The Story of a Loaf of Bread

by T. B. Wood

Fig. 16. Apparatus arranged for a baking test. Four loaves which have just been scaled and moulded are seen in an incubator where they are left to rise or prove before being transferred to the oven

Fig. 17. The loaves shown in the last figure have just been baked and are ready to be taken out of the oven, the door of which is open. Note the different shapes. That on the right hand is obviously shown by the test to be made from a strong flour, the other from a very weak flour

The process of kneading causes the particles of gluten to absorb water and to adhere to one another, so that the dough may be regarded as being composed of innumerable bubbles each surrounded by a thin film of gluten, in or between which lie the starch grains and other constituents of the flour. Each yeast cell as above explained forms a centre for the formation of carbon dioxide gas, which cannot escape at once into the air, and must therefore form a little bubble of gas inside the particular film of gluten which happens to surround it. The expansion of the dough is due to the formation inside it of thousands of these small bubbles. It is to the formation of these bubbles too that the porous honey-combed structure of wheaten bread is due. Also since the formation of the bubbles is due to the retention of the carbon dioxide by the gluten films, such a porous structure is impossible in bread made from the flour of grains which do not contain gluten.

The rising of the dough is usually allowed to proceed for several hours. The baker finds by experience how long a fermentation is required to give the best results with the flours he commonly uses. When the proper time has elapsed, the dough is removed from the trough or pan in which it was mixed to a board or table, previously dusted with dry flour to prevent the dough adhering to the board or to the hands. It is then divided into portions of the proper weight to make loaves of the desired size. This process is known technically as scaling. Usually 2 lbs. 3 ozs. of dough is allowed for baking a 2 lb. loaf. Each piece of dough is now moulded into the proper shape if it is desired to bake what is known as a cottage loaf, or placed in a baking tin if the baker is satisfied with a tinned loaf. In either case the dough is once more kept for some time at a sufficiently warm temperature for the yeast to grow so that the dough may once more be filled with bubbles of carbon dioxide gas. As soon as this second rising or proving has proceeded far enough the loaves are transferred to the oven. Here the intense heat causes the bubbles of gas inside the dough to expand so that a sudden increase in the size of the loaf takes place. At the same time the outside of the loaf is hardened and converted into crust.

After remaining in the oven for the requisite time the bread is withdrawn and allowed to cool as quickly as possible, after which it is ready for use or sale.

The method of baking which has been described above is known as the off-hand or straight dough method. It possesses the merit of rapidity and simplicity, but it is said by experts that it does not yield the best quality of bread from certain flours. Perhaps the commonest variation is that known as the sponge and dough method, which is carried out as follows. As before, the requisite amount of flour is weighed out into the mixing trough, and a depression made in it for the reception of the water and yeast. These are mixed together in the proper proportions, enough being taken to make a thick cream with about one quarter of the flour. This mixture is now poured into the depression in the flour, and enough of the surrounding flour stirred into it to make a thick cream or sponge as it is called. At the same time a small quantity of salt is added to the mixture. The sponge is allowed to ferment for some hours, being kept warm as in the former method. As soon as the time allowed for the fermentation of the sponge has elapsed, more water is added, so that the whole or nearly the whole of the flour can be worked up into dough. This dough is immediately scaled and moulded into loaves, which after being allowed to prove or rise for some time are baked as before. This method is used for flours which do not yield good bread when they are submitted to long fermentation. In such cases the mellow flours, which will only stand a very short fermentation, are first weighed out into the mixing trough, and a depression made in the mass of flour into which a quantity of strong flour which can be fermented safely for a long time is added. It is this last addition which is mixed up into the sponge to undergo the long preliminary fermentation. The rest of the flour is mixed in after this first fermentation is over, so that it is only subjected to the comparatively slight fermentation which goes on in the final process of proving.

Many other modifications are commonly practised locally, their object being for the most part to yield bread which suits the local taste. It will suffice to mention one which has a special interest. In this method the essentially interesting point is the preparation of what is known as a ferment. For this purpose a quantity of potatoes is taken, about a stone to the sack of flour. After peeling and cleaning they are boiled and mashed up with water into a cream. To this a small quantity of yeast is added and the mixture kept warm until fermentation ceases, as shown by the cessation of the production of gas. During this fermentation the yeast increases enormously, so that a very small quantity of yeast suffices to make enough ferment for a sack of flour. The flour is now measured out into the trough, and the ferment and some additional water and salt added so that the whole can be worked up into dough. Scaling, moulding, and baking are then conducted as before. This method was in general use years ago when yeast was dear. It has fallen somewhat into disuse in these days of cheap compressed yeast, in fact the use of potatoes nowadays would make the process expensive.

In private houses and in the smaller local bakeries the whole of the processes described above are carried out by hand. During the last few decades many very large companies have been formed to take up the production of bread on the large scale. This has caused almost a revolution of the methods of manipulating flour and dough, and in many cases nowadays almost every process in the bakery is carried out by machinery. In many of the larger bakeries doughing and kneading are carried out by machines, and this applies also to the processes of scaling and moulding. A similar change has taken place too in the construction of ovens. Years ago an oven consisted of a cavity in a large block of masonry. Wood was burned in the cavity until the walls attained a sufficiently high temperature. The remains of the fuel were then raked out and the bread put in and baked by radiation from the hot walls.

Nowadays it is not customary to burn fuel in the oven itself, nor is the fuel always wood or even coal. The fuel is burned in a furnace underneath the oven, and coal or gas is generally used. Sometimes however the source of heat is electricity. In all cases it is still recognised that the heat should be radiated from massive solid walls maintained at a high temperature. In the latest type of oven the heat is conducted through the walls by closed iron tubes containing water, which of course at the high temperatures employed becomes superheated steam. It is recognised that the ovens commonly provided in modern private houses, whether heated by the fire of the kitchen range, or by gas, are not capable of baking bread of the best quality, because their walls do not radiate heat to the same degree as the massive walls of a proper bake oven.