Soda Biscuta.— Wheat flour and water, salt and yeast, are mixed as in the manufacture of wheat bread. The dough is allowed to ferment for about 20 hours, in order to break down the gluten of the wheat entirely. During this pro longed fermentation, lactic acid acidity develops, this being the agency to break down the gluten. Now a sufficient amount of bicarbonate of soda is added to neutralize the acidity; at the same time carbonic acid gas is developed through the interaction of lactic acid and the bicarbonate of soda, both neutralizing one another, so that no acid taste nor soda taste is noticeable. In order to invigorate the fermentation, a small amount of malt extract is employed in mixing the dough.
For sweet soda biscuits and graham biscuits, an adequate amount of sugar is used in mixing. The finished dough is rolled out in flat sheets of the desired thickness. These are cut, or divided, the dough pieces placed in pans and baked.
Temperatures.— The temperature of a freshly mixed dough should be about 79 to During dough fermentation in its three stages, the temperature gradually rises to about 85° but should not exceed this. During the proofing stage, the temperature rises to about 90°. In the oven the temperature is maintained 400 to 500° F. but the temperature in the interior of the loaf does not reach a higher degree than about 110 112. (A new bake may be made in the same oven in case of emergency each hour, but generally the oven is recharged every second hour). After taking the bread from the oven it is placed on the cooling racks, where the loaves rest in compartments provided with screen bot toms, on which the loaves are placed to allow of cooling and to prevent sweating, that is, con densation of the vapor expelled from the hot loaf in striking cold solid surfaces. While cooling, or when cooled, the bread in most modern shops is wrapped in paraffin paper for the double purpose of avoiding direct touch of the hands, and of keeping the bread fresh, as changed values are given to materials and processes; as new methods or processes are in troduced, or new requirements are made on the baker to meet government or food admin istration regulations.
The structure is usually of brick—two stories and a basement, with large windows, so that the process of bread making can be seen from the outside. Spacious offices, shipping rooms, retail sales room, wrapping rooms — the bread is never touched by hands except those of the white-gloved packers where automatic wrap ping machines are not yet used,— separate sani tary lavatories for all departments, mixer rooms, dough cutting, weighing and molding ma chinery rooms, proofing and oven rooms, boiler and oven-firing rooms, are all well ventilated and lighted so that there is no dark corner in the entire plant. All interior walls are kept white with enamel or granite paint, also the white framework of all machinery used, includ the impervious paper prevents the moisture of the bread from escaping.
All rye bread, excepting as pumpernickel, which is whole rye flour bread, is now made with bolted rye flour from which the bran and germ have been largely removed, is mixed with 25-35 per cent of wheat flour, water, salt, leaven, sugar, lard or other shortening; the dough is left to ferment in the trough; it is punched and the manufacture proceeds as with wheat bread.
A mixed rye bread, that is, bread from rye flour with an admixture of from 35 to 50 per cent of wheat flour, is prepared with yeast like wheat bread.
Bakery Construction and Equipment.— Space does not permit to go into the details of the various types of machines and apparatus, .ovens, proofers, troughs and other accessories of a modern bakery. Changes in construction and equipment have become necessary from time to time as baking technology progresses; as ing the proofing cabinets, while the brick or metal face of the ovens is white glazed or glass enameled. Everything is done with a view to add attractiveness to the place, so as to educate the visitor to give preference to the modern bakery output, as everything suggests sanitation and wholesomeness.
The mixing room is generally on the second floor, adjoining the flour warehouse, in which a considerable quantity of flour is always kept on hand to ensure proper ageing, since new flour will not give as good a loaf. The flour hopper or mixer feeder, with a capacity of five barrels of flour or more which is to feed the mixer, is portable, and may be conveyed to the various bin cone sifters from which the supply is taken. The hopper is run to one of the mixers, emptying its contents into it, and re turning to the same or another bin for another charge of flour. Into the mixer are carefully weighed the flour; the water; the shortening (lard or vegetable oil) ; salt; yeast, dissolved in water; sugar, usually in the form of cane sugar; malt extract. Metal dough troughs on wheels receive the mixed dough which is given time to ferment (usually 5 to sy, hours), the dough being kneaded or punched in the trough three times (see above). Then the troughs are wheeled to a chute in the floor and let down to the dividing machine, which is so arranged that it can cut any loaf from about 10 to 40 ounces. The dough is carried to the rounder auto matically, and from thence to the proofer, where it rests for about 10 minutes In a temperature of about 80°. The pieces of dough are now let down by a conveyor to the molding machine where they are molded into the form of loaves which are placed in the bread pans. These are loaded upon conveyor racks and wheeled into the proof cabinets, where they remain from 20 to 40 minutes, according to the individual notion of the baker, in an atmosphere of steam, at about The conveying racks are rolled from the proofer to the oven, which, according to capacity, receive a charge of 100 to 500 loaves of bread, the average baking period be ing 35 minutes, after which the loaves are taken out by a long, wooden pole, formed at the end like an oar blade, on which the pans are caught, an implement called a peel, or the pans are passed automatically to the front in those types of ovens called rotary ovens. The loaves are again loaded on the wheeled racks, are dumped on tables and after cooling are packed into cartons or paraffin paper and reach the delivery truck-wagon to be shipped to the different stores.