Coffee Fermentation | What is It & What Are the Benefits?

Fermentation isn’t a new idea. We’re familiar with wine, beer, kombucha, and other things that undergo fermentation. Although it's an old process, did you know that some coffees go through fermentation to enhance their flavor? Coffee processing has come a long way. Here at Sagebrush, we love to see the evolution of coffee processing and we love to be a part of it. Not too long ago, I wrote about the Hydro-Honey process, which is a new and innovative way of combining well knows processes together to bring the best out of each into one kind of coffee. We recently launched our Hydro-Honey Guatemala, so now you have the chance to taste coffee processed in a new and innovative way. We are now excited to share for the first time coffee that has gone through the anaerobic fermentation process. You may be asking yourself what the benefits and differences of fermented coffee are. Now you won’t just find out about it, but you can taste it.

Natural fermentation occurs in everyday coffee production. When cherries are left to dry on their own or when mucilage is left on, fermentation occurs. I'm not talking about the regular chemical changes that occur when cherries are left to dry during the dry process or when mucilage is left on the bean in the honey process. I’m talking about the intentional process of encouraging microbial activity in coffee beyond what happens naturally when you let coffee dry. I suppose you can call it passive or active fermentation. Those aren’t official coffee processing terms, I just made them up to distinguish between what happens when you let fermentation naturally happen and intentional fermentation using bags or tanks. One thing to remember is that fermentation doesn’t elevate the quality of the coffee. The quality of the coffee comes from the quality of the soil and the work producers put in to make the quality great. Fermentation is used to draw out more flavor from the coffee bean much like you see in wine and other fermented beverages.

There are two major ways to identify fermentation, aerobic and anaerobic. In aerobic fermentation, oxygen contributes to the growth of microorganisms. It’s pretty much what happens in the usual daily coffee processes. Because there are microorganisms everywhere, simply by leaving the coffee to dry on drying beds, some level of aerobic fermentation will occur. What makes anaerobic fermentation special is that tanks or silage bags are used to intentionally keep oxygen out. Coffee will be allowed to ferment anywhere from 48 hours to 10 days. Some producers choose to add ingredients like local yeasts to encourage microbial activity. This carefully controlled process and environment is what causes a lot of the changes in the flavor. Since the fermentation process can be different for each producer, the flavor may vary widely even within the same region or even the same farm. With this measure of control also comes more labor, more education, and more equipment necessary for workers on farms. 

Our newest fermented coffee offering comes from the Altieri Farm in Panama which is also their newest process. This farm produces award-winning coffee and is now offering a dry-process fermented variety. This Geisha variety comes from a farm that borders the Volcan Baru National Park and sits at an altitude of 1850 meters above sea level. First, the cherry is manually selected to make sure it's mature. Once it's cleaned, the beans are sundried in their greenhouse to achieve maximum sugar concentration. Since it’s a dry process, the cherry is left on during the drying process. The next step is to place the beans in silage bags with wild yeast local to the farm to encourage microbial activity for several days. This is where the fermentation process accelerates. After fermentation is complete cherries are sundried once again until they reach 11% humidity. Once all of this process is complete, the coffee is placed in a controlled temperature warehouse for resting.

That’s the process for our newest variety of Panama Geisha, but even within the Altieri farm, it isn’t their only method of fermentation. They also use fermentation tanks for some of their other varieties of fermented coffee. We will soon feature a coffee from the Altieri farm fermented in tanks. I’m excited to try both to see just how different they are.