Page:Encyclopædia Britannica, Ninth Edition, v. 3.djvu/268

Unvesiculated Bread.—The simplest form of bread, and the rudest baking, are seen in the Australian " Damper," a cake made from dough composed of flour, salt, and water, baked in the dying embers of a wood fire. The dough is laid on a flat stone, covered with a tin plate, and the hot ashes heaped around and over it, care being taken not to expose it to a heat of more than 212 Fahr. Pass over cakes, scones, and " bannocks " are prepared from a similar dough, and fired on hot plates or in ovens, and form an agreeable and nutritious food. When such dough is exposed to a high heat, so that the resulting cake is hard, dry, and resonant, biscuits (bis cuit, twice baked) are formed.

Biscuit Manufacture.—Biscuit making is a branch of trade distinct from ordinary baking, conducted under different conditions, and requiring machinery and processes peculiar to itself. Biscuits are made by a rapid and con tinuous process ; they can be preserved a long time, and in proportion to their price they occupy little space, so that it is practicable to sell them in markets remote from the place of manufacture. The manufacture of biscuits is now conducted on a very large scale, ingenious and complicated machinery is employed in the various processes, and a large export trade in biscuits has grown up. The firm of Messrs Carr & Co., of Carlisle, was the first to originate the manu facture, and that firm still possesses one of the largest and best-appointed establishments. To the partners of this firm we are indebted for much information as to the pro cesses employed in this modern industry.

FIG. 1. Sectional view of Shin-B

The general arrangements of a ship-biscuit factory arc shown in the sectional view, fig. 1. The flour stored on the upper floor is passed down through a shoot to the flour-room, where it is sifted to free it from knots or lumps. In the making of plain water or ship biscuits, the flour is shot directly down into the mixer a, on the ground floor, in quantities usually of one bag at a time, to which the requi site quantity of water, regulated by a gauge-glass, is added. The mixer is a cylindrical vessel of cast-iron, in which a series of knives or arms is kept revolving on a central axis. The revolution of these knives is sufficient to incorporate the flour and water thoroughly into a very stiff dough in about seven minutes. From the mixer the dough is de livered on a table in large amorphous masses, and it is next carried forward to the brake machine b. The brake consists of two heavy iron rollers, having generally a re ciprocating motion, between which the dough is passed backwards and forwards several times till it is rolled out into a plate or sheet of uniform thickness and consistency. The sheet of prepared dough is next carried forward to the cutting and panning machine c, a highly complex aud ingenious apparatus, the principle of which is shown in fig. 2. In this machine the dough is first passed between a pair of gaxige rollers a, graduated to secure a sheet of any desired tiniform thickness, from which it is received on an endless sheet of felt b. On this web the sheet of dough is carried forward by intermittent motion to a punch ing apparatus c, in which moulds or cutting edges of the size and form of biscuit desired are arranged. Here the biscuits are cut out, the scrap being caught on a web d, and carried upward till it falls over in a box or trough on the table e, from which it is returned to the brake machine. The biscuits are carried down the web /, and fall into tin trays, which are fed in at g by a boy, and move forward at the same rate the biscuit web travels, so that they are ready for being immediately placed on the travelling stage of the patent oven. The processes are so arranged that the oven carries forward the biscuits as quickly as they are delivered by the cutting machine, and in some cases the ovens are fed direct from the cutting and panning appa ratus by automatic machinery. The patent travelling ovens are constructed from 30 to 44 feet long, and fitted with endless webs either of plates or chains. The chain webs are used for baking small and fancy biscuits, such as are placed in trays, and the plates are used for large and plain water biscuits, which are placed by hand on the travelling plates. The rates at which biscuits of different sizes and degrees of richness must traverse the whole length of the oven varies from about five to forty minutes, and the tem perature of the oven has also to be modified to suit the various qualities. Both the heat and rate of motion are under easy and adequate control in the patent ovens.

FIG. 2. Cutting and Panning Machine.

There is an endless variety in the form and composition

of plain and fancy biscuits. In the trade list of Messrs Vicars, of Liverpool, the chief manufacturers of biscuit machinery, the names of 128 varieties of cutters arc men tioned. In the making of fancy biscuits, milk, eggs, sugar, butter or lard, and flavouring essences are extensively used, and in these cases the proportions of the various ingredi ents are roughly mingled before being sent down the shoot into the mixer. The richest class of biscuits, the dough for which is necessarily soft, are cut out by hand labour, and fired on trays in common ovens. The dough for rout biscuits is placed in a strong metal box or cham ber in which a piston is tightly fitted. The piston is moved forward by a screw, and it pushes the dough through a series of holes or dies. The dough is received on a sliding board, and is cut into proper lengths by a knife. Cracknels are made without either milk or water being used to mix the dough, eggs alone being employed for this purpose. Certain proportions of butter, sugar, and sesquicarbonate of ammonia are added to the mixture of flour and eggs, and the dough is baked in the usual way. The cracknels, when cut out, are thrown into a boiler of boiling water, and in about two minutes they float to the top. They arc then fished out and thrown into cold water, and then drained on cloths, panned, and fired in an ordinary oven at a high heat. In the firing, the ainmonic carbonate, being very volatile, is driven off, and the cracknel thus assumes its spongy structure. Many other varieties of biscuits are rendered light and spongiform by the use of the sesqui carbonate of ammonia, or of carbonate of soda, in conjunc tion with sour milk. In the firing of biscuits, not only

the moisture of the dough is driven off, but a certain pro-