During the 2015 world barista championship, Sasa Sestic introduced anaerobic coffee and forever changed the world of specialty coffee. Now-a-days, the term Anaerobic coffee gets thrown around a lot, but what does it really mean? Is it actually better than traditionally processed coffees or is everyone just being a snob?
What is Anaerobic coffee
To put it simply when the coffee is kept in an enclosed space, fermentation slows down due to the limited oxygen supply. How does this affect the coffee’s taste? Well, limiting the oxygen supply, means that the microorganisms have to feed on the sugars more slowly. This allows the producer to stretch out the fermentation time and give the microorganisms and wild yeasts present in the cherries and mucilage more time to break down the coffee proteins, develop slowly, which gives the coffee unique flavours.
Anaerobic vs Traditional Processing
There are two ways to conduct anaerobic fermentation – sealing the coffee in plastic bags which is usually used for cherries or in large steel drums - this can be done for both cherries and the beans with the mucilage. Often kept from 48 to 72 hours, this process is done as an extra step in what are otherwise traditional coffee processing methods – washed, natural and honey. With Anaerobic fermentation these coffees are then classified as anaerobic natural, anaerobic honey and anaerobic washed.
Anaerobic Natural – Like the traditional way, in natural process the whole cherry is kept for fermentation. Unlike natural process the cherries will be kept in metal tanks where the oxygen is taken out. After which they are removed, rinsed, and then dried, typically in the sun, on raised beds or patios, to reduce moisture content. Our Uganda Solara and Brazil Midnight Bloom are good examples of this process. This is not to be confused with Natural Extended where the beans go through natural processing but are left out for longer.
Anaerobic Honey – Like normal honey processing, the beans are fermented along with the mucilage. The amount of mucilage and fermentation time determines the colour – red, yellow and black. Anaerobic takes things a step further by having the fermentation take place in sealed tanks, after which they will be dried on raised beds to bring down moisture content. This process accentuates the fruity and fresh notes of the coffee beans like in our Costa Rica Forbidden Fruit and Uganda Flora.
Anaerobic Washed – Just like in the traditional washed processing method, the coffees are depulped, removing everything and leaving just the bean. What makes the anaerobic washed unique is that the beans are placed in sealed tanks with limited oxygen for a few days before they are taken out to be washed and dried. Washed coffees are known for their clean mouthfeel, like our Colombia Palmera and Uganda Terra. This combined with anaerobic’s funky taste make an exciting combination.
What makes anaerobic coffee so special?
Anaerobic fermentation processes are where the supply of oxygen is limited or even eliminated altogether. This can allow for more complex flavours to be developed. The process brings out unique flavours that you won’t find in traditionally processed coffees. It exaggerates the fruit notes within the coffee giving it subtle fermented and funky characteristics. The anaerobic process has a tendency to impart really strong, bold and intense flavours to the coffees, which combined with the tastes that the traditional coffee processes are known for, makes for a truly exciting brew.
For producers, they get to experiment with the variables such as the duration of fermentation, temperature and the level of oxygen the beans will be exposed to in the tank. This means they can create new flavour profiles that will increase the value of their coffees.
For roasters, they make or break the flavours of these coffees during roasting. Roasters are encouraged to take a more delicate approach so as to preserve the coffees unique flavour profiles. This is because the flavour compounds that give anaerobic coffee their fruity and funky taste can be easily damaged by the excessive heat making the coffee taste burnt.
For coffee bean seller’s and café’s, anaerobic coffee can provide new flavour profiles to their customers. Taste notes of fruits, hints of chocolate and a wine-like complexity. This creates traffic to the café as it grows in popularity for its variety of flavours.
For coffee lovers, there are many benefits both taste and health wise. These coffees have reduced acidity, making it a great option for coffee lovers with sensitive stomachs. The fermentation unlocks even more of the antioxidant packed in coffee beans, helping you get the most out of your coffee. Due to the fermentation process anaerobic beans usually have a longer shelf life than traditionally processed beans.
In conclusion
Of course, like all coffee movements, Anaerobic processing has helped many in the coffee industry to increase the value of their coffees. Patrons are willing to pay more for them, giving producers more capital to re-invest. Developments in technology, especially those borrowed from winemaking, which is where we got anaerobic processing from, has made experimentation with the process easier.
But, like any experimental coffee, the question of transparency and ethics of producing coffee comes into play.
Making anaerobic coffee is expensive, equipment wise, and the coffee should be strictly monitored during production to ensure there is no uncontrolled fermentation which can lead to chemically and mouldy flavours. But it also means they have more control over the final outcome and flavours of the beans. While roasting, due to the delicate composition of the anaerobic flavours, the roasting process including temperature
Yet many see the anaerobic process as a mini revolution in coffee and a gateway to new techniques in coffee processing.
