mpensated by improvement in quality and consequent enhancement of
value.

_Roasting._--In the process of roasting, coffee seeds swell up by the
liberation of gases within their substance,--their weight decreasing in
proportion to the extent to which the operation is carried. Roasting
also develops with the aromatic caffeone above alluded to a bitter
soluble principle, and it liberates a portion of the caffeine from its
combination with the caffetannic acid. Roasting is an operation of the
greatest nicety, and one, moreover, of a crucial nature, for equally by
insufficient and by excessive roasting much of the aroma of the coffee
is lost; and its infusion is neither agreeable to the palate nor
exhilarating in its influence. The roaster must judge of the amount of
heat required for the adequate roasting of different qualities, and
while that is variable, the range of roasting temperature proper for
individual kinds is only narrow. In continental countries it is the
practice to roast in small quantities, and thus the whole charge is well
under the control of the roaster; but in Britain large roasts are the
rule, in dealing with which much difficulty is experienced in producing
uniform torrefaction, and in stopping the process at the proper moment.
The coffee-roasting apparatus is usually a malleable iron cylinder
mounted to revolve over the fire on a hollow axle which allows the
escape of gases generated during torrefaction. The roasting of coffee
should be done as short a time as practicable before the grinding for
use, and as ground coffee especially parts rapidly with its aroma, the
grinding should only be done when coffee is about to be prepared.

_Adulteration._--Although by microscopic, physical and chemical tests
the purity of coffee can be determined with perfect certainty, yet
ground coffee is subjected to many and extensive adulterations (see also
ADULTERATION). Chief among the adulterant substances, if it can be so
called, is chicory; but it occupies a peculiar position, since very many
people on the European continent as well as in Great Britain
deliberately prefer a mixture of chicory with coffee to pure coffee.
Chicory is indeed destitute of the stimulant alkaloid and essential oil
for which coffee is valued; but the facts that it has stood the test of
prolonged and extended use, and that its infusion is, in some
localities, used alone, indicate that it performs some useful function
in connexion with coffee,