Use of Sulphate of Copper^ 8fc. in Bread. 275 



PART SECOND. 



Series of experiments on bread maki?ig. 



Considering the nature of the various materials resorted to for the 

 purpose of disguising the quality of bad flour, it is difficult to con- 

 ceive precisely in what manner they produce their effects. 



The desire of proving experimentally the influence of sulphate of 

 copper upon the progress of fermentation, induced the author to un~ 

 dertake a series of practical operations, upon the effects of this and 

 various other salts. These results are given in the order in which 

 they were obtained. The experiments were all made by the same 

 baker in the author's presence. 



First baking. 



Several kinds of flour were tried. 



1. Flour of 1829, — -slack, (Idchante,) — giving a dough which 

 spread out, without rising, so as to furnish only a heavy bread. 



2. Flour CB.\\ed pa iyi d^av 6 1 from wheat called JZawze, :| of the 

 bran only extracted. 



3. Flour of brown bread ; ten per cent, of bran extracted. 



With each of these, equal portions of yeast and leaven were in- 

 corporated and made equally moist. Different quantities of sulphate 

 of copper in solution were added, and mixed with the dough of dif- 

 ferent loaves, and kept in a warm place until fit for the oven. 



It was observed that the loaves destitute of the sulphate, merely 

 flattened out (pousser plat,) without increasing in height, while those 

 which contairied the smallest quantity swelled more and more, and 

 broke upon the surface, and the greater number became very porous. 

 Those however which had received the greatest proportion of cop- 

 per, did not sensibly increase in volume, and remained flat. They 

 were all baked together, remaining in the oven about half an hour. 

 The results are exhibited in the table. 



Observations on the first baking. 



Bakers are generally of opinion, that there are two distinct actions 

 in the rising of bread, the one owing to the leaven, which consists in 

 strengthening the paste, the other to the yeast and leaven together, 

 in the development of gas and increase of volume. 



