Oil the Tlicory and Practice of Cookery 



SOI 



the fine quality of bread which is procurable 

 from them ; the richer varieties of hard glu- 

 tinous Avheat being used only to impart 

 strength to weak and inferior descriptions of 

 flour. 



BREAD YEAST, ITS PROPERTIES, USES, AND 



SUBSTITUTES. 



Breads which is the most important pre- 

 paration of flour, owes its value as an article 

 of diet to a good and equable vesiculation of 

 the dough, the vesiculation being effected by 

 the diffusion of small bubbles of carbonic 

 acid gas tiiroughout its substance ; and, as 

 this vesiculation can only take place in a 

 proper manner when the gluten of the flour is 

 in sufliicient quantity, and of good quality, it 

 is, to some extent, a test of the goodness of 

 the meal. Those flours which contain too 

 little gluten, or gluten which is deficient of 

 strength, cannot be vesiculated into bread. 

 This is the case with almost every description 

 of flour, excepting that of wheat and rye. 



The most common, and also the most 

 antient method of vesiculating bread is by 

 fermentation ; and the process is not very 

 diff"erent from what it was in very early times, 

 Avhen we were told that " a little leaven leav- 

 eneth the whole lump." Yeast of some sort — 

 as brewers' yeast ; or patent yeast, prepared 

 from infusion of malt and hops ; or German 

 yeast, which is the solid residue of the yeast 

 produced by the fermentation of rye for 

 making Hollands ; or bakers' yeast, which is 

 made from potatoes and flour; or leaven, 

 which is old dough in a state of fennentation, 

 is mixed with the flour or dough, which soon 

 begins to ferment by the action of the yeast 

 fungus (micoderma cere\isiae) on the sugar of 

 the flour. Carbonic acid is thus produced ; 

 and by being diffused through the substance 

 of the dough it vesiculates it, and causes it to 

 rise or swell. The most usual practice with 

 the baker is somewhat as follows : — A special 

 ferment is prepared from mealy potatoes 

 (technically called fruit) by boiling them in 

 water, mashing them, and allowing them to 

 cool to a temperature of about 80^ of Fahren- 

 heit. Yeast is then added to them, together 

 with a little flour to hasten the fermentation. 



In three or four hours, at a proper tempera- 

 ture (as from 80^ to 90° Fah.), the whole 

 mass is generally in a state of active fermen- 

 tation, with a sort of cauliflower-head. It is 

 then diluted with water and strained, and is 

 mixed with sufficient flour to make a rather 

 thin dough, which in about five hours rises tO' 

 a fine sponge. This is again diluted with, 

 water containing salt, and is worked with the 

 necessary quantity of flour into dough, and 

 allowed to stand for two or three hours, when 

 it rises, and is in a fit condition to be baked, 

 into loaves. 



It can hardly be said that the potatoes are- 

 an adulteration in this case, for they do not 

 ever amount to more than- 6 lb. to a sack 

 of flour, which makes about 380 lb. of bread,, 

 or 94 4-lb. loaves. The salt is added to the 

 extent of about 4 lb. or more to a sack of" 

 flour, the proportions being regulated accord- 

 ing to circumstances, for the object of it is. 

 to improve the quality of the loaf as regards, 

 whiteness, firmness, and flavour. 



There is, no doubt, a slight loss of nutri- 

 tive matters by this mode of vesiculation, for 

 a small portion of the sugar of the flour is 

 converted into alcohol and carbonic acid, 

 but the quantity is so inconsiderable as to be 

 undeserving of notice. The advantage of the 

 process, however, is that it is an excellent 

 test of the quality of the flour; for weak 

 flour, or flour that has been injured by ger- 

 mination, or by keeping, will not stand the 

 action of yeast, but will be either ropy, or 

 sticky, or heavy, when baked into bread. 



Another method of vesiculation is to gene- 

 rate carbonic acid in the dough by the action 

 of an acid on bicarbonate of soda. Dr Whit- 

 ing's process, which was patented in 1836, 

 was to mix the carbonate of soda with the 

 flour, and then to act on it with a proper 

 proportion of muriatic acid added to the 

 water. He used from 350 to 500 grains of 

 carbonate of soda to 7 lb. of flour, and to 

 this he added 2% pints of water charged with 

 from 420 to 560 grains of muriatic acid. 

 Other proportions are used by bakers who 

 make unfermented bread ; but in all cases the 

 proportions should be such as to form com- 

 mon salt (which is the pi'oduct of the action 



