From the Archives of the Rare Fruit Council of Australia, inc.
by Ted Henty, Lae, P.N.G.


Seasons in Australia are opposite to those in the US. Summer is Dec. Jan. Feb. Autumn is Mar. Apr. May. Winter is June July Aug. Spring is Sept. Oct. Nov.

Processing Cocoa

Scientific name: Theobroma cacao
Family: Malvaceae


Cocoa seeds ('beans') have no chocolate flavour when fresh. In normal plantation practice, flavour is produced by natural fermentation, usually in large (say 1 x 2 m x 1 m high) wooden boxes. The pods are broken, and the beans, with the sweetish pulp surrounding them, decanted into the boxes.

The mass soon begins to ferment, and a good deal of liquid drains away, in the early stages, through holes of about 1 cm diameter in the bottom boards.

After 2 days, the beans are turned out into another box, to mix and aerate them, and this is repeated each day until fermentation is finished, in 6-8 days. The beans are then turned out and dried.

During fermentation, the temperature should rise to about 50°C. Small amounts of beans will not heat sufficiently. The smallest effective size for a box is about 60 x 60 cm, and about 1 m high; this should be filled to at least 60 cm (about 90 kg of wet beans).

As fermentation proceeds, the beans, which are purple inside in the most familiar variety, become lighter in colour and finally brown. In well-fermented cocoa, the seed-coat is loose, and the cotyledons are easily broken into segments.

D.H. Urquhart, in his book Cocoa (Longmans, 1955), describes artificial fermentation, used to assess the flavour of small batches, single pods or even individual beans. The pods were swabbed with an antiseptic, then opened under aseptic conditions. Fermentation was started with a mixed bacterial/yeast culture, or dispensed with; its only effect was as a source of heat, and chocolate flavour could be produced by manipulating the temperature in an incubator. Germination (or its early stage) was found to be essential; dead beans, killed by heat or cold, would not develop flavour.

Urquhart recommends a temperature of 35°C (not above 38 °) for the first 3½ days, rising then to 50°C for another 3 days.
The beans must be in a container of non-reactive material (not metal, but glass, plastic, or un-chipped enamel) in a water-bath (e.g., a laundry copper) for easier temperature control.

A false bottom must be placed in the vessel, to allow separation of liquid, and the beans stirred thoroughly every 24 hours (at least until 24 hours after the rise to 50°C) to remove carbon dioxide.

Probably asepsis is not vital. In the first few days the seeds are alive and can resist infection; after the temperature rises to 50°C, most organisms will be killed anyway.

I have had no personal experience of small-scale fermentation of cocoa. It is to be hoped that someone may build a method on the information given here, and pass on some more explicit advice in the future.



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Bibliography

Henty, Ted, Lae. "Processing cacao." rfcarchives.org.au. Archives of the Rare Fruit Council of Australia. Mar. 1983. Web. 4 Oct. 2014.

Published 4 Oct. 2014 LR
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