20 The Composition and Food ]*ali(e of Bread. 



worth to him sonu thing like Is. M. more per sack. From the 

 point of view of the food value of the liread produced it 

 appears at first sight that such a flour would produce a bread 

 containing an excessive amount of water, and a corres- 

 pondingly low percentage of dry matter. This is, however, 

 by no means the case, for the flours which absorb large amounts 

 of water are, as a general rule, flours which contain low per- 

 centages of;: natural moisture. Thus a flour containing only 

 10 per cent, of natural moisture, and absorbing in the doughing 

 process 103 quarts of water per sack, would produce bread 

 containing almost exactly the same percentage of water as a 

 flour which contained 1.") per cent of natural moisture and 

 absorbed only 92 quarts of water per sack. As a general rule 

 some such balance holds between natural moisture and water 

 absorption, but in exceptional cases flour high in natural 

 moisture may a]:>8orb much water, and the bread produced 

 from such flours no doubt contains an abnormally low 

 percentage of dry matter. The almost universal practice of 

 blending wheats in the mill must however reduce such cases 

 to a minimum, and their occurrence must be so unusual that 

 they can have little bearing on the general question of the 

 food value of bread. From a large number of analyses of 

 ])rea(-l, published in the Bulletins of the U.S. Department of 

 Agriculture, it appears that fresh bread contains on the average 

 36 per cent of water, and that the variation from this figure is 

 not often more than 2 per cent. 



The stability of a flour can have but little influence on the 

 food value of the bread produced from it. It is difficult to 

 see how the stickiness or otherwise of the dough can affect 

 the composition of the bread. This property of flour may 

 therefore be left without further discussion, and we may 

 proceed at once to discuss the question of strength proper. 



Strength has already been defined as the capacity of making 

 a large well piled loaf. It is clear at once that this definition 

 embodies two ideas. The loaf may be large or small, or it 

 may be well or badly piled, and there is no necessary con- 

 nection between these two properties. After many years of 

 careful investigation I am satisfied that the size of the loaf 

 produced by any flour depends on the diastatic capacity of the 

 flour, or, in non-technical language, on the presence in the 

 flour of a ferment which is able to change the starch of the 

 flour into sugar when provided with moisture and warmth 

 as it is in the dough. Such production of sugar provides food 

 for the yeast, which continues to grow and make gas inside 

 the dough up to the moment when the moulded loaf is put 

 into the oven. The more rapid the formation of gas inside 

 the dough, the greater the pressure in the loaf when it goes 



