Cocoa Fermentation

Post-Harvest Management

Cocoa pods should be opened carefully to avoid damaging or contaminating the beans. Once enough pods have been harvested, the beans should be extracted promptly—ideally at once and no later than two days after harvest—to reduce losses from disease.

Fresh beans and their mucilage should be kept in a clean container or plastic bag when transportation is necessary. Small, cut, flat, or stuck-together beans should be processed separately because they can reduce the appearance and overall quality of the finished cocoa.

Cocoa Fermentation

Fermentation is one of the processes that most strongly influences cocoa quality because it helps develop the characteristic flavor and aroma of the beans.

The beans are fermented in wooden boxes with openings that allow liquid from the mucilage to drain. The boxes should be kept under cover and protected from strong air currents and animals.

Fermentation generally lasts five to six days. The cocoa mass is turned on the second, fourth, and fifth days to introduce oxygen and promote more uniform fermentation.

During fermentation, the mucilage breaks down, the temperature rises, the seed embryo dies, and flavor and aroma precursors develop within the beans. Properly fermented beans should appear swollen and have darker skins.

The beans should not be washed before fermentation. Excessive fermentation should also be avoided because it can cause decomposition, excessive acidity, and undesirable flavors that are difficult to remove during manufacturing.

The Fermentation Process

Cocoa fermentation is natural or spontaneous. Microorganisms are not deliberately added to the beans; instead, they enter from the pod surfaces, tools, containers, surrounding environment, and the hands of the people handling the cocoa.

The microbial succession begins with yeasts, followed by lactic-acid bacteria and then acetic-acid bacteria. Other microorganisms, including species of Bacillus and enterobacteria, may also participate.

These microorganisms act primarily on the pulp surrounding the beans. The pulp contains glucose, fructose, and sucrose and initially has an acidic pH of approximately 3.3 to 4.0 because of its citric-acid content.

Drying After Fermentation

Drying serves four principal purposes:

1. Reducing the beans’ water content.
2. Preventing seed germination.
3. Preserving and developing the required bean quality.
4. Reaching a moisture level that discourages bacteria and fungi.

Humidity, temperature, and drying time must be controlled. Excessive heat or prolonged drying can scorch or roast the beans, while insufficient drying leaves too much moisture for safe storage.

Storage and Bean Selection

Beans should be sorted according to quality and size. Larger beans are treated as premium grades, while smaller beans can be separated with appropriately sized sieves. The source identifies a number-six cocoa screen for this classification.