Coffee has a high content of mineral substances, and as these are largely soluble they give to the extracted coffee an additional value. Spencer found as the average of the composition of ash of four representative coffees, consisting of Mocha, Maracaibo, Java and Rio, the following data:

Sand.....................................

1 .06

percent

Silica.....................................

0.84

percent

Ferric Oxid...............................

1.18

percent

Lime.....................................

5.51

percent

Magnesia.................................................................

10.98

percent

Potash ...................................................................

61.84

percent

Soda.....................................

0.36

percent

Phosphoric acid...........................

12.94

percent

Sulphuric acid.............................

4.63

percent

Chlorin....................................................................

0.76

percent