Cocoa and Chocolate: Their History from Plantation to Consumer

by Arthur William Knapp

DIAGRAM OF CACAO BEAN CLEANING MACHINE.
This is a box fitted with shaking sieves down which the cacao beans pass in a current of air. Having come over some large and very powerful magnets, which take out any nails or fragments of iron, they fall on to a sieve (1/4-inch holes) which the engineer describes as "rapidly reciprocating and arranged on a slight incline and mounted on spring bars." This allows grit to pass through. The beans then roll down a plane on to a sieve (3/8-inch holes) which separates the broken beans, and finally on to a sieve with oblong holes which allows the beans to fall through whilst retaining the clusters. The beans encounter a strong blast of air which brushes from them any shell or dust clinging to them.

(c) Roasting the Beans.

As with coffee so with cacao, the characteristic flavour and aroma are only developed on roasting. Messrs. Bainbridge and Davies (chemists to Messrs. Rowntree) have shown that the aroma of cacao is chiefly due to an amazingly minute quantity (0.0006 per cent.) of linalool, a colourless liquid with a powerful fragrant odour, a modification of which occurs in bergamot, coriander and lavender. Everyone notices the aromatic odour which permeates the atmosphere round a chocolate factory. This odour is a bye-product of the roasting shop; possibly some day an enterprising chemist will prevent its escape or capture it, and sell it in bottles for flavouring confectionery, but for the present it serves only to announce in an appetising way the presence of a cocoa or chocolate works.

SECTION THROUGH GAS HEATED CACAO ROASTER.

Roasting is a delicate operation requiring experience and discretion. Even in these days of scientific management it remains as much an art as a science. It is conducted in revolving drums to ensure constant agitation, the drums being heated either over coke fires or by gas. Less frequently the heating is effected by a hot blast of air or by having inside the drum a number of pipes containing super-heated steam.

ROASTING CACAO BEANS.
(Messrs. Cadbury Bros'. Works, Bournville).