There are two main post-harvest processes done on cacao farms: fermentation and drying. After cacao is harvested, the pods are taken to a central area to be fermented. This must begin quickly, as the seeds immediately begin to germinate once they’re cut off from the tree. In the fermentation area, pods are cracked open and their seeds removed. The hard shell & soft spine holding the seeds in place is discarded and often turned into compost for the farm.
The pulp-coated seeds are placed into a fermentation box, traditionally lined with banana leaves. They’re left to ferment for 3-7 days depending on cacao type. The seeds are often called cacao beans at this stage, and some farmers sort cacao beans by size or pod color before fermenting. During fermentation, the sugars in the pulp surrounding the seeds are consumed by local yeast and bacteria, changing the composition of the beans.
Temperatures inside fermentation boxes can reach 50 degrees Celsius; any higher and it can damage the beans, but any lower and fermentation won’t complete. Fermentation is crucial to chocolate making, as it’s the point at which beans develop the flavor precursors typically associated with cocoa. These flavors are enhanced during roasting, but fermentation lays the foundation. Beans are usually turned multiple times during fermentation, to ensure that all cacao is equally fermented, and the temperature doesn’t rise too high too quickly.
On the other hand, some farmers don’t ferment their beans at all, choosing to immediately dry them in the sun. This is a problem because of fermentation’s crucial role in flavor development. Those unfermented beans will lack a complex and chocolatey flavor at later steps of chocolate making, as well as often being overly bitter and astringent.
Drying is the next step in cocoa processing after harvest. Once farmers have tested beans from all parts of the batch and ensured that they’re properly fermented, the beans are poured onto tarps to be dried. The beans must be spread in very thin layers, ideally in the sun, to ensure that fermentation stops immediately. If beans stay in clumps, they may continue to ferment in the sun, ruining the flavor.
Cacao dries in the sun for several days, pulled under shelter during rain storms and other adverse weather. If cacao dries too quickly, then it may develop a sour flavor due to trapped acids which would have otherwise escaped during the drying process. But if cacao dries too slowly then it may become moldy or begin to develop other off flavors. Once the moisture level of the beans hovers around 7%, the beans are put into bags and prepared for either storage or shipment.
After post-harvest processing, cocoa will most likely either be processed into cocoa butter & cocoa powder, or become chocolate.