What is Anaerobic Fermentation in Coffee?

And how our Cinnamon Pink Bourbon was processed.

Our Limited Release Cinnamon Pink Bourbon is now available!

In this coffee we taste golden raisins, with cinnamon sugar sweetness, and a long finish with cacao nibs and cinnamon. Our staff has been debating whether we think this adds up to a cinnamon raisin bagel, or a cinnamon raisin English muffin - give it a sip and let us know what you think!

Although some degree of fermentation is a part of almost all coffee processing methods - anaerobic fermentation in coffee processing is a relatively new addition, especially in terms of popularity in the coffee world. Fermentation in coffee generally occurs while the coffee is drying after being harvested, in open air and exposed to native yeast and bacteria strains, or after being washed and submerged in water. For anaerobic fermentation in coffee, the coffee cherries or seeds are put into sealed containers so no oxygen is allowed in, resulting in a low to no oxygen environment. During this fermentation, additional yeast and bacteria strains can be added to the container in a controlled manner, specifically those that thrive in low oxygen environments.

So why bother anaerobically fermenting coffee? For all of the endless possibilities and delicious flavors of course! There are so many areas for experimentation and variables that can be modified by the producers during an anaerobic fermentation. Time, temperature, pressure, yeast, or even other fruits, acids, or spices (hint, hint ;)). Anaerobically fermented coffees usually have lots of fruit and wine-like sweetness with a creamy body - though - anaerobic fermentation is much more a modifier than a full on processing method, so it is a bit difficult to generalize how they will taste.

So what’s the deal with the Cinnamon Pink Bourbon coffee we’re roasting?

This coffee underwent a dry anaerobic fermentation for 72 hours - during that time cinnamon sticks and tartaric acid were added, resulting in an infused coffee. After the 72 hours, the coffee cherries are then de-pulped, and left to dry on raised beds until an ideal moisture content is achieved.

Breaking this down a bit - dry means that there was no liquid added during the fermentation. This is slightly confusing since naturally processed coffees are sometimes called “dry process”, but that isn’t the case here. Tartaric acid is most notably found in grapes and a byproduct of fermenting wine - it is also commonly used as an additive to provide an extra tanginess. Importantly, the coffee is de-pulped - the coffee seed is separated from the fruit - before drying. Because the seed is stripped from the fruit but not washed, this means the drying method is considered a honey process. The coffee is then allowed to dry on those raised beds, allowing for proper air circulation. Once it is dried fully, the coffee is bagged, and eventually arrives at our door. The final step for us is to roast, taste, and pack the coffee for folks like you to sip and enjoy!

This is a coffee where you can really taste the effort, care, and creativity that went into it. It’s surprisingly clean for a heavily processed coffee, with pleasant and clean dried fruit acidity like raisins, a sugary sweetness, cacao nibs, and of course a cinnamon note that carries this coffee to the next level.

Have you had a chance to try this crazy coffee? We have it available in 75g and 4oz bags in our cafes, as well as on our pourover menu at the Strip. Or, grab a bag on our web shop and get it shipped straight to your door!