Oct. 1, 1919 Method for Measuring Acidity of Cereal Products 35 



certain inaccuracies of this method. For example, they point out that by 

 boiling the grain material with 96 per cent alcohol certain proteins are 

 coagulated and that in being thus transformed these bodies possess the 

 power either to absorb acids or to combine with them. Part of the grain 

 acidity might thus be occluded and escape detection. However, these 

 authors recommend the above procedure for want of a better means of 

 measuring the quantities of acid originally present in barley or malt. 



ACIDITY VALUES OBTAINED BY THE ICE-WATER METHOD AS COM- 

 PARED WITH THOSE OBTAINED BY THE SCHINDLER METHOD 



The method proposed in this paper was first used during a study on 

 the diastatic power of oats. In that study the ice-water extraction 

 method recommended by Thatcher and Koch {16) was employed; but 

 it was thought necessary to neutralize each oat extract before deter- 

 mining its diastatic strength, inasmuch as the oats in question repre- 

 sented different degrees of soundness and some of them had been 

 subjected to the sulphuring process as now practiced by the trade {13). 

 In neutralizing the different aqueous oat extracts with N/io sodium 

 hydroxid very pronounced differences in acidity were observed in samples 

 which, when the above-mentioned aclohol extraction method of Schindler 

 was used, had shown no appreciable difference in acidity. Furthermore, 

 the values obtained by simple titration of the ice-water extracts appeared 

 to represent the actual acidity of the respective sample far more truly 

 than those obtained by means of the Schindler method. The data com- 

 piled in the subjoined table will serve to illustrate these relations. The 

 second and third columns of figures denote cubic centimeters of normal 

 alkali which were required to neutralize the acidity in the extract from 

 1 ,000 gm. of dry material. 



The samples is to los in the following table represent the same oats 

 as No. I to 10. The latter set had been taken before, and the former 

 after, the sulphur bleaching. These duplicate samples of oats of the 

 1 91 5 crop had been secured by official inspectors at commercial elevators 

 in Chicago. Since most of these oat shipments when arriving at the 

 Chicago market appeared discolored or otherwise damaged, the dealers 

 had tried to improve their appearance by means of sulphuring. 



