been shown to be due
to oxygen (activated by an oxidase, a ferment encouraging
combination with oxygen) acting on the astringent
colourless substance, which, like the photographic developer,
pyrogallic acid, becomes brown on oxidation.

(3) _Aroma._ A notable change is that substances are created
within the bean, which _on roasting_ produce the fine
aromatic odour characteristic of cocoa and chocolate, and
which Messrs. Bainbridge and Davies have shown is due to a
trace (0.001 per cent.) of an essential oil over half of
which consists of linalool.[3]

(4) _Stimulating Effect._ It is commonly stated that during
fermentation there is generated theobromine, the alkaloid
which gives cacao its stimulating properties, but the
estimation of theobromine in fermented and unfermented beans
does not support this.

(5) _Consistency._ Fermented beans become crisp on drying.
This development may be due to the "tannins" encountering, in
their dispersion through the bean, proteins, which are thus
converted into bodies which are brittle solids on drying
(compare tanning of hides). The "hide" of the bean may be
similarly "tanned"--the shell certainly becomes leathery
(unless washed)--but a far more probable explanation, in both
cases, is that the gummy bodies in bean and shell set hard on
drying.

[3] _Journal of the Chemical Society_, 1912.

We see, then, that although fermentation was probably originally
followed as the best method of getting rid of the pulp, it has other
effects which are entirely good. It enables the planter to produce a
drier bean, and one which has, when roasted, a finer flavour, colour,
and aroma, than the unfermented. Fermentation is generally considered to
produce so many desirable results that M. Perrot's suggestion[4] of
removing the pulp by treatment with alkali, and thus avoiding
fermentation, has not been enthusiastically received.

[4] _Comptes Rendus_, 1913.

Beans which have been dried direct and those which have been fermented
may be distinguished as follows:

CACAO BEANS

DRIED DIRECT. FERMENTED AND DRIED.

_Shape of bean_ Flat Plumper
_Shell_ Soft and close fitting Crisp and more or
less free.
_Interior: colour_ Slate-blue or mud-brown Bright browns and