Pea Bread may be made in the same manner as directed in the foregoing article for beans ; it is sometimes mixed up with oatmeal and made into cakes ; but equal quantities of pea flour (that has been steeped), potatoe flour, and seconds wheat flour, afford a good bread. The sponge should be set with the wheat flour, and after fermentation the other flours kneaded in, allowed time to prove, then divided and baked.
Potatoe Bread.—Pare the potatoes, boil them well, beat them to a pulp, and knead with double their weight of wheat flour, adding a sufficient quantity of yeast and salt; ferment, make up, and bake. The introduction of potatoes in moderate quantity into the best wheaten bread is by no means prejudicial to its quality. We believe that most persons find such bread, when well made, more palatable than that which contains none. It is riot quite so dry, when new, as wheat flour alone ; it retains its moisture much longer, and will keep for ten days without any trace of sourness. The following is the process employed by most bakers for introducing them : A cask is prepared by boring holes in its bottom ; and the bottom made to fit into the mouth of a boiler containing water.
If the quantity of flour to be baked be four cwt., the quantity of potatoes that can be properly used is five stone. The potatoes are thrown into the cask, a cover is applied, the water is made to boil, and the steam ascending through the holes of the cask boils the potatoes. The boiling is continued until the potatoes crack and become mealy. They are then withdrawn, and are pounded with a wooden instrument until they become quite fine. While this potatoe meal is still very hot, cold water is eAded in such quantity as to reduce the whole to the thickness of butter milk. To this liquid, still warm, a gallon of yeast is to be added. A fermentation commences ; and after it has continued sufficiently long, during which the potatoe-meal rises to the top and forms a tough mass, the whole is to be well mixed; and being now a homogeneous liquid, it is to be strained, first through a coarse hair sieve, and afterwards through a finer. To this strained matter, one half of the whole quantity of flour is to be added, and well worked up with the hands so as to form sponge. When the sponge has duly fermented, the other half of the flour is to be added, along with some more water holding salt dissolved: this mixture is to be worked up into dough, and treated in the usual manner. An extremely light and beautiful bread is made by the introduction of the pure starch of the potatoe, in various proportions (to the extent of one fifth part), to wheaten flour. The best mode of separating this starch from the root with which we are acquainted, is by the employment of a simple machine that we contrived for the purpose many years ago, engravings of which are given in the next page. Fig. represents a vertical section of the machine. Fig. 2 is a perspective view of the grinding cylinder, with a part of the perforated covering turned back, to show the internal construction ; a a is a strong square frame or stand, made of wood; b, a square cistern containing water, under which the grinding cylinder c is partly immersed ; this cylinder, shewn separately in 2, is 11 inches in diameter, and 24 inches long ; it is covered with a sheet of iron e, perforated throughout with small holes, produced by means of a steel punch, having a quadrangular pyramidical point, which raises four distinct burs or teeth, particularly adapted to the purpose of rasping ; this perforated plate is nailed to the peripheries of four turned discs of wood, which thus produce the cylindrical figure, and each disc has a series of large holes d made through it, for the free passage of the water throughout the cylinder. The axis is mounted in plummer blocks, fixed on the frame, (not seen in the drawing,) and is turned by a winch handle f, or any other convenient means. G is a fly wheel, to equalise the motion. The potatoes are put into a hopper h, the lower extremity of which is formed into a square frame which encompasses the upper half of the cylinder in an exact manner, but not so as to touch it, in order that it may turn round freely. The hopper is also provided with a movable curved por tion i, turning upon a joint, and serves to press the potatoes r against the cylin der, as the latter is turned round by the agency of a lever k, on which a weight is suspended,—a traversing weight to vary the pressure. The curved side of the hopper is made of sheet iron, and has a long slit in the middle to allow the lever k to traverse, and as a guide to it. In setting this machine to work, the hopper is to be filled with potatoes washed perfectly clean, and the cistern is to be about two thirds filled with water, or so that the cylinder clips two or three inches into it. The weight being then applied to the lever k, the opera tion of grinding is commenced., and continued until the cistern is nearly filled with the pulp ; but before this takes place, the water in the cistern rises so much that a portion of it must be run off, or ladled out into another vessel, as the water which is not then clear contains a portion of the finest starch, that takes an hour or more to subside. The grinding of a bushel of potatoes into pulp by a machine of this size takes a man about a quarter of an hour, from which fact it will be seen, that one horse power is adequate to the reduction of about 24 bushels per hour. The next process to grinding down is the sepa ration of the starch from the fibre, and other extraneous parts. For this pur pose, the cistern, which is upon rollers, is drawn forward out of its situation about 6 inches, which allows sufficient room for the pulp being emptied out by means of a bowl into a sieve ; or instead of the latter, into a piece of lawn z stretched over a tall tub, (the best form of which, is, that of the inverted frustrum of a cone ;) the lawn being tied down by a cord passing round beneath a hoop on the to of the tub. The operation is thus performed; a bowl Sul of the pulp is first thrown on the strainer, (which is rendered concave by the pressure,) and immediately another bowlful of clear water, from a reservoir at hand, is dashed down upon the former ; the dilution which it thus receives causes the starch to pass rapidly through the strainer, this effect being increased by the operator continually stirring up the mixture with his left hand. A small portion of starch remains after the first allusion, but which is entirely removed by a second dose; the fibrous remains are then cleared off the strainer, and a fresh portion of the pulp from the cistern is thrown on the filter, and treated as the former, and the operation thus continued until the cistern is emptied. The cistern is again filled with water as before, the hopper reple nished with potatoes, and thus the grinding and washing away of the starch is alternately performed : this variation in the process affording the man an agreeable change from the labour of turning the mill. It is advisable to use two tall tubs like that already described, and to employ them alternately ; which will afford sufficient time for the starch to settle at the bottom of each in a solid cake, while the process is being continued with the other tub. About
four inches above the bottom of each tub there should be a stop-cock to draw off the supernatant liquid, which is of a reddish brown colour. The starch should•next be removed from the bottoms of the tubs, (as it is inclined in warm weather to undergo very soon the acetous fermentation, whilst wet, with the coloured water deposited between its particles,) and placed in large glazed pans, wherein it should be washed or stirred up again with fresh water, and allowed to settle again in solid cakes ; and this operation should be repeated until the water runs off colourless, which will usually be at the third or fourth time of drawing off. The starch then settles quickly into a firm and beautifully white cake. It has next to be dried, which is preferably done in the open air, or exposed to the rays of the sun, in a situation free from dust. The mass should be made into lumps with the fingers, and spread out on rectangular frames of wood, over which is stretched any cheap cloth : these, from their form, are very portable, and stand well upon one another, like the frames used by glue boilers for drying their manufacture. When thoroughly dry, it may be stowed away into casks ; and if kept unexposed to damp, may be preserved good for a century. In constructing an apparatus for conducting this manufacture on a large scale, many improvements on the foregoing might be made to expedite the work and facilitate the labour, which are too obvious to need our entering further into thersubject. It is, however, due to Mr. Whately, of Cork, to observe that that gentleman had invented a machine very similar to the foregoing, some time previous to its publication, but unknown to the author. The difference between the two machines is quite immaterial, excepting that in Mr. Whately's the grinding cylinder works out of water, which renders it liable to clog up,---an effect which is prevented by the arrangement of the other. In a communication made by Mr. Whately to the Society of Arts, (who presented him with their honorary gold medal for the invention,) he states, that " it is capable of the most satisfactory proof that the same quantity of land will yield above one-half more of farina, or flour, where potatoes are cultivated, than if the same quantity of land was applied to the production of wheat." He further states, " I have proved from experiment, that 2,619 lbs. of pure farina, or flour, may be produced from an acre of land planted with potatoes, and only 1,60016s. of flour from an acre of wheat. It will therefore be obvious, that if we can apply this great excess to the same purposes as the flour of wheat, the advan tages arising from it will be of the greatest importance to the community." It is, besides, well known that many poor light soils, which are considered unfit for the cultivation of wheat, will produce good potatoes abundantly. The cost of producing potatoe flour from the root, Mr. Whately estimates at only half that of obtaining the flour from the wheat. In the introduction of a small portion of potatoe flour in the manufacture of sea-biscuit, it is said the quality is mate rially improved, and that they will keep good for a much longer period of time; and it may be fairly urged, that if potatoes in the gross improve (as it is gene rally admitted they do) the quality of wheat bread, that they must be still more beneficial when deprived of the refuse matter they contain. This article is, nevertheless, considered legally as an adulteration bread, as well as many others, some of which we shall proceed to notice. The most common sophis tication in bread is alum. Some writers state that as much as 4 oz. are put into every quartern loaf by the public bakers ; but bread containing so large a quantity could not be eaten without serious constipation. From the best information afforded to us, we are inclined to believe the quantity of alum varies with the quality of the flour, the worst flour receiving the most alum to improve the colour ; and that the quantity put to a sack of flour (though it varies from 4 oz. to 4 lbs.) is usually about 2 lbs. ; and as this will assign to each 4 lb. loaf nearly oz., it is very probable the before-mentioned statement of 4 oz. to each loaf arose from an uncorrected error of the press. It has been asserted that bones burned to whiteness, and ground to an impalpable powder, are used to adulterate thirds flour ; this we trust, however, is a very rare occur rence. Chalk and whiting, in small quantity, are also, it is said, sometimes mixed with flour. Salt, although a necessary ingredient in bread, is sometimes added to such an excess that it becomes an adulteration ; the object attained by it is the causing the bread to retain a portion of the water which, without it, would be evaporated in the process of baking. If bread contain an unusual proportion of starch, it absorbs and retains more water from that cause. Such bread, therefore, is deficient in solid matter, and is technically termed hungry bread, as an equal bulk and weight does not satisfy the appetite like bread which holds less water. The bakers prefer flour that has been made about three months, or such a mixture of old and new flour as will make an equi valent. Weak inferior flour requires the dough to be made up as dry as possible. If the usual quantity of water required for the best flour be used, there is a liability to the fermentation running into the acetous stage, which of course renders the bread sour. In all cases, if the dough has been made too soft, it should be cooler than usual, otherwise the high heat of the oven quickly forms a crust imperviable to vapour, and thus locks up the water in the bread. Bread in this state is very common amongst the home-made, for want of due experience in the operator. In the employment of flour made from wheat that has undergone germination, it becomes necessary to have recourse to some extraordinary means to render the bread light. Mr. E. Davy, who made many experiments with a view to determine the best remedy for such malted flour, ascertained that the carbonate of magnesia of the shops, when well mixed with the new flour, in the proportion of from 20 to 40 grains to 1 lb. of flour, materially improves it for the purpose of making bread. Loaves made with it rise well in the even ; they are light and spongy, and keep well. To the worst flour as much as 40 grains may be added to 1 lb. of flour. Care should be taken to mix them inti mately together. When too little yeast has been added to the dough, the fermen tation is slow and incomplete ; when it has been added in too great a quantity, the fermentation becomes too rapid, and renders it liable to sourness; to remedy which, Mr. Chaptel has recommended the kneading up some carbonate of potash with the dough, which neutralizes the excess of acid. Dividing the dough into small masses, and exposing it to the air, also has a tendency to check the fermen tation. Under the several beads of CORN, Douon, MILL, OVEN, 8:c. a variety of improvements in the mechanism and processes of making bread will be found.