Fermentation tank

To begin the fermentation proces, the de-pulped coffee beans are deposited into large, clean tanks.  The coffee beans ferment in the mucilage that is left on the bean after the de-pulping process, transforming the natural sugars to liquid.

Fermentation can take from 4 hours to 3 days depending on the country, altitude and humidity of a particular area.  It is especially important that the tanks are cleaned out after each use to avoid bacterial build up which can affect the flavor of the next batch of fermenting coffee.

In one common method used to determine if the fermentation process is complete, a clean stick is submerged into the fermentation tank, then pulled out. If the circle created by the stick remains, the sugars have not dissolved enough, and the coffee is not ready to be washed to end the fermentation process. If the coffee beans easily flow back together, fermentation is complete and the beans are ready to be washed.