THE CHEMISTRY OF COOKERY. 517 



pear as though they had been varnished, and their crust is partially- 

 soluble in water. 



This explains the apparent paradox that hard crust, or dry toast, 

 is more easily digested than the soft crumb of bread ; the cookery of 

 the crumb not having been carried beyond the mere hydration of the 

 gluten and the starch, and such degree of dextrin formation as was 

 due to the action of the diastase of the grain during the preliminary 

 period of " rising." 



Everybody has, of course, heard of " aerated bread," and most have 

 tasted it. Several methods have been devised, some patented, for ef- 

 fecting an evolution of gas in the dough without having recourse to 

 the fermentation above described. One of these is that of adding a 

 little hydrochloric acid to the water used in moistening the flour, and 

 mixing bicarbonate of soda in powder with the flour (to every four 

 pounds of flour one half ounce bicarbonate, and four and a half fluid 

 drachms of hydrochloric acid of 1 '16 specific gravity). These com- 

 bine and form sodium chloride, common salt, with evolution of car- 

 bonic acid. The salt thus formed takes the place of that usually 

 added in ordinary bread-making, and the carbonic-acid gas evolved 

 acts like that given off in fermentation ; but the rapidity of the action 

 of the acid and carbonate presents a difficulty. The bread must be 

 quickly made, as the action is soon completed. It does not go on 

 steadily increasing and stopping just at the right moment, as in the 

 case of fermentation. 



I remember the first introduction of this about half a century ago, 

 and the anticipations which accompanied it. London was agitated by 

 the bread-reform movement, and bakers were alarmed. A large estab- 

 lishment was opened in Oxford Street, and much amusement created 

 by an opposition placard display in some of the neighboring bakers' 

 shops, " Bread sold here with the gin in it." This, of course, was 

 fallacious^ as the alcohol produced by the panary fermentation is 

 driven off by the heat of the oven. Other methods similar in prin- 

 ciple have been adopted, such as adding ammonia carbonate with the 

 soda carbonate. The ammonia salt is volatile itself, besides evolving 

 carbonic acid by its union with the acid. 



In spite of the great amount of ingenuity expended upon the 

 manufacture of such unfermented bread and the efforts to bring it 

 into use, but little progress has been made. The general verdict ap- 

 pears to be that the unfermented bread is not so " sweet," that it 

 lacks some element of flavor, is "chippy" or tasteless as compared 

 with good old-fashioned wheaten bread, free from alum or other adul- 

 teration. My theory of this difference is that it is due to the absence 

 of those changes which take place while the sponge or dough is rising, 

 when, if I am right, the diastase of the grain is operating, as in ger- 

 mination, to produce a certain quantity of dextrin and sugar, and pos- 

 sibly acting also on the gluten. Deficiency of dextrin is, I think, the 



