EXAMINATION <>K COFFKK. 49 



QOFFBJB, 



There are :i number of simple tests for I lie presence of the adulter- 

 ants of ground coffee. These tests are called simple heeaii-e they can 

 be performed without the facilities of the chemical laboratory, and by 

 one who has not had the experience and training of a chemist. It must 

 be understood, however, that they require careful observation and 

 study, and that one must perform them repeatedly in order to obtain 

 reliable results. Before applying them to the examination of an 

 unknown sample, samples of known character should be secured and 

 studied. Unground coffee may be ground in the home and mixed u ith 

 various kinds of adulterants, which can also be secured separately. 

 Thus the articles themselves in known mixtures may be studied and 

 when the same results are obtained with unknown samples they can be 

 correctly interpreted. Thes^ tests are well known in the laboratory 

 and may be used in the home of the careful housewife who has the 

 time and perseverance to master them. 



PHYSICAL TESTS. 



The difference between the genuine ground coffee and the adulter- 

 ated article can often be detected by simple inspection with the naked 

 eye. This is particularly true if the product be coarsely crushed rather 

 than finely ground. In such condition pure coffee has a quite uniform 

 appearance, whereas the mixtures of peas, beans, cereals, chicory, etc., 

 often disclose their heterogeneous nature to the careful observer. This 

 is particularly true if a magnifying glass be employed. The different 

 articles composing the mixture may then be separated by the point of 

 a penknife. The dark, gummy-looking chicory particles stand out in 

 strong contrast to the other substances used, and their nature can be 

 determined by one who is familiar with them by their astringent taste. 



The appearance of the coffee particles is also quite distinct from that 

 of many of the coffee substitutes employed. The coffee has a dull sur- 

 face, whereas some of its substitutes, especially leguminous products, 

 often present the appearance of having a polished surface. 



After a careful inspection of the sample with the naked eye, or, bet- 

 ter, with a magnifying glass, a portion of it may be placed in a small 

 bottle half full of water and shaken. The bottle is then placed on the 

 table for a moment. Pure coffee contains a large amount of oil, by 

 reason of which the greater portion of the sample will float. All cof- 

 fee substitutes and some particles of coffee sink to the bottom of the 

 liquid. A fair idea of the purity of the sample can often be deter- 

 mined by the proportion of the sample which floats or sinks. 



Chicory contains a substance which dissolves in water, imparting a 

 brownish-red color. When the suspected sample, therefore, is dropped 

 into a glass of water, the grains of chicory which it contains may be 



