BAKING POWDERS. 621 



especially if the alum is used with but a small proportion of its water of 

 crystallization driven off. If the second is true, the object is not ob- 

 tained, of course, for the more filling used the greater the quantity of 

 powder required to produce the same aerating effect, and as for the 

 third, alum and soda are about as cheap as starch. 



It must be remembered that the percentages of starch given in the 

 tables represent anhydrous starch. 



DOMESTIC BAKING-POWDERS." 



It may be asked, can not the consumer make up his own baking-pow- 

 ders? The difficulties in the way of doing this may be enumerated as 

 follows : 



(1) The chemicals in the market, as purchased by the consumer, may 

 not be pure, or of full strength, so that when combined in proper pro- 

 portions they do not give good results. 



(2) The proper proportions to use, and the necessity of thorough mix- 

 ing to secure good results, would not be well understood by any one 

 who was not a chemist. 



(3) In order to prevent the action of the ingredients upon one another, 

 and to preserve the strength of the powder unimpaired as long as pos- 

 sible, the inanufacturertfn'es all his chemicals before mixing them, so as 

 to drive off most of the adhering moisture. Baking-soda can not be dried 

 much, as it loses its carbonic acid, and consequently its efficiency, at 

 very low temperatures. The starch, however, containing as it does 

 from 10 to 18 per cent, of moisture, can be thoroughly dried at 100 to 

 105 C., and its efficiency as a filling material greatly increased. The 

 cream of tartar can also be thoroughly dried. This operation of drying 

 chemicals at a temperature below that at which decomposition would 

 occur seems rather too elaborate an operation for the kitchen. 



These difficulties are more apparent than real, however. In answer 

 to the first, it may be said that the bitartrate is the only chemical which 

 is likely to be adulterated, and as there is no difficulty nowadays in ob- 

 taining a pure article in the wholesale market, it only requires the proper 

 enforcement of adulteration laws to oblige the retailer to furnish a good 

 article. The second objection may be met by furnishing the public 

 simple formulae for compounding such powders, and the third, which is 

 doubtless the most serious, I believe can be overcome by using a larger 

 proportion of filling, without drying the chemicals. 



In the present days of cooking-schools, when so much interest is taken 

 in the preparation of food, and in all branches of the culinary art, it may 

 not be amiss to devote a little space to the discussion of this subject, 

 although it is not, perhaps, strictly within the scope of the present in- 

 vestigation. 



With a view of determining the possibility of making up baking-pow- 

 ders from a simple formula that could be used in the household, and 



