Experimental cookery

bread dough the increased acidity is largely due to carbon dioxide. The />H of the baked bread is always higher than that of the dough from which it is baked. For an average gluten a ^H of about 5 is desirable. With all doughs, if the fermentation is carried too far the volume of the bread is poor and it has a sour odor and flavor. The following table is from Bailey and Sherwood. TABLE 52 Hydrogen-ion Concentration (in Terms of ^H) and Titratable Acidity OF Bread Dough Suspensions {Bailey and Sherwood) pW Dough No. 1 titratable acidity pn Dough No. 2 titratable acidity 1. Fresh dough 2. Fresh dough after 5 hours 3. Baked bread 5.76 5.24 5.43 1.10 3.36 5.75 5.18 5.38 1.10 3.50 Length of fermentation period. The total length of the fermenta- tion period depends upon the proportion of yeast used and the temperature at which the sponge or dough is kept. The first rising should double in bulk and should spring back easily when pressed with the finger. It is usually given the longest period and often requires 70 per cent of the total fermentation time. The dough is then punched and worked lightly to 434 FLOUR AND BREAD allow the gas to escape. The second rising requires a shorter time than the first one, and the dough may be punched and molded and placed in the pans. Very strong glutens may be allowed to rise a third time before putting in the pan. Dunlap has reported that, with a high initial hydrogen-ion concentra- tion, or induced acidity, produced by the addition of acid or some substance that increases the acidity, better bread is secured if the fermentation periods are reversed, that is the first rising period is short, and the second longer. If the dough is baked before fermentation has progressed far enough, the resulting bread has thick cell walls and is decidedly less tender than bread fermented sufficiently. The volume is also smaller. This is because the gluten with the proper length of fermentation becomes more dispersed and tender. If fermentation is carried too far the gluten becomes too soft to retain all the expanding gas bubbles and several cells coalesce, which produces thick cell walls and coarse texture. With extreme fermentation the dough smells sour, and a very coarse, heavy, compact bread of small volume and sour taste is obtained. Prevention of crust forination during fermentation. Drying of the crust may be partially or wholly prevented by covering, keeping in a cabinet with high humidity, or greasing the crust. A crust formed after the dough is panned gives a dry layer on top that is less elastic. Often a layer of compact grained cells is formed just below the crust because of the drying of the crust, and as a result it is inelastic. The drying in the pan may be prevented in the same way as during rising, or the crust may be moistened with water occasionally. Size of pan. The volume of the loaf and the shape of cells of the bread depend upon the method of panning and the relation of the amount of dough to the size of the pan.