the reaction between
acrolein and ammonia to give methyl pyridin, which in turn with furfurol
forms furfurol vinyl pyridin. This upon reduction would produce the
alkaloid, conin, traces of which have been found in coffee.

Although furfuraldehyde is the natural decomposition product of
pentosans, furfuryl alcohol is the main furane body of coffee aroma.
This would indicate that active reducing conditions prevail within the
bean during roasting; and the further fact that carbon monoxid is given
off during roasting makes this seem quite probable. If one admits that
caffetannic acid exists in the green bean; that upon oxidation it gives
viridic acid; and that it is concentrated in the outer layers of the
bean, as certain investigators have claimed, then there is chemical
proof of the existence of oxidizing conditions about the exterior of the
bean. In any event, however, the fact that oxidizing conditions
predominate on the external portion of the bean is obvious. Accordingly,
our meager knowledge of the chemistry of roasting indicates that while
the external layers of the roasting beans are subjected to oxidizing
conditions, reducing ones exist in the interior. Future experimentation
will, no doubt, prove this to be the case.

Attempts have been made to retain in the beans the volatile products,
which normally escape, both by coating previous to roasting[163] and by
conducting the process under pressure.[164] However, the results so
obtained were not practical, since the cup values were decreased in the
majority of cases, and the physiological effects produced were
undesirable. In cases where the quality was improved, the gain was not
sufficient to recompense the roaster for the additional expense and
difficulty of operation.

Various persons have essayed to control the roasting process
automatically; but the extreme variance in composition of different
coffees, the effect of changing atmospheric conditions, and the lack of
constancy in the calorific power of fuels have conspired to defeat the
automatic roasting machine.[165] It is even doubtful whether De
Mattia's[166] process for roasting until the vapors evolved produce a
violet color when passed into a solution of fuchsin decolorized with
sulphur dioxid is commercially reliable.

Many patents have been granted for the treatment of coffees immediately
prior to or during roasting with the object of thus improving the
product. The majority of these depend upon adding