Let’s Talk About The Anaerobic Process
Our selection of the new Costa Rican crop is about to be finalized and we are already very excited to receive our new coffees. Most of the coffees we have been selecting are naturals or honey process but some lots are also anaerobic. We thought that it could be interesting to explain a bit more what this special process consisted of.
The Basics of Anaerobic:
- The coffee bean is a fruit and the mucilage is its juice.
- The flavor of the fruit is concentrated in the juice and not in the beans.
- The coffee mucilage has different levels of sugars according to the maturity of the coffee, variety, time of the year, type of soil. The mucilage has also diverse flavors.
- Nearly all coffee undergoes some fermentation of its fruit material, from natural to non-mechanically washed lots.
- Fermentation is when yeast and bacteria begin converting the sugars and acids in the coffee’s mucilage, generating different organic acids, carbon dioxide, ethyl alcohol and other compounds in the process.
- During alcoholic fermentation CO2 is produced, which, in a closed environment, produces a lot of pressure.
- By controlling the temperature one can make the alcoholic fermentation shorter or longer.
Anaerobic Coffee, Step by Step:
First, the cherries are harvested when they are very matured (with a Britx degree measurement of its mucilage that is close to 26). Cherries are then pulped and placed in a stainless-steel tank with all their mucilage. The main thing that differentiates anaerobic coffee fermentation from carbonic maceration of coffee is that in carbonic maceration the cherry is left intact, and not pulped prior to entering a sealed tank. Some producers keep apart some cherries to be pulped. The parchment of those cherries is passed through the pulping machine and well pressed to obtain the gel of the mucilage. This gel is then added inside the fermentation tank with the initial pulped cherries.
The tank is hermetically closed and the fermentation process will undergo for several hours depending on the environment. Temperature is controlled all the time during the process. The production of C02 during the fermentation process and the pressure resulting from it will allows the flavors of the coffee juices to be introduced into the parchment. That is the key point of this process. Fermentation must be stopped when the sugars in the mucilage have been consumed. Drying process must follow quickly to stop the fermentation process and avoid altering the flavors.
Anaerobic coffees offer a good alternative to producers to “boost” the profile of their coffees helping them to compete on the market against varieties with better genetics. For the final consumes, those coffees are offering an unique experience with very expressive and identifiable flavor notes like gingerbread, cinnamon, licorice or bubble gum. However, one has to keep in mind that those processes are difficult to control, as they require expertise, extra work and time to achieve good results.
We also noticed that producers this year were more reluctant to use this process due to its uncertainty on the market. Purchase price must also reflect the additional efforts in time, space and labor.
Stay tuned to receive the first sample of these amazing coffees!
