making:

VARIOUS ASPECTS OF SCIENTIFIC COFFEE BREWING

Before converting it into the beverage form, coffee must be
carefully selected and blended, and skillfully roasted, in order
thus far to assure obtaining a maximum efficiency of results. No
matter how accurately all this be done, improper brewing of the
roasted bean will nullify the previous efforts and spoil the drink;
for roasted coffee is a delicate material, very susceptible to
deterioration and of doubtful worth as the source of a beverage
unless properly handled.

There probably never was produced a drink which so fits into the
exacting desires of the human appetite as does coffee. Properly
prepared, it is a delightful beverage: but incorrectly made, it
becomes an imposition upon the palates of mankind. Sensitive though
coffee is to improper manipulation, the best procedure for brewing
it is also the easiest. Cheap coffee well made excels good coffee
poorly made.

CONSTITUENT CONCEPTS. The roasting of green coffee causes an
alteration in the constitution of its constituents, with the result
that some of the compounds present therein which were originally
water-soluble are rendered insoluble, and some which were insoluble
are converted into soluble ones. A portion of the original caffein
content is lost by sublimation. The aromatic conglomerate, caffeol,
is formed, and a considerable quantity of gas is produced, a
portion of which, developing pressure in the cells of the beans,
pops, or swells, them so as to increase the size of each individual
bean. The constituents which are water-soluble after the
torrefaction may be generally classified as heavy extractives and
light aromatic materials. The percentages and nature of these
materials in the roasted coffee will vary with the type of coffee
and with the roast which it is given. In general, and in particular
for purposes of comparison of methods of brewing, they may be
considered to be the same and to occur in about the same
proportions in all coffees.

The heavy extractives are caffein, mineral matter, proteins,
caramel and sugars, "caffetannic acid", and various organic
materials of uncertain composition. Some fat will also be found in
the average coffee brew, being present not by virtue of being water
soluble, but becau