Worka Yirgacheffe Anaerobic Natural

Our in-country partner, Tracon Coffee, has been experimenting with new processing methods as a way to increase value and stand out among a growing number of specialty washing stations in Ethiopia. Tracon has been trialing anaerobic fermentation with several of their washing stations in Yirgacheffe  since 2015.

Farming methods in the region remain largely traditional. Yirgacheffe farmers typically intercrop their coffee plants with other food crops. This method is common among smallholders because it maximizes land use and provides food for their families.  

In addition to remaining traditionally intercropped, most farms are also organic-by-default. Farmers in Yirgacheffe typically use very few—if any—fertilizers or pesticides. Most farm work is done manually by the immediate family. 

To capitalize on the magnificent climate, that station provides training to help farmers produce better quality cherry. Training focuses on procedures for harvesting and transporting cherry. 

Farmers selectively handpick ripe cherry and deliver it to Worka. At intake, employees visually inspect cherry and accept only fully ripe cherry for anaerobic fermentation. Selected cherry is tightly packed in GrainPro bags and sealed shut. Cherry ferments anaerobically (without oxygen) for 18 to 24 hours.  

After fermentation, cherry is carefully removed from bags and laid to dry in direct sunlight on raised beds. Workers turn cherry frequently to promote even drying. It takes approximately 2 to 3 weeks for cherry to dry.  

As more producers and washing stations enter specialty coffee, unique processing methods are a new way to stand out among the increasing number of sellers. One of those newer processing methods is anaerobic fermentation. 

Anaerobic fermentation occurs in sealed containers. The seal means the microbes fueling fermentation quickly consume all the oxygen in the container. At that point, the environment becomes anaerobic (without oxygen). In this new environment, the microbes that typically breathe oxygen have a harder time surviving, and those that flourish on carbon dioxide (the typical byproduct of oxygen-breathing microbes) are able to dominate fermentation.  

Microbes are immensely diverse and have the potential to produce a wide array of flavors in coffees. Aerobic (oxygen-breathing) microbes produce different flavor outcomes than anaerobic ones, so we have the potential to produce vastly different flavors simply by changing the available resources for microbes.

Grades in Ethiopia depend on visual inspection for defects and on cup quality. Grade 1 is considered the highest quality coffee. Grade 1 and 2 are considered specialty coffee, grades 3-9 are classified as commercial coffee. Grade 1 is free of cup faults and taints and has zero quakers.