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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Cocoa bean fermentation | 1/3 | https://en.wikipedia.org/wiki/Cocoa_bean_fermentation | reference | science, encyclopedia | 2026-05-05T14:15:07.650805+00:00 | kb-cron |
Fermentation is an important step in processing cocoa beans to make chocolate. In fermentation, beans that have been removed from their pods are put together in close proximity. Yeasts, lactic acid bacteria and acetic acid bacteria break down pulp surrounding the beans and develop flavor precursors within the bean that create chocolate flavors during roasting. The process also reduces bitterness and gives beans a more brown hue. Fermentation is divided between on-farm and centralized processing, with the former more common in West Africa and the latter more common in the Americas and parts of the Asia Pacific. In on-farm processing, which is how most fermentation has historically been undertaken, farmers wrap beans in leaves for around five days or move them between wooden boxes daily. In some countries such as Indonesia, cocoa beans undergo minimal fermentation and are sold as bulk filler.
== Process ==
=== Background ===
Theobroma cacao is a small tree which grows within 20° of each side of the equator. Its fruits, cocoa pods, grow along its trunk and thicker branches, and are cut down with knives and machetes when ripe. These pods are cut or cracked open using knives or clubs, revealing 30–45 oval beans (the seed of the plant) covered in a white pulp. These beans are removed by hand, and they are detached from the placenta.
=== Procedure ===
In the fermentation process, mature cocoa beans are stored close together. As they ferment, yeast and bacteria in the pulp multiply and break down sugars and mucilage. Broken down, much of the pulp liquifies, draining away. How beans are stored together depends on where in the world the beans are being fermented. Smallholders, such as those who dominate production in West Africa, generally store beans in piles weighting up to 25–2,500 kilograms (55–5,512 lb), which are then covered by banana leaves. The leaves' waxiness retains the heat generated by the ferment. Smallholders in Southeast Asia, the Americas and some of West Africa also ferment beans in buckets and baskets. In plantations and large fermentaries, most fermentation is undertaken in large wooden boxes which hold 1,000–2,000 kilograms (2,200–4,400 lb) of cocoa beans. Some of these are outfitted with openings to permit airflow and to allow the pulp to drain. During a typical ferment, beans are moved daily between boxes to facilitate airflow and standardise output. This practice of agitating beans during a ferment occurs to a lesser extent, and with less frequency, among beans being fermented in piles. While ferments generally take around five days, the end point for smallholders is ultimately determined by their experience. Plantations are more likely to ferment for longer than five days, with some extending the process to six or seven days. In determining how long to ferment, producers try to avoid overfermention, which causes beans to take on a "hammy" off-flavor. The level of fermentation is assessed using a generally subjective and unreliable method called the "cut test", wherein a set of beans are bifurcated and quantities of different colors are counted.
=== Microbiology ===
During fermentation, the bean embryo is killed by heat and acidity generated by microbes, providing for an environment where flavor precursors can develop. When beans are removed from their pods, they are naturally exposed to these microbes from the environment, most importantly anaerobic yeasts, lactic acid bacteria, and acetic acid bacteria. While all are present from the beginning of the fermentation, the role of each has more significance in different stages of a fermentation. Anaerobic yeasts are most prominent during the first 24–36 hours, where they convert sugars in the pulp to alcohol and carbon dioxide in highly acidic and low oxygen conditions. The carbon dioxide produced displaces air, keeping fermentation conditions anaerobic. As yeasts break down more of the pulp, the beans are increasingly exposed to air, allowing acetic acid bacteria to become more active. These bacteria consume alcohol the yeasts have produced, producing acetic acid and increasing the temperature, in some reactions to over 50 °C (122 °F). These acidic and hot conditions kill the bean. After 4–5 days, lactic acid forms as lactic acid bacteria consume sugars and organic acids. As the temperature decreases around day four and acetic acid production slows, oxygen enters the environment, flowing over the beans. This permits aerobic reactions to occur, including the conversion of polyphenols into insoluble polymers. As of 2013, the complexity of the process meant the number of reactions that occur during fermentation was unknown.
=== Bacterial contamination === The warm environment of part of the fermentation process permits the growth of thermophilic bacteria, primarily those in the genus Bacillus. Contamination during and before the fermentation process can introduce Salmonella. This is managed through roasting and/or by debacterisation. Overfermentation occurs as microbes that thrive in aerobic conditions found at the end of fermentation increase the acidic content and turn the beans black.