7 6 
SCIENCE. 
hour, somewhat of their aroma in consequence of the in- 
fluence of the oxygen of the air, the porosity of the 
roasted berries allowing it to penetrate easily. Liebig 
recommended a process by which much of this pernicious 
change can be avoided. “ Strew,” says he, “ over the 
berries, when the roasting has been completed, and while 
the vessel in which it has been done is still hot, some 
powdered white or brown sugar ; half an ounce to one 
pound of coffee is sufficient.” 
The sugar melts immediately, and by well shaking, or 
turning the roaster quickly, it spreads over all the berries, 
and gives each one a fine glaze, impervi jus to the atmos- 
phere. 
They have then a shining appearance, as though cov- 
ered with a varnish, and in consequence lose their odor 
entirely, which, however, returns in a high degree, as 
soon as they are ground. 
After this operation, they are to be shaken out rapidly 
from the roaster, and spread on a cold plate of iron, so 
that they may cool as soon as possible. 
If the hot berries are allowed to remain heaped to- 
gether, they begin to sweat, and when the quantity is large, 
the heating process by the influence of the air increases 
to such a degree, that the coffee is permanently damaged.” 
In this city I have often observed that coffee is 
roasted to too high a color, and filled into sacks too 
quickly, before the process of cooling is complete. 
The preparation of coffee as a beverage is accomplished 
by three processes : first, by filtration ; second, by infu- 
sion ; and third, by boiling. 
Liebig states that filtration gives often, but not always, a 
good cup of coffee. When pouring ihe boiling water over 
the ground coffee is done slowly, the drops in passing 
come in contact with too much air, whose oxygen works 
a change in the aromatic particles, and often destroys 
them entirely. 
The extraction moreover is incomplete ; instead of 20 
to 21 per cent., the water dissolves only 1 1 to 1 5 per cent., 
and 7 to 10 per cent, is lost. 
Infusion is accomplished by making the water boil and 
then putting in the ground coffee, the vessel being imme- 
diately taken off the fire and allowed to stand quietly for 
about 10 minutes. 
1 his method gives a very aromatic coffee, but one con- 
ta ning very little extract. 
Boiling is the custom in the East, and yields excellent 
coffee. The powder is added to the water when cold, and 
then placed over the fire and merely allowed to boil a few 
seconds. The fine particles of coffee are drunk with the 
beverage. It boiled long, the aromatic parts are volatil- 
ized and the coffee is then rich in extract, but poor in 
aroma. 
Further, Liebig gives what he calls the best method ; 
th s I produce, not because 1 think the plan will make a 
coffee acceptable to most palates, but because Liebig 
speaks highly in its praise, and states that it is without 
those heating properties, common to most preparations, 
causing it to be rejected by many in delicate health. 
“ My method,” said Leibig,“ is the union of the second 
and third. The usual quantities of coffee and water are to 
be retained ; a tin measure containing half an ounce of 
green berries, wheu filled with roasted ones, is generally 
sufficient for two small cups of moderate strength, or 
one so-called breakfast cup ; one pound of green ber- 
ries, equal to 16 ounces, yielding after roasting 24 tin 
measures (of y z ounce each) lor 48 small cups of coffee. 
With three-fourths of the coffee to be employed, 
(after being ground), the water is made to boil for 10 or 
15 minutes. 
The one-quarter of the coffee which has been kept 
back, is then flung in, and the vessel immediately with- 
drawn from the fire, covered over and allowed to stand 
from five to six minutes. 
In order that the powder on the surface may fall to 
the bottom, it is stirred around, the deposit then takes 
place, and the coffee poured off ready for use. In order 
to separate the dregs more completely, the coffee may 
be passed through a clean cloth, but generally this is not 
necessary and often prejudicial to the pure flavor of the 
beverage. 
The first boiling gives the strength, the second addi- 
tion the flavor. The water does not dissolve more than 
the fourth part of the aromatic substances contained in 
the roasted coffee. 
The beverage when ready ought to be of a brown black 
color, somewhat like chocolate thinned with water; this 
want of clearness in coffee thus prepared, does not come 
from the fine grounds, but from a peculiar fat resembling 
butter, about 12 per cent, of the amount the berries 
contain, and which, if over roasted, is partly destroyed. 
In the other methods of making coffee, more than 
half of the valuable parts of the berries remain in the 
grounds, and is lost. 
“Judging,” said Liebig, “ as favorably of my coffee as I 
do myself, its taste is not to be compared with that of 
the ordinary beverage, but the good effects which my 
coffee has on the organism should be taken into con- 
sideration. 
Many persons who connect the idea of strength or con- 
centration, w.th a dark color, fancy my coffee to be thin 
and weak, but these were at once more favorably in- 
clined, when I gave it a dark color by means of burnt 
sugar.” 
Adulteration of coffee sold in a ground state, is largely 
carried on, especially of that sold to the poorer classes 
— out of 34 samples purchased by an English analytical 
chemist in London, 31 contained chickory, chickory 
itself being adulterated with all manner of compounds. 
There is no falling back, says Dr. Hopall, upon tea and 
chocolate, as these seem rather worse off than the coffee. 
Tea is not only adulterated here, but in China, while as 
to chocolate, the processes employed in corrupting that 
manufacture, are described as “ diabolical.” It is often 
mixed with brick dust to the amount of 10 per cent., 
ochre 12 percent., and peroxide of iron 22 per cent., and 
animal fats of the worst description, while the names 
“Flake,” “Rock,” “Granulated,” “Soluble,” “Dietetic,” 
are merely employed as disguises to cover the fact that 
they are compounds of sugar, starch and other sub- 
stances. 
The microscope is the most effective instrument in the 
work of detecting adulterations, the microscopic ap- 
pearance of coffee and chickory being very distinctive, 
while the presence of starch granules discovers the par 
ticular cereal employed in adulterations. 
The adulteration of coffee by the addition of chicory 
is fraudulent but harmless, chickory containing little that 
is injurious to the system; coffee indeed is the more 
active substance of the two ; its effects on some delicate 
constitutions being so strongly manifested, that without 
a violation of language, it may almost be designated a 
weak poison. 
Some persons positively like the flavor of chickory, 
others deest it; its presence, however, can be at once 
detected by its peculiar odor, and if thrown into cold 
water it imparts a deep tint, which coffee does not. 
In conclusion, I offer a useful receipt of Leibig’s for 
preparing coffee in a ground form for special cases, such 
as marches and journeys, where it is inconvenient to be 
burdened with the necessary machines for roasting and 
grinding ; by this process its aromatic properties can be 
preserved. 
One pound of the roasted berries is reduced to powder, 
and immediately wetted with a syrup of sugar, obtained 
by pouring on three ounces of sugar, two ounces of 
water, and letting them stand a few minutes. 
When the coffee powder is thoroughly wetted with the 
