Anaerobic (oxygen-free) fermentation is a new method whereby the coffee is processed in a fully sealed and oxygen deprived fermentation tank.

First, the coffee is de-pulped and separated from its mucilage. Then, the seeds are added to a ferment tank and covered with their own tightly-packed mucilage gel. After around 18-24 hours, the anaerobic process has caused a breakdown in the mucilage and a huge buildup of CO2 pressure in the tank. This pressure forces the flavours of the juicy mucilage into the coffee parchment. Once carefully removed from the tank, the coffee is dried to ensuring a halting of the fermentation stage.

This experimental process yields unexpected and complex flavours, while also giving the producer great control over the sugars, temperature, pressure, pH and length of the ferment.