Anaerobic means "without oxygen". What makes this process different is that coffee cherries are fermented in sealed containers where oxygen is almost entirely absent. This process is interchangeably used with Carbonic Maceration, however the anaerobic process doesn't mandate a CO2-rich environment.
• Initial selection: defective and underripe cherries are removed, often using a flotation method.
• Depulping: depending on the desired outcome, cherries can either be depulped to remove the skin and some mucilage or left whole. The chosen method will influence the flavor profiles of the finished coffee.
• Sealed fermentation: the cherries (either whole or depulped) are then transferred to sealed tanks. These tanks are nearly devoid of oxygen, creating the anaerobic environment.
• Pressure Management: coffee cherries naturally off-gas during fermentation, so tanks are fitted with one-way valves that allow CO2 to escape while preventing oxygen from entering.
• Washing: after fermentation, the coffee beans are thoroughly washed to remove any remaining mucilage.
• Drying: the beans are spread out to dry. This can be done on raised beds, patios, or other surfaces to ensure even drying.
These coffees produce interesting and distinct flavors in the cup. The end results vary drastically, as is the nature of most experimental processed coffees, however anaerobic coffees tend to be a bit creamier thanks to lactic acid buildup in the fermentation process.