^ per cent, of albumenoids, 2.40 per cent, of which (23.6 per cent, of the whole) is soluble in water. In spring wheat the average is 12.41 per cent, of albumenoids, of which 3.74 (30.1 of the whole) is soluble in water. The albumenoids constitute the muscle-producing portions of the flour, the rest being chiefly starch, which produces fat and supplies heat to the living machine. The soluble portion of the gluten dissolves in the water used in mixing, and is thus distributed through the whole mass. When heated this albumen coagulates and encloses the starch cells which have burst from the effect of the heat, while the carbonic acid gas, which is imprisoned in the mass, preserves the porous or "light" character of the loaf, which, when eaten, is readily acted upon by the fluids of the stom- ach. The heavy loaf may contain the same nutriment as the light but its close mass is indigestible. If the heat is not sufiicient to, penetrate the entire mass, and produce the same conditions in the centre as near the surface, the loaf will collapse and be heavy in the centre. THE YEAST. If a mass of dough is allowed to remain in a warm place for some time, fermentation begins, and if dough in which this ferment- 4 BREAD-MAKING. H ing action has begun, is mixed with a larger mass of moistened flour, the fermenting process rapidly spreads through the whole and in a few hours it rises. The swelling of this mass being caused by the formation of bubbles by carbonic acid gas entangled in the dough. This process of fermentation is caused by a low order of vegetable growth called the yeast plant which presents some curious phases imder the microscope. It grows with marvellous rapidity, by a continuous budding of new cells upon those already formed. These cells of the yeast plant are so small as to be carried about in the air everywhere when the temperature is such as to maintain their vitality, and coming in contact with any substance like dough which afibrds them a good place for development, they rapidly in- crease in number until the entire mass becomes filled with them. Such a mass becomes the leaven used for ages in the preparation of bread. It is simply a convenient way of preserving and utilizing the yeast-plant. In the process of growth in the dough the yeast plant forms alcohol and carbonic acid in the sugar, and this is the reason why yeast is so generally used in the preparation of bread for the oven. Other methods of rendering the dough porous and light have also been adopted. Sour milk and saleratus have been in use for a century, the lactic acid of the sour milk setting free the carbonic acid in the saleratus. Bicarbonate of soda (cooking soda) has been mixed with the flour and a sufficient ^quantity of hydro- chloric acid added to the water used in moistening the flour to liberate the carbonic acid and form with the soda, common salt. Water charged with carbonic acid has also been used in mixing up the dough under pressure in iron cylinders, the carbonic acid expanding upon being liberated from the pressure and thus lightening the mass. The so- called aerated bread is thus prepared without the use of yeast or the loss by fermentation of any portion of the flour, as is of course the case when yeast is employed, but none of * these methods has ever become popular as a substitute for yeast in bread-making.

AI-modernized reading of the original text

^ per cent, of albumenoids, 2.40 per cent, of which (23.6 per cent, of the whole) is soluble in water. In spring wheat the average is 12.41 per cent, of albumenoids, of which 3.74 (30.1 of the whole) is soluble in water. The albumenoids constitute the muscle-producing portions of the flour, the rest being chiefly starch, which produces fat and supplies heat to the living machine. The soluble portion of the gluten dissolves in the water used in mixing, and is thus distributed through the whole mass. When heated this albumen coagulates and encloses the starch cells which have burst from the effect of the heat, while the carbonic acid gas, which is imprisoned in the mass, preserves the porous or "light" character of the loaf, which, when eaten, is readily acted upon by the fluids of the stomach. The heavy loaf may contain the same nutriment as the light but its close mass is indigestible. If the heat is not sufficient to penetratee the entire mass, and produce the same conditions in the centre as near the surface, the loaf will collapse and be heavy in the centre. THE YEAST. If a mass of dough is allowed to remain in a warm place for some time, fermentation begins, and if dough in which this ferment- ing action has begun, is mixed with a larger mass of moistened flour, the fermenting process rapidly spreads through the whole and in a few hours it rises. The swelling of this mass being caused by the formation of bubbles by carbonic acid gas entangled in the dough. This process of fermentation is caused by a low order of vegetable growth called the yeast plant which presents some curious phases under the microscope. It grows with marvellous rapidity, by a continuous budding of new cells upon those already formed. These cells of the yeast plant are so small as to be carried about in the air everywhere when the temperature is such as to maintain their vitality, and coming in contact with any substance like dough which affords them a good place for development, they rapidly increase in number until the entire mass becomes filled with them. Such a mass becomes the leaven used for ages in the preparation of bread. It is simply a convenient way of preserving and utilizing the yeast-plant. In the process of growth in the dough the yeast plant forms alcohol and carbonic acid in the sugar, and this is the reason why yeast is so generally used in the preparation of bread for the oven. Other methods of rendering the dough porous and light have also been adopted. Sour milk and saleratus have been in use for a century, the lactic acid of the sour milk setting free the carbonic acid in the saleratus. Bicarbonate of soda (cooking soda) has been mixed with the flour and a sufficient quantity of hydrochloric acid added to the water used in moistening the flour to liberate the carbonic acid and form with the soda, common salt. Water charged with carbonic acid has also been used in mixing up the dough under pressure in iron cylinders, the carbonic acid expanding upon being liberated from the pressure and thus lightening the mass. The socalled aerated bread is thus prepared without the use of yeast or the loss by fermentation of any portion of the flour, as is of course the case when yeast is employed, but none of * these methods has ever become popular as a substitute for yeast in bread-making.

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