80 Dr Colquhoun on the Art of' baking Bread. 



with the flour, or by the circumstance, that the carbonic acid gas, 

 disengaged by the uncombined acid contained originally in the 

 treacle, has thereby more leisure to penetrate into the system 

 of the dough, and to produce a more complete separation of its 

 particles. And it may be mentioned, as a circumstance in sup- 

 port of this explanation, that though the period of keeping re- 

 quisite in the preparation of gingerbread-dough is generally 

 from five to ten days, it is sometimes materially less, and that 

 without the manufacturer s being able to assign any cause for 

 the variation. But this, of course, might be readily accounted 

 for on the supposition, that treacle generally contains a variable 

 quantity of uncombined acid, and that this ingredient is the 

 true agent in developing carbonic acid gas within the dough, by 

 its action upon the alkaline carbonate, Upon the whole, there- 

 fore, it seems not improbable, that the mutual action of the 

 potashes and treacle, out of which results the gasifying of gin- 

 gerbread-dough, consists in the treacle containing a litle un- 

 combined acid, which, uniting with the potashes, sets carbonic 

 acid gas at liberty, and thereby renders gingerbread light and 

 elastic."" 



" In the course of performing these experiments, the details of 

 which have been subjoined in a note to p. 278, and the results 

 of which have led to the above conclusions, it was impossible 

 not to be impressed with a sense of the inconveniences that of- 

 ten arise to the baker from the delay occurring in the process, 

 and of the injury which may not unfrequently accrue to the con- 

 sumer, from the deleterious nature of one of the ingredients 

 which is essential in the present system. This is the carbonate 

 of potash, which it is always necessary to use in such a quantity 

 as gives a distinct disagreeable alkaline flavour to the bread, 

 whenever this is not disguised by mixture with some aromatic 

 ingredient. Nor can there be much doubt, that if gingerbread, 

 as now made, were eaten in any considerable quantity, it would 

 prove injurious to any delicate constitution, in consequence 

 merely of the large amount which it contains of this alkaline 

 substance ; and if such a consequence as this may follow, even 

 in the case of the most carefully baked gingerbread, it is plain 

 that, in the hands of a careless or unskilful mechanic, the em- 

 ployment of such an ingredient is extremely inconvenient. It 



