RELATIVE COST OF CORN, FLOUR, AND BREAD. 607 



Cost of Flour, Cost of Bread, Market price of 



per sack. per stone. per quartern loaf. Grain per qr. 



45s. 2s. 3d. 5|d. 60s. 



50s. 2s. 6d. 6d. 67s. 



55s. 2s. 9d. 6^d. • 72s. 



60s. 3s. Od. 7|d. 80s. 



The economy of baking at home, therefore, at the usual prices of 

 bread, seems to be very considerable. 



§ 12. Of the supposed relation between the per-centage of gluten in 

 flour, and the weight of bread obtained from it. 



It has been assumed by recent chemical writers that the quantity of 

 water absorbed by flour, and consequently the weight of bread obtained 

 from it, depends, in whole or in great part, upon the proportion of gluten 

 which the flour contains. The following facts, however, do not accord 

 with this supposition. 



1°. Household bread, made respectively from the flour of a French 

 wheat and of a wlieat from Taganrog, retained nearly the same per- 

 centage of water, though the one sample contained upwards of twice as 

 much gluten as the other. Thus — 



Gluten per cent. Water per cent, 



in the Flour. in tiie Bread. 



Flour of Brie . . . 10-7 47-4 



Flour of Taganrog . . 22-7 47-0 



This one fact might be supposed to settle the question, but I shall 

 mention others. 



2°. The flour from Odessa wheat contains about ^th more gluten than 

 French flour in general, and j^et it absorbs very little more water (Du- 

 mas). This Dumas accounts for by the fact that the starch of the 

 Odessa wheat forms hard transparent horny particles, which take less 

 water to moisten them than the impalpable powder yielded by the softer 

 French wheats — so that tlie gluten does not appear to produce its full 

 effect. I do not know how far this explanation is consistent with the 

 fact that the hard flinty wheats give the best biscuit flour — what the 

 baker calls the strongest, which rises best, and absorbs the most water.* 



3°. Rice is said to contain very little gluten — not estimated by any to 

 amount to more than 6 or 7 per cent. — and yet it is stated as the result of 

 numerous trials, that an admixture of a seventh part of rice flour causes 

 wheaten flour to absorb more water. f 



4°. If the hard wheats be ground too fine they lose a part of their ap- 

 parent strength, the flour becomes dead, as it is sometimes called, and 

 refuses to rise as it would do if sent to the baker in a more gritty and less 

 impalpable state. 



6°. Lastly, the admixture of very minute quantities of foreign matter, 

 by way of adulteralioa, is said to have a remarkable influence upon the 

 quantity of water which the flour will absorb. In some parts of Belgium 

 it appears to have been the practice to adulterate the bread with a small 

 quantity of sulphate of copper.J This salt is dissolved in water, and 



• That such Is the case also in foreign countries, see a letter from the British Consul at 

 Lisbon, in Davy's Agricultural Chemistry, Lecture IIL 

 t Dumas' Traite de Chimie, vi., p. 396. 

 t Blue vitriol— e v'olent poison. 



