The Sweetness Of Fermented Bread

The littlc cavit.i s in a loaf of bread, whieh give it lts spougy charaoter, and uiakö it liglit, aro fonncd by the expansión of littlo bubbles of carbonic acid gas; aud there are three different uiethods by which these little uia.sses of carbouic acid ire inipgled with tb e dough. Iu makiug what is c;illed arerated bread, the carbouie acid is obtuiuud by an economical procoss, and is tben meohanically mixed witb the dough by agitatiög the two togctlior ip au utrtigut vessel. On boing placed in a hot oven the bubbles of g'is expuud, and puff the dough iuto a spoiigy ma.-s. Suda bicuit are ruised by setting free carbonic: acid from bicarbonate of aoda. This aalt is componed of soda, carbouie acid, and water, and if it be brought in contact with tartaric acid, the soda leaves the carbouie acid to combino vvith the tartaric, and the carbonic acid is set free in the fortuatinri of gas. Advantage is taken of these affinities to distribute carbouic acid gas in minute niasses through the dough. Tartaric acid ia thoroughly ineorporated with the dough, and tben bicarbonato of soda is added and also thoroughly mixed with the masa. The tartrnte of soda, formed by the combination of tartaric acid and soda, of course remaius in the dough, and is taken into the Btomaoh with the bread. Iu fermented bread tho carbonic acid is obtained from the flour. All grain contains starch, and by proper treatnient starch may be converted into grapesugar, which in its turn may be changed into carbonie acid and alcohol. Both of these changes are eöected by ferinentation. Pauic fermentation is simply tho grorttb of yeast. Yeast is a microscopio plant, aud when immersed iu a proper liquid and subjected to the proper porature, it propagates and grows with greát rupidity. When it grows iu contact with moisteuod starch it converts tho starch first iuto sugar, and then the sugar into carbomc acid and alcohol. - The sweetness oi formenled bread is doubüess due to the circumstance that a portion of the sugar formed from tho staroh remains in the bread without bo ing ehangüd iuto carbonio acid and alcohol. - Soientifio American.