The Cocoa Life Cycle from Tree to Bean

Ecology of cocoa. Cocoa is a tropical tree that grows in heavy soils between 0 to 3,000 feet in altitude. Cocoa grows in tropical rainforests with 200 to 300 inches of rain generally between the latitude of 20º north and south of the equator. Because cocoa has a small stature of 30 to 50 feet, it typically grows in the shade of the larger canopy trees of the rainforests. Ecologists call cocoa an understory tree because it exists in the shade of taller trees. This may account for why young cocoa trees require shade for their growth.

Cocoa Trees. The cocoa tree will grow to about 40 to 50 feet tall (10 to 15 m). (1,2) When grown from seed, the tree goes through a juvenile stage in which the first shoot grows straight up for about 6 feet (2 m) with leaves along its length. At this point, at one to two years of age, the tree sends out a whorl of side shoots that form an umbrella-like structure called a jourquette. This is the first stage of the adult plant. The young adult trees will start to flower as early as 18 months but more typically at 2 to 3 years of age. The trees will grow for over 100 years and remain productive, if well cared for.

Cocoa trees were originally found in the wild as an understory tree, growing in the shade of much taller canopy trees in the rainforest. Wild cocoa trees still exist today in the upper reaches of the Amazon basin. Cocoa trees live in a tropical environment, which is not subject to the extreme low winter temperatures of the temperate climates found in North America and Europe. In fact cocoa trees do not tolerate temperatures much lower than about 50ºF. As a consequence, cocoa trees stay green throughout the year and do not go dormant or lose their leaves.

Cocoa Flowers. Cocoa flowers are small, about 3/8 inch (6 mm) in diameter. They are white to pink and contain a central pistil surrounded by stamens. The flowers emerge in bunches from a cushion. These cushions are borne on the trunk and main branches of the tree, a condition called cauliflory which is quite different from temperate crops such as apples or almonds in which the fruit typically will be borne at the end of branches on the second year growth of the tree. (1) Cacao flowers are pollinated by small insects called midges. Many hundreds of flowers will appear on the cocoa trees but only a very small fraction - between 1 to 2% - will ever ripen to become a mature cocoa pod. A pollinated flower will take 180 days to mature into a cocoa pod.

Cocoa Pods. Cocoa pods are the fruit that contain the seeds—also known as cocoa beans. The pods can range between 4 to 16 inches in length and are attached to the trunk and main branches of the tree by a very thick stem (petiole) that is about 3/8 inch (6 mm) in diameter. The cocoa pod has a hard, thick outer rind, much like that of an acorn squash. About 30 to 50 seeds (beans) develop within each pod. Unripe pods are typically green but when they ripen can be yellow, orange, red or purple. Cocoa pods also come in different shapes and different surface textures depending upon the variety.

Cocoa pods will not fall from the tree when ripe, but must be manually removed from the tree at harvest. The strength of the petiole makes it exceedingly difficult to mechanize cocoa harvesting. This fruiting character has led biologists to conclude that the spread of cocoa throughout the tropics of Central and South America was aided by monkeys, squirrels and birds that broke through the pod to gain access to the seeds with their sweet pulp. The animals will then carry off or swallow the seeds, thereby dispersing the cocoa beans as they travel through the forest canopy. Scientists also believe the native peoples of South and Central America spread cacao throughout the region.

Unlike apples or almonds, which are temperate crops which ripen all at the same time, the pods of a cocoa tree typically ripen during two periods of the year creating two separate crops—the main crop and the mid-crop. A good example is in West Africa, where 80% of the cocoa is harvested during the main crop (October to February) and the mid-crop (April to June) during which about 20% of the pods ripen. But even within each crop, not all of the pods ripen at the same time. Because cocoa pods do not ripen in unison, farmers must periodically -- every week or so --walk their cocoa groves to harvest ripe pods.

Cocoa Beans. Once harvested, cocoa pods are broken open using a machete or by breaking the pod open with blunt force by striking on a rock or log. Once pods are opened, the seeds, about the size of an almond, with their adhering pulp are exposed. The cocoa seed and its pulp forms a berry-like structure, botanically described as a “baccate-like seed”.(2) The pulp, initially pure white at harvest, has a soft, juicy covering that has a mild, fruity taste reminiscent of a blend of banana and kiwi flavors. Upon aging, the pulp will turn brown, a process similar to the browning of a freshly cut banana or apple. The pulp contains about 15% natural sugars which form the fuel for the fermentation process.

Contrary to popular belief, not all cocoas are fermented (See Fermentation below). There are traditional people native to Southern Mexico in the state of Oaxaca and also in Venezuela and Panama, who prefer the taste of unfermented cocoa to that of fermented cocoa.(3,4) Other parts of the world that produce unfermented cocoa for international trade include the Dominican Republic and Brazil. In Sulawesi Indonesia, the third largest producer of cocoa in the world, most of the beans are not intentionally fermented or are poorly fermented prior to drying.

Fermentation of Beans. Despite the preferences of the people in Oaxaca, most of the cocoa beans around the world are fermented, from several days to as long as ten days. The process of fermentation does several things. It loosens the shell that surrounds the seed making it easier to remove the cocoa shell during the process of winnowing. Fermentation also reduces the level of bitter components in the seed, helping produce a more mellow tasting chocolate or cocoa powder. Finally fermentation helps to develop flavor precursor compounds that react during bean roasting to form the characteristic, intense cacao flavor. There are basically three ways in which cocoa beans are fermented. 

    Field fermentation is practiced throughout the world and is especially prevalent in Africa. Pods from the surrounding trees are gathered together. A place for a fermentation heap is prepared by either covering the forest floor with banana leaves or with a tarp. The pods are cracked open either with a machete or by striking on a hard object like a rock. The beans are then scooped out of the pod by hand and placed into a fermentation heap ranging in height from 6 inches (15 cm) to 30 inches (80 cm) high. The heaps are then covered with leaves or a tarp. Fermentation begins immediately with the growth of naturally occurring microorganisms that feed on the sugars within the pulp. Within an hour, the outer surface of the pile turns brownish as the enzymes present convert colorless polyphenols to brown-colored compounds. The fermentation pile will heat up as the microbes in the pile increase; heats as high as 140ºF will often be achieved. The fermentation requires oxygen to continue, so farmers, depending upon local customs, will turn the pile of beans with a rake or shovel to introduce air into the pile. Typically a pile of beans will be turned every two days. For example, if the fermentation is to go five days, there would be two turns of the pile. 

    Basket fermentation is commonly practiced in SE Asia and in Central America. Here the fresh beans are placed into a straw or wooden basket where the beans will ferment. The basket permits fluids from the pulp, sometimes called sweatings, to drain away. Beans will be periodically turned by hand or with a spoon until the fermentation is complete.

    Box fermentation is a method which is used where larger numbers of pods are available, usually on large farms, in a village where pods will be brought to the central square for processing or at farmer cooperatives where 10 to 1,000 farmer members might construct a central fermentary. Pods or beans are brought to the central location by hauling in bags, on hand trucks, by mule or by motor bike. As much as one ton of fresh cocoa beans are placed into large boxes, typically constructed in three tiers with the top-most box receiving the fresh beans. When fermentation is established and the fermentation needs turning, beans are unloaded from the top box and moved to the second box with the assistance of gravity. This process is repeated until the fermentation is complete.

Drying. Freshly fermented cocoa beans contain about 40% moisture and must be dried to 8% or less before they can be stored or sold. Drying is a critical step. If the beans are dried too fast they can be acidic and overly sour. If they are dried too slowly, musty off-flavors can appear and degradation of the cocoa can occur. There are basically two types of drying widely used in the cocoa growing areas: sun drying and oven drying. 

    Sun or solar drying systems are widely used because they are cheap and easy to operate. Fermented beans can be simply laid out in a single layer on racks, tarps, mats or on concrete pads and allowed to dry in the sun. When rain does come, beans must be immediately covered to prevent wetting. At night the beans are raked into a pile and typically covered to protect from dew. Solar drying will reduce moisture of cocoa beans to less than 8% in about seven days. In Central and South America, drying pads are often typically covered during rain and at night by a movable roof. 

    Oven drying is also used to dry cocoa. Here a fire is created with wood, oil or another fuel. The fire is separated from the beans by a heat exchanger, so that the fire and smoke do not touch the beans. There are a myriad of ways in which this type of drying can be accomplished. Oven drying obviously consumes fuel and requires an investment in equipment and maintenance. If there is a leak in the heat exchanger, smoke can contaminate the beans, imparting an objectionable, smoky or even a hammy flavor to the beans. But oven drying is often used in regions of the world where the cocoa harvest and the rainy seasons coincide, making sun drying difficult.

Bagging, transportation, local supply chain. Once fermented beans are dried to 8% moisture or less, beans are graded, non-bean material removed and the beans placed into bags. At the farm, recycled bags are used for local sale and for transport to the nearest port. At the port, beans are then subjected to further grading, cleaning, and sorting before being placed into new export bags. Increasingly, the use of bags for export has been replaced by shipping containers in which up to 40,000 lb (18,000 kg) of beans can be shipped.

References

1. Young, A. M. The Chocolate Tree: A Natural History of Cacao. pg. 92, 93, 219. University Press of Florida, Gainsville, FL. 2007. 
2. Cuatrecasas, J. Cacao and its Allies: A Taxonomic Revision of the Genus Theobroma. Bull. U.S. National Museum 35 (3): 379-614, 1964.
3. Ogata, N., Gomez-Pompa, A., Taube, K.A. The Domestication and Distribution of Theobroma Cacao L. in the Neotropics. pg 69-89. In Chocolate in Mesoamerica: A Cultural History of Cacao. McNeil, C. L. (ed): University Press Florida; Gainesville, FL, 2006. 
4. Powis, T.G., Hurst, W.J., Rodriguez, M-C., Ortiz, P., Blake, M., Cheetham, D., Coe, M.D., Hodgson, J.G. Oldest Chocolate in the New World. Antiquity 81 (314): 302-5, 2007.