What is Anaerobic Coffee?

Breathing some insight into coffee fermentation and processing...

This week, we’re proud to introduce a new coffee, Ethiopia Gedeb. This Ethiopian coffee is from the Gedeb district of the Yirgacheffe region and is processed at the Worka Sakaro washing station, a co-op of 400+ small coffee growers. Shade-grown at an elevation of 2000+ meters above sea level, there’s something else interesting about this coffee. It’s anaerobically fermented. What do we mean by this? 

Before we go further, it’s important to know that coffee beans are actually the seeds of a fruit. This fruit is often referred to as “coffee cherries.” The cherries must be processed to remove the seeds and there are several different methods to do so. Some producers use a de-pulping machine to clean the fruit skin and mucilage (the fruity pulp) from the coffee seeds. This method is referred to as “washed.” Some producers will allow the coffee to dry on long beds in the sunshine with the fruit skin and pulp intact. This is called “unwashed” or “natural” processing. There is also “honey” processed coffee, where only the outer skin of the fruit is removed, but the mucilage is left as the coffee is then dried.

Anaerobic” means “without oxygen.” Oxygen is taken out of the equation in part of the processing of our Ethiopia Gedeb. It’s a naturally processed anaerobic coffee; this means that the fruit skin and pulp are left intact as the coffee is placed into special barrels. The containers create a sealed, oxygen-deprived environment in which the coffee can macerate and ferment for anywhere from two to ten days. After fermentation, this Ethiopia Gedeb continues processing in the open air and sun until it’s ready to be bagged for exportation.  

So, what is the purpose of depriving the coffee cherries of oxygen? Without air, there is a greater level of control over the fermentation in this method. With control comes consistency. In these conditions, the coffee cherries undergo a metabolic process called glycolysis as energy is synthesized from glucose. This breaks down the mucilage in an extended manner that is easier to manage than traditional methods. 

Slowing down the process allows for a wider array of flavors to develop. Anaerobic coffees are known for their complexity; they develop wine-like flavors and fruity, floral notes. Often, these coffees are described as having a sweet taste and smooth mouthfeel. Anaerobic fermentation also results in a coffee with lower acidity.

When roasting this coffee, we wanted to highlight the wonderful flavors that anaerobic fermenting provides. We chose to roast this coffee lightly, cultivating a juicy mouthfeel and a coffee that boasts notes of sangria and tropical fruit. It’s a limited-release coffee, so make sure to grab one while it’s in stock to try an anaerobically fermented coffee for yourself. We hope it takes your breath away! 

Back to blog