magnitude of the effects, sometimes beneficial, sometimes mischievous, which it is capable of producing. The forms in which it is familiar to most persons, although its nature may be unsuspected, are yeast, the gelatinous vinegar plant, the ‘mother’ of vinegar, and many decomposing vegetable infusions, and the common blue or green mould (penicillium glaucum) which occurs everywhere on sour paste, decaying fruits, and, in general, on all dead organic matters exposed to combined moisture and moderate heat.

Yeast and the vinegar plant are the forms in which it vegetates under various circumstances when well supplied with food. Mildew is its fruit, formed on the surfaces exposed to air at certain epochs, like the flowers and seeds of the higher plants, to enable it to diffuse itself, which it does most effectually, for the microscopic germs, invisible singly to the naked eye, are produced in myriads, and are so diminutive that ordinary motes floating in the atmosphere are large in comparison.

Yeast, when examined under the microscope, is found to consist of globular vesicles about 1/2300th part of an inch in diameter when fully grown. They are multiplied by little vesicles budding out from the sides of the parent. These soon acquire an equal size, and repeat the reproduction, either while attracted to the parent globule or after separating from it. The multiplication goes on to an indefinite extent with a fitting supply of food and at a moderately warm temperature (70 deg.-90 deg. Fahr.). The vesicles128 are nourished by sucking in a portion of the organic liquid in which they exist, decomposing this chemically, and either actually giving off, or causing the separation of their outer surface, of carbonic acid in the form of gas. To give a familiar illustration of the action of the carbonic acid which is evolved from yeast on the dough, I may say that it is analogous to the froth formed on a tumbler of bottled ale or ginger-beer. The cavities or bubbles in the dough are produced in an exactly similar manner; but two circumstances occur in bread to render them permanent—first, the fact that they are slowly formed; secondly, that they are generated in a substance which, while it is soft enough to allow the bubbles to expand, is tough enough to retain them.

There are several kinds of yeast besides barm, or brewer’s yeast, which, in spite of its bitter taste, is generally used by bakers because it is the least expensive. Next in consumption is what is termed press yeast, in German press hefe or pfund hefe, commonly known in commerce as German yeast, so called because it originally was a monopoly of that country, but it is now largely manufactured in Scotland. Of these yeasts Mr. Austin says:

‘Press yeast is obtained partly by the brewing of beer or distillation of spirits as a by-product, partly it is made artificially. In the former case, the beer upper yeast is mixed with ten times its quantity of water, to which one per cent. of carbonate of ammonia is added, macerated and well washed for an hour, and then mixed with a compound of two parts129 of finely-powdered malt and ten parts starch, so that we have a firm mass, which is made into cakes half-an-inch thick. This yeast must be made fresh every two or three days, and must be kept in a cool place. A better press yeast is made from the yeast of the distilleries. The pasty residue of the mash tub is passed through a hair sieve to get rid of the grain husks. The filtrate is allowed to settle, and the sediment is put into linen cloths and washed with water, and the water squeezed out again under gentle pressure. The yeast is thus obtained in the form of cakes.’

Very many people prefer to make their own bread instead of buying it from the baker; not that there is a gre............