AERATED BREAD. Ordinary bread is leavened by yeast, the vesicular texture being imparted by the consequent fermenta tion, which produces carbonic acid gas. Dr. Dauglish invented a process by which bread is directly charged with carbonic acid gas, and to bread so lightened the name "aerated" is given. Machinery for the purpose was first devised about 186o. In the aerating process, the carbonic acid gas is supplied to the flour in conjunction with the water, and the lightening is thus performed without any decomposition whatever. For this reason it is claimed that aerated bread will agree with persons who find they cannot digest ordinary bread through the fermenting process continuing after the bread is eaten.
The mixing of aerated bread is performed in a hollow air-tight receptacle by the revolution of iron arms fixed upon a central spin dle. Aerated water is pumped into the mixing receptacle at a very high pressure, and when the kneading is finished a valve is opened at the bottom of the mixer and the dough is forced out by the elasticity of its contained carbonic acid gas. As the dough issues from the machine it is cut off in portions of the required weight and goes forward in tins to the oven. The aerated process is much quicker than the ordinary method of bread-making with yeast, as with the former an hour and a half serves for the entire conversion of a sack of flour into baked loaves, whereas with the latter process four or five hours are occupied in the formation of the dough and a further period of approximately an hour and a half in the mould ing and baking.
Perry and Fitzgerald developed a process for mechanically in jecting carbon dioxide into a dough while it is being mixed, and claim a patent was issued on March 9, 1885. Their method differs from the Dauglish process in that the gas is injected directly into the mixer while the dough is being mixed. Bailey and Le Clerc, of the U.S. Department of Agriculture, published a method in which hydrogen peroxide is used as the aerating agent for leaven ing bread doughs and the like. Carbon dioxide in the compressed state known as "dry ice" has also been recommended as a means of aerating doughs for bread making purposes.