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Cocoa, coffee and spice from West Africa

Cocoa bean fermentation

Fresh cocoa beans are scooped from the pod with their sweet white pulp and piled in heaps or boxes under banana leaves for four to seven days. Yeasts, then lactic and acetic acid bacteria ferment the pulp, the heat and acid kill the bean, and the beans are then sun-dried. This is where the precursors of chocolate flavour form.

Fully documentedCocoa, coffee and spice15 days – 26 days

Recipe

Amounts from a sourceAmounts describe farm heaps in a Ghanaian field study. Other farms use 100–200 kg heaps or wooden boxes of about 1,700 kg; there is no fixed recipe beyond beans, pulp and leaves.
Fresh cocoa beans with pulp250–1,000 kg per heapPulp is about 12% sugars, pH 3.3–4.0, up to 10% pectin[camu2007][codex-cocoa]
Banana or plantain leavesLaid under and over the heap[camu2007][icco]
No starterThe microbes come from the surroundings, mainly the surfaces of the pods and the baskets used; early contaminants may also come from banana leaves, tools and farmers' hands[camu2008][camu2007]
Starterspontaneous

Total time across the recorded steps: 15 days – 26 days

Start
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pH 3.3–4

What changes: Starting material: fresh cocoa beans in their white pulp

Step 1 of 6
Open the pods and scoop out beans and pulp
Time
Not documented
Temperature
Not documented
Salt
None given
Acidity
pH 3.3–4
Reported
Which microbes the steps name, step by step
Yeasts
Lactic acid bacteria
Acetic acid bacteria
Saccharomyces cerevisiae
L. plantarum

Output: wet beans with pulp.

Flavour
Not documented
Texture
wet beans in white, slimy pulp
Colour
white pulp; purple bean inside

Microbes at work in this step

Not documented for this step.

Method

Measured measured in a studySet fixed by a specification or tested recipeReported one source reports itTypical a general value, not sourced for this fermentUnconfirmed not yet checked against a source

At a glance

Fresh cocoa beans are scooped from the pod with their sweet white pulp and piled in heaps or boxes under banana leaves for four to seven days. Yeasts, then lactic and acetic acid bacteria ferment the pulp, the heat and acid kill the bean, and the beans are then sun-dried. This is where the precursors of chocolate flavour form. Made in 6 steps over 15 days – 26 days. The longest step, sun-dry on raised surfaces, takes 7–14 days (Camu N. et al. 2008) and runs at up to 65 °C (International Cocoa Organization (ICCO)). Yeasts and Lactiplantibacillus plantarum do most of the fermenting.

Key numbers
Main step7–14 daysReported[camu2008][camu2007]Sun-dry on raised surfaces
Temperatureup to 65 °CReported[icco]Sun-dry on raised surfaces
AciditypH 6.5 → 4.5Reported[fao134]The bean dies and browns inside

What makes this one different

Cocoa is fermented on the farm as a whole fruit mass. The microbes work only in the pulp; inside the bean, acid and heat from the pulp kill the seed and its own enzymes make the flavour precursors. The main split is heap versus box, and how often the mass is turned.

Related ferments

Variants

  • Heap (West Africa)100–1,000 kg on banana leaves; often turned once or not at all; 5–6 days by Ghanaian advice.
  • BoxIn one Costa Rican study, boxes of 1.4 × 2.0 × 0.6 m held about 1,700 kg, were left for 48 h and then mixed daily. FAO Bulletin 134 says boxes give a more even fermentation than heaps.
  • Basket, tray and platformThe Codex code lists baskets, trays and platforms, with boxes and heaps, as containers for the beans and pulp.
  • Criollo versus ForasteroCriollo needs about 2–3 days; Forastero about 5.
  • Starter-culture fermentationSelected strains are added for a better-controlled fermentation; a study of Ivorian acetic acid bacteria argues that starter selection matters because strains behave so differently.
  • Cacao pulp drinksHenderson et al. argue that the earliest Honduran cacao use was probably a fermented pulp drink, which can reach up to 5% alcohol, but the residues cannot show whether pulp or seed was used.

Safety

Ochratoxin A is made by Aspergillus moulds when fermentation or drying goes wrong. Codex advice is to open pods within 7 days of harvest, ferment 4–7 days and no longer, turn the mass, start drying at once on raised surfaces in layers no deeper than 6 cm, and bring the beans below 8% moisture. Protect drying beans from rain and dew, never re-wet them, and throw out mouldy beans.

Hazards the sources name: Ochratoxin A-producing moulds (Aspergillus carbonarius and the A. niger group; fewer A. westerdijkiae, A. ochraceus and A. melleus).

History and sources

Every number is labelled with how it is known. How this atlas is made

The earliest evidence of cacao use found so far is residue in a pottery bottle from Puerto Escondido, Honduras, dated to after 1150 BCE. The authors argue it was probably a fermented drink made from the pulp, although the chemistry cannot tell pulp from seed.

  1. [codex-cocoa] Codex Alimentarius Commission 2013, Code of practice for the prevention and reduction of ochratoxin A contamination in cocoa, CAC/RCP 72-2013 (copy on the Slovenian government site)spec
  2. [icco] International Cocoa Organization (ICCO), Harvesting and post-harvestgov
  3. [camu2007] Camu N. et al. 2007, Dynamics and biodiversity of populations of lactic acid bacteria and acetic acid bacteria involved in spontaneous heap fermentation of cocoa beans in Ghana, Applied and Environmental Microbiology 73(6):1809–1824, doi:10.1128/AEM.02189-06paper
  4. [camu2008] Camu N. et al. 2008, Influence of turning and environmental contamination on the dynamics of populations of lactic acid and acetic acid bacteria involved in spontaneous cocoa bean heap fermentation in Ghana, Applied and Environmental Microbiology 74(1):86–98, doi:10.1128/AEM.01512-07paper
  5. [verce2021] Verce M. et al. 2021, A combined metagenomics and metatranscriptomics approach to unravel Costa Rican cocoa box fermentation processes, Frontiers in Microbiology 12:641185, doi:10.3389/fmicb.2021.641185paper
  6. [soumahoro2020] Soumahoro S. et al. 2020, Acetic acid bacteria (AAB) involved in cocoa fermentation from Ivory Coast, species diversity and performance in acetic acid production, Journal of Food Science and Technology 57(5):1904–1916, doi:10.1007/s13197-019-04226-2paper
  7. [henderson2007] Henderson J.S. et al. 2007, Chemical and archaeological evidence for the earliest cacao beverages, PNAS 104(48):18937–18940, doi:10.1073/pnas.0708815104paper
  8. [fao134] Battcock M., Azam-Ali S. 1998, Fermented fruits and vegetables. A global perspective, FAO Agricultural Services Bulletin 134, ch. 7, section 7.2 Cocoa productsgov