45. PURPOSE OF RISING.--Rising is an important part of the process of bread making, no matter which method is employed. In a sponge, its purpose is to blend the ingredients after they have been mixed, as well as to permit the growth of the yeast; in a dough, after the gas has been evenly distributed by means of kneading, the purpose of rising is to permit the incorporation of a sufficient quantity of carbon dioxide to make the bread light when it is baked. As has just been explained, three risings are necessary in the sponge method of both the long and the short process, whereas only two are required in the straight-dough methods. The last rising, or the one that takes place after the dough is shaped into loaves, is the one that affects the texture of the bread most, so that it should receive considerable attention. If the dough is not allowed to rise sufficiently at this time, the bread will be too fine in texture and will likely be heavy; and if it is permitted to rise too much, it will be coarse in texture. Allowance, however, should be made for the fact that the rising will continue after the bread has been placed in the oven.
46. TEMPERATURE FOR RISING.--As has been mentioned, the best results are obtained if the bread dough is kept at a uniform temperature throughout its rising. The temperature at which it rises most rapidly is about 86 degrees Fahrenheit; but, unless it can be watched closely, a better plan is to keep it, especially if the long process of bread making is followed, at a temperature that runs no higher than 80 degrees. Various methods of maintaining a uniform temperature have been devised, but the ones usually resorted to consist in placing the bowl containing the sponge or the dough in a bread raiser, a fireless cooker, or a vessel of hot water.
47. Bread raisers can be purchased, but if desired a simple bread-raising device may be constructed from a good-sized wooden box. To make such a device, line the box with tin or similar metal and fit it with a door or a cover that may be closed tight. Make a hole in one side of the box into which to insert a thermometer, and, at about the center of the box, place a shelf on which to set the bowl or pan containing the sponge or dough. For heating the interior, use may be made of a single gas burner, an oil lamp, or any other small heating device. This should be placed in the bottom of the box, under the shelf, and over it should be placed a pan of water to keep the air in the box moist, moist air being essential to good results. Where large quantities of bread must be baked regularly, such a device will prove very satisfactory. The temperature inside should be kept somewhere in the neighborhood of 95 to 105 degrees Fahrenheit if the bread is to rise rapidly; but it may be kept from 80 to 95 degrees if slower rising is desired.
48. Placing the bowl containing the dough mixture in a larger vessel of hot water is a simple and satisfactory way of obtaining a uniform temperature, being especially desirable for a sponge in the quick-process sponge method. The water in the large vessel should be at a temperature of about 110 to 115 degrees Fahrenheit. After the bowl of sponge or dough is placed in the water, the large vessel should be covered very carefully, so that the heat from the water will be retained. To maintain the temperature in the vessel and thus keep it right for the bread mixture, the hot water has to be replenished occasionally. If this is done, the sponge or dough will be maintained at a temperature of about 90 degrees and will therefore rise rapidly.
49. To insure the best results with the rising of bread mixtures, it is advisable, for the beginner at least, to use a thermometer for determining the temperature of air or water, as this instrument will save considerable time until experience in judging such matters has been gained. A Fahrenheit thermometer like that shown in Fig. 4 is the ideal kind for use in bread making. As an aid in this process, there are indicated in this illustration the temperature at which dough should be kept for rising and the temperature at which water should be kept outside the bowl to maintain a temperature of 75 to 90 degrees in the dough when the plan mentioned in Art. 48 for keeping dough at a uniform temperature is followed. In addition, the oven temperatures for baking bread and rolls, which are explained later, are also shown. The temperature of water can, however, be determined fairly accurately with the hands. If it feels very warm but does not burn the hand, it may be considered at about a temperature of 110 to 115 degrees.
In order to prevent the formation of a hard surface on the dough, the bowl in which it rises should be kept tightly covered. A further means of preventing this condition consists in oiling the surface of the dough; that is, brushing it lightly with melted fat. In case a crust does form, it should be well moistened with water or milk and allowed to soften completely before the next kneading is begun.
50. TIME REQUIRED FOR RISING.--No definite rule can be given for the length of time required for dough to rise, for this depends entirely on the activity of the yeast. If the yeast is active, the dough will rise quickly; but if it is not of good quality or if it has been killed or retarded in its growth by improper handling, the dough will rise slowly. Usually, dough should be allowed to rise until it has doubled in bulk. A good way in which to determine when this takes place is to put a small piece of the dough in a glass, such as a measuring glass, a tumbler, or a jelly glass, and mark on this glass where the dough should come when it has increased to twice its size. This glass set beside the vessel containing the dough will show when it has risen sufficiently. This plan is illustrated in Figures 5 and 6. Figure 5 shows a glass half filled with dough and a bowl of bread dough ready to be placed where they will keep warm for the first rising; and Figure 6 shows the same dough after it has doubled in bulk, as is evident from the fact that the glass is entirely full.