MIXTURES WITH BREAD. 45 



The want of gluten in some grains and roots prevents the rising of 

 the bread made of them. All the alcohol produced by the vinous fer- 

 mentation of dough is evolved in the process and in baking. The 

 carbonic acid not being volatile, is likely to prove injurious to bread, 

 especially if the flour should not be fresh or of a good quality. To 

 correct this, sub carbonate of ammonia, or carbonate of magnesia, may 

 be added, which both prevents the acidity and improves the quality of 

 bread. Thus, Sir H. Davy says, loaves are made by it to rise well in 

 the oven, and when baked are light and spongy, have a good taste, 

 and keep well. The carbonate of ammonia is entirely dissipated in 

 baking ; it neutralizes any acid in the dough and makes biscuit short. 



20 to 30 grains of carbonate of magnesia to the pound of new and 

 poor flour much improves bread ; and when the flour is of the worst 

 quality, 40 grains are required to produce a like effect. Alum is also 

 much used by bakers, in the proportion of 2 oz. to 5 bushels of flour. 

 A distinguished chemist says that it is impossible to produce white, light 

 and porous bread in London without the use of alum, unless ihe flour 

 is of a very fine quality. It is believed that no such declaration is ne- 

 cessary in this country, yet we have reason to believe that much poor 

 flour is used by our bakers, and that alum is much resorted to to im- 

 prove the appearance of their bread. A simple method of delecting 

 this is to mix crumbs of the stale bread in water, squeeze the paste 

 through a cloth, then pass the liquor through a filter-paper and the re- 

 sulting limpid infusion, if it contain alurn, will exhibit a white cloud 

 on adding to it a dilute solution of muriate of barytes. These salts 

 are said to have little effect on the rising of bread, and the former is 

 converted into an acetate by combining with the free acid in the dough. 

 The use of common salt is thought to be slightly like that of alum or 

 blue vitriol. 



The effect of such bread is evidently injurious, especially on those 

 who are costive, with impaired digestion. Both white and blue vitriol 

 are also used by bakers ; much more in parts of Europe, we trust how- 

 ever, than in this country, for there can be no reasonable apology for 

 the use of any deleterious substances in the bread of our people ; no- 

 thing but reckless cupidity can induce the practice. In Belgium and 

 France this is most common. The ostensible effect of the latter on 

 bread is like yeast, to retain the gas and render the bread more porous. 

 A minute quantity produces this effect, even a grain in 1\ Ibs. of 

 bread. Double this is said to produce a greater rising, but still more 

 renders the bread flat and moist. 



Bread is sometimes adulterated with carbonates of soda and potassa, 

 to prevent it from becoming soon dry. Plaster of Paris, chalk, whit- 

 ing and burnt bones are also used. 



Potato flour is a common addition to wheat flour in bread making 

 in Europe, but this can hardly be called an adulteration, if the price is 



