DETECTION OF ADULTERATED COFFEE. 909 
tionable. There is not sufficient evidence against chicory to warrant 
placing it in the list of objectionable substances. Obvious adulterants 
of coffees are the so-called substitutes molded in imitation of the genuine 
beans. 
ADULTERANTS AND THEIR DETECTION. 
Facing or coloring.—It is not an uncommon practice to treat inferior 
or damaged coffees by some process for the improvement of their 
appearance and in imitation of superior grades. Java seems to have 
been especially subject to this treatment, or rather other coffees are 
colored in imitation of Java. E. Waller states! that South American 
cofiees are often exposed toa high, moist heat, which changes their color 
from green to brown, thus forming imitation Java. Waller also men- 
tions the use of pigments in coloring coffees. This chemist found one 
twenty-fourth grain of Scheele’s green per one-half ounce of coffee. He 
also reports the use in the Brooklyn mills of yellow ocher, silesian blue, 
chrome yellow, burnt umber, venetian red, drop black, charcoal, and 
French black. Coftee is polished by rotation in cylinders with soap- 
stone. 
The following? is another method of preparing imitation Javas. Raw 
coffee, which has been damaged by sea water, is washed, decolorized 
with lime water, again washed, rapidly dried, and colored by a slight 
roasting or by means of azo-orange. By this method Santos coffees 
are converted into imitation Javas. The weight lost is regained by 
steaming, and then coating the beans with glycerine, palm oil, or vase- 
line to prevent evaporation. 
Coffees are sometimes faced with Prussian blue or indigo, lead chro- 
mate, etc. The following list of facing mixtures is from the published 
investigations of K. Sykora.° 
(1) Mixture of indigo, lead chromate, coal, and clay. 
(2) (Approximately) 5 parts indigo, 10 parts coal, 4.5 parts lead chro- 
mate, 65.5 parts clay, and 15 parts ultramarine. 
(3) (Approximately) 5 parts indigo with some yellow dye, 3 parts 
coal, 8 parts lead chromate, 82 parts clay, 2 parts ultramarine. 
(4) (Approximately) 12 parts indigo and some yellow dye, 5.5 parts 
coal, 4.5 parts lead chromate, 6.6 parts clay, and 12 parts ultramarine. 
A mixture examined by G. C. Wittstein* was composed of 15 parts 
Prussian blue (or indigo), 35 parts lead chromate, 35 parts clay and 
gypsum, and 15 parts water. According to Nanning, coffee beans are 
colored blue by shaking with finely powered iron. 
Indigo and Prussian blue may be detected by the microscope or 
chemically (see page 881 for methods). Lead chromate should be ex- 
— 
! Analyst, 9, 128. 
> Bull. de la Soc. Chim. de Paris, 47, 7; Chem. News, 56, 24. 
3 Chem. Centrbl., 1887, No. 47; Rep. f. anal. Chem., 1887, 765. 
4Chem. News, 33, 194. 
