Anaerobic processing is a relatively new and innovative method of processing coffee. In this process, coffee beans are fermented in an environment where air is removed, creating an anaerobic environment.
This fermentation process can take anywhere from 12 to 72 hours and can have a major impact on the taste of the coffee. For example, anaerobic processing can add notes of tropical fruit, chocolate and caramel to coffee.
The anaerobic processing method is still in the experimental phase and is not widely used. While it can provide a unique and interesting tasting coffee, it can be expensive and logistically difficult to achieve. For this reason, anaerobic processing remains a rarely used process in the specialty coffee industry.