BREAD 479 



and heaving up is due to carbonic acid, generated by tko fermentation induced in the 

 mass, -which may be thus left until -wanted. In about three hours, this fermenting 

 action -will appear to bo at an end, and when it has arrived at that stage, it is fit 

 to bo used. The ferment, however, may bo left for six or seven hours and be still 

 very good at the end of that time, but the common practice is to use it within four or 

 five hours after its preparation. After this the ferment rapidly becomes sour. 



The next operation consists in ' setting the sponge' This consists in stirring the 

 ferment well, adding thereto about two gallons of lukewarm water, and as much flour 

 as will make, with the ferment, a rather stiff dough. This constitutes ' the sponge. 1 

 It is kept in a warm situation, and in the course of about an hour fermentation again 

 begins to make its appearance, the mass becomes distended or is heaved up by the 

 carbonic acid produced, the escape of which is impeded by the toughness of the mass. 

 This carbonic acid is the result of the fermentation induced under the influence of 

 water, by the action of the gluten upon the starch, a portion of which is converted 

 thereby into sugar, and then into alcohol. A time, however, soon comes when tho 

 quantity of carbonic acid thus pent up becomes so great that it bursts through, and tho 

 sponge collapses or drops down. This is called the first sponge. But as the fermen- 

 tation is still going on, the carbonic acid soon causes the sponge to rise again as before 

 to nearly twice its volume, when tho carbonic acid, bursting through the mass, causes 

 it to fall a second time ; and this constitutes what the bakers call the second sponge. The 

 rising and falling might then go on for twenty-four hours ; but as the alcoholic would 

 pass into the acetous fermentation soon after the second rising, the baker always inter- 

 feres after the second, and very frequently after the first sponge. The bread made from 

 the first sponge is generally sweeter ; but unless the best flour is used, and oven then, 

 the loaf that is made from it is smaller in size and more compact than that which is made 

 with the second sponge. In hot weather, however, as there would bo much danger of 

 the bread turning sour, if tho sponge were allowed to ' take a second fall,' the first 

 sponge is frequently used. The next process consists in ' breaking the sponge,' which is 

 done by adding to it tho necessary quantity of water and of salt, the quantity of the 

 latter substance varying from Ib. to f of a pound per bushel of flour ; that is, from 

 2 Ibs. to 3| Ibs. per sack of flour (new flour, or flour of inferior quality, always 

 requires, at the very least, 3i Ibs. per sack, to bind it, that is to say, to render the 

 dough sufficiently firm to support itself while fermenting.) Salt acts, to a groat 

 extent, like alum, though not so powerfully. As to the quantity of water to be used, 

 it depends also a great deal on the quality of tho flour, the best quality absorbing 

 most ; though, as we shall have occasion to remark, the baker too often contrives to 

 force and keep into bread made from inferior flour, by a process called under baking, 

 tho same amount of water as is normally taken up by that of the best quality. Gone- 

 rally speaking, and with flour of good average quality, the amount of water is such, 

 that the diluted sponge forms about 14 gallons of liquid. Tho whole mass is then 

 torn to pieces by the hand, so as to break any lumps that thero may be, and mix it 

 up thoroughly with tho water. This being done, the rest of the sack of flour is 

 gradually added and kneaded into a dough of the proper consistency. This knead- 

 ing of the dough may bo said to be one of the most important processes of tho 

 manufacture, since it not only produces a more complete hydration of the flour, but, 

 by imprisoning a certain quantity of air within tho dough, and forcibly bringing into 

 closer contact tho molecules of the yeast or leaven with the sugar of the flour, and 

 also with a portion of the starch, the fermentation or rising of the whole mass, on 

 which tho sponginess of the loaf and its digestibility subsequently depend, is secured. 

 When by forcing the hand into the dough, the baker sees that, on withdrawing it, 

 none of tho dough adheres to it, he knows that the kneading is completed. The dough 

 is then allowed to remain in the trough for about an hour and a half or two hours, 

 if either brewers' or German yeast have been employed in making the sponge ; if, on 

 the contrary, patent yeast or hop yeast have been used, three or even four hours may be 

 required for the dough to rise up, or, as in technical language, to give proof. When tho 

 dough is sufficiently 'proofed,' it is weighed of into lumps, shaped into the proper 

 forms of 4 Ibs. 4 oz. each, and exposed for about one hour in an oven to a tempe- 

 rature of about 570 F., the heat gradually falling to 430 or 420 F. The yield after 

 baking is 94 quartern (not 4-lb.) loaves, or from 90 to 92 really 41b. loaves, as largo 

 again as they wore when put into the oven in the shape of dough. 



The manner in which yeast acts upon tho flour is, as yet, an unsolved mystery, 

 or at any rate an, as yet, unsatisfactorily explained action ; for tho term ' catalysis,' 

 which has sometimes been applied to it, explains absolutely nothing. 



A yeast, or fermenting material, may be prepared in various ways ; but only throe 

 kinds of yeast are used by bakers : namely, brewers' yeast, or barm, German yeast, 

 and patent, or hop yeast. 



The most active of these ferments is the first, or brewers' yeast ; it is, as is well 



