Anaerobic fermentation is a coffee processing method where coffee is fermented in pressurized sealed tanks deprived of oxygen. This lack of oxygen produces distinct acids, lactic acids for example, that create a different and distinct flavor profile for the coffee. This process can be done with the coffee still in cherry or with coffee that has been de-dulped in the mucilage. The coffee is then dried either in cherry (natural process), in mucilage (honey process), or after it has been washed (washed process.)