220 SUBSTITUTES AND ADULTERANTS. 



is first made, and then a second operation when the 

 quantity is approximately known to make a delicate and 

 careful reading of the exact point. Thus if lOO parts of 

 coffee when infused yield sensibly more than i per cent, 

 of sugar, then the presence of chicory or other adulter- 

 ant maybe strongly suspected and a rough calculation of 

 the quantity made. The fact that coffee extract is devoid 

 or almost devoid of sugar, while many of the other 

 natural products yield saccharine extracts, makes itself 

 manifest in many ways, and the specific gravity also of 

 equal quantities of an infusion of coffee being very much 

 lower than the specific gravity of an infusion of chicory 

 and the other principal substances used in the adultera- 

 tion of ground coffee. Chicory also possessing greater 

 coloring power than coffee, for which reason this charac- 

 ter may be rendered available in the testing of coffee, as 

 not only does chicory color water more deeply than 

 coffee, but it colors it with greater rapidity, the oil con- 

 tained in the coffee hindering the solution of the coloring 

 matter by the water, whereas chicory, which contains no 

 oil, imparts its coloring matter to water with great readi- 

 ness. All of which tends to render the color-test, when 

 properly applied, the easiest and most available for the 

 detection of chicory or other substances in coffee. 



What is known as the " Ash test," is as follows : Pure 

 coffee when incinerated or burned, yields about 4 per 

 cent, of ash on an average, while the ash of chicory and 

 other adulterants used in coffee amounts to between 5 

 and 6 per cent, of the residue, the ratio of soluble to 

 insoluble ash being inverted when dissolved in water 

 thus : 



Ash of Coffee. Ash of Chicory. 



Soluble, . . . . 3.24 Soluble, .... 1.74 



Insoluble, . . . 0.76 Insoluble, . , . 3.52 



