as soon as this is broken, deterioration
sets in. On this account, coffee should be ground immediately before
extraction if maximum efficiency is to be obtained. The cells of the
beans tend to retain the fugacious aromatic principles to a certain
extent; so that the more of these which are broken in grinding, the
greater will be the initial loss and the more rapid the vitiation of the
coffee. It might, therefore, seem desirable to grind coarsely in order
to avoid this as much as possible. However, the coarser the grind, the
slower and more incomplete will be the extraction. A patent[177] has
been granted for a grind which contains about 90 percent fine coffee and
10 percent coarse, the patentee's claim being that in his "irregular
grind" the coarse coffee retains enough of the volatile constituents to
flavor the beverage, while the fine coffee gives a very high
extraction, thus giving an efficient brew without sacrificing
individuality.

In packaging roasted coffee the whole bean is naturally the best form to
employ, but if the coffee is ground first, King[178] found that
deterioration is most rapid with the coarse ground coffee, the speed
decreasing with the size of the ground particles. He explains this on
the ground of "ventilation"--the finer the grind, the closer the
particles pack together, the less the circulation of air through the
mass, and the smaller the amount of aroma which is carried away. He also
found that glass makes the best container for coffee, with the tin can,
and the foil-lined bag with an inner lining of glassine, not greatly
inferior.

Considerable publicity has been given recently to the method of packing
coffee in a sealed tin under reduced pressure. While thus packing in a
partial vacuum undoubtedly retards oxidation and precludes escape of
aroma from the original package, it would seem likely to hasten the
initial volatilizing of the aroma. Also, it would appear from
Gould's[179] work that roasted coffee evolves carbon dioxid until a
certain positive pressure is attained, regardless of the initial
pressure in the container. Accordingly, vacuum-packing apparently
enhances decomposition of certain constituents of coffee. Whether this
result is beneficial or otherwise is not quite clear.

_Brewing_

The old-time boiling method of making coffee has gone out of style,
because the average consumer is becoming aware of the fact that it does
not give a drink of maximum efficiency. Boiling the