o4 Memoir upon Coffee. 
fron roasted coffee } this water was saturated with the aroma 
of the coffee, and it carried with it some particles of concrete 
essential oil, like that obtained from the distillation of dry 
coffee, The re-azents did not demonstrate the abe 3 of 
any substance in solution in this water. 
Infusions and Decoctions compared.—Iin order to ascertain 
the different solubility of the principles of coffee, it remained 
to submit the same roasted powder to the successive action . 
of infusion and decoction. I therefore placed two ounces 
of coffee in a filter, I poured cold water upon it until the 
re-ayents ceased to indicate to me the presence of any mat- 
ters in solution. Sixty-eight ounces of cold water must have 
been employed to clear this coffee of its soluble matter. T 
divided these washings into seventeen portions of four ounces 
each, as they came thtoudh the filter, “All’ these seventeen 
portions contained the allie acid in proportion to their order 
of priority ; the four first contained gum, and the first alone 
precipitated the solution of size, which showed the presence 
of tannin, : 
The coffee, withdrawn from the filter, was dried in a 
stove; I afterwards poured upon it eight ounces of water 
heated to 75° (167° of Fahr.); the smell of this secondary 
infusion was agreeable, but weaker than that of coffee which 
is prepared for the table : when examined by the re-agents 
it furnished a little mucilage and a good deal of gallic acid, 
1 found neither tannin nor resin in It. 
I took once more-the same coffee, washed cold and in- 
fused warm as above described, and boiled it in six ounces 
of water until it was reduced to four. This decoction con 
tained a great deal of gum and gallic acid, little aroma, and 
yielded by the re-agents no signs of tannin or resin, 
Olservations, 
~ 
These experiments prove that cold water clears roasted 
coffee of the little tannin which it contains, of a part of its 
extractive matter, of a great part of its aroma;-but it only 
takes off a small postion of its gallic.acid and its gum. We 
have already seen that a warm infusion is more saturated 
with these last principles, but that its aroma is weaker. In 
short, 
