series
of steps, so that the cacao is transferred with little labour from the
higher to the lower. In San Thome the cacao is placed on the plantation
direct into trucks, which are covered with plaintain leaves, and run on
rails through the plantation right into the fermentary. Some day some
enterprising firm will build a fermentary in portable sections easily
erected, and with some simple mechanical mixer to replace the present
laborious method of turning the beans by manual labour.

The general conditions[1] for a good fermentation are:

(1) The mass of beans must be kept warm.

(2) The mass of beans must be moist, but not sodden.

(3) In the later stages there must be sufficient air.

(4) The boxes must be kept clean.

[1] For full details see the pamphlet by the author on _The
Practice of Fermentation in Trinidad_.

_Changes during Fermentation._

No entirely satisfactory theory of the changes in cacao due to
fermentation has yet been established. It is known that the sugary pulp
outside the beans ferments in a similar way to other fruit pulp, save
that for a yeast fermentation the temperature rises unusually high (in
three days to 47 degrees C.), and also that there are parallel and more
important changes in the interior of the bean. The difficulty of
establishing a complete theory of fermentation of cacao has not daunted
the scientists, for they know that the roses of philosophy are gathered
by just those who can grasp the thorniest problems. Success, however, is
so far only partial, as can be seen by consulting the best introduction
on the subject, the admirable collection of essays on _The Fermentation
of Cacao_, edited by H. Hamel Smith. Here the reader will find the
valuable contributions of Fickendey, Loew, Nicholls, Preyer, Schulte im
Hofe, and Sack.

The obvious changes which occur in the breaking down of the fruity
exterior of the bean should be carefully distinguished from the subtle
changes in the bean itself. Let us consider them separately:--

(_a_) _Changes in the Pulp._--Just as grape-pulp ferments and changes to
wine, and just as weak wine if left exposed becomes sour; so the fruity
sugary pulp outside the cacao bean on exposure gives off bubbles of
carbon dioxide, becomes alcoholic, and later becomes acid. The acid
produced is generally the pleasant vinegar acid (acetic acid), but under
some circumstances it may be lactic acid, or the rancid-smelling butyric
acid. Kismet