£8 Memoir upon Coffee. 
to be moderate if we wish to preserve the aroma, and not 
decompose the acid, the gum, and the resin, if 
Roasting adds a new principle, which is tannin, in very 
small quantity ; the cold infusion is very aromatic, but a 
little charged with mucilage and gallic acid; the warm in- 
fusion preserves the aroma, and the principles dissolved are 
in such proportions as to please the palate; the decection 
has little aroma, and is strongly saturated with gum and 
gallic acid; the resin itself may perhaps be suspended in it; 
it 1s less acreeable than the infusion. 
Bourbon and Martinique coffee present no differences be- 
tween them; but that of Moka, as already remarked, is 
_more aromatic, less gummous, and more resinous. It is 
probable that the resin of coffee, like that of most of the 
astringent vegetables, has peculiar medicinal properties, As 
we cannot obtain it either by the infusion or the aqueous 
decoction, the habitual use of coffee can throw no light upou 
its action in the animal ceconomy ; it belongs to physicians 
alone to make useful experiments on this subject. 
If I may be allowed to draw any precepts from this ana® 
lysis applicable to the ceconomical use of coffee, I should 
say that it is pessible to drink most excellent coffee from all 
the kinds of it known in commerce, provided it is not adul- 
terated. Amateurs require three qualities in the coffee-they 
use; they wish to find an agreeable aroma in it, a slightly 
bitter taste, a fine colour, and a certain density which they 
call body*. {n order to attain all these advantages, I think 
that good coffee ought to be had in the following manner: 
ist, Choose a dry grain, which has no mouldy or sea 
taste. 
ed, Divide the quantity to be roasted into two equal 
parts. ; 
3d, Roast the first part merely until i it fa the colour of 
acid being combined with it and giving a blue or black colour to the vege- 
table, is a very remarkable phenomenon. kt seemed to me to be worthy of 
inquiry, and I made a comparative analysis of the ashes of gallnuts, when I 
also found a remarkable quantity of iron. 
* Some orientalists set so much value on this density that they reduce their 
cofee toa very fine powder, leave the meal in the infusion, and drink it 
thick like soup. Fr 
a f 
