Anaerobic coffee is fermenting coffee in an environment that lacks oxygen. It’s not a new way of processing, you still need to do the usual steps, but it’s way of introducing new flavours to coffee, and importantly of making an effective recipe for producing those flavours.
All coffee goes through some fermentation, albeit in an oxygen-rich environment as they are laid out on beds. This fermentation process helps to develop the flavour which that coffee is known for. The way that fermentation is controlled influences the final flavour notes.
As producers consider the effect of fermentation more and more on the quality and profile of their coffee, they are adopting different and interesting techniques to diversify their offerings.
One method that’s becoming more popular is fermenting coffee in a controlled anaerobic environment, meaning that the coffee is held in a vessel without the presence of oxygen.
The fermentation process itself is already anaerobic, meaning that the yeast and bacteria which do the work of fermenting a coffee cherry’s sugar content do not need oxygen to successfully transform the organic material. (This is why it’s the environment that’s anaerobic in these cases.)
One of the main benefits of holding the coffee in an oxygen-depleted environment, then, is to slow the fermentation process, which allows a totally different spectrum of flavours to evolve.
In a Washed process the controlled fermentation might last 12–24 hours on average, whereas anaerobic environment fermentation can take 96 hours or longer, depending on the thermal retention inside the tank.
Different fermentation-tank materials will have different thermal retention, and producers choose depending on the desired outcome they’re looking for. Stainless steel is one material commonly chosen, as is a thick plastic.
The tanks contain a one-way valve that allows the producer to do a controlled release of oxygen from the vessel as well as the CO2 created during the fermentation process; careful monitoring of the coffee fruits pH as well as the temperature inside the tank is pivotal to ensuring the success of the process. Sometimes additives are introduced at this stage to create additional flavour.
This raises an important question of whether this manipulation of flavours comes at the expense of the technical expertise of the producer and terroir. Beans that have existing intricate flavour profiles can be modified through the fermentation process. While we might welcome the additional spectrum of tasting notes, and the ability to potentially extract these in a repeatable and consistent fashion – making it appealing to brands wishing to establish a recognisable flavour, there is a question of what this might mean to the crafting of more ‘natural’ flavours derived from the organic materials.
After fermentation, the coffee’s processing can be completed in any number of ways: The fruit can be fully removed as in a Washed process, the pulp can be removed but the mucilage left on as in a Honey process, or the cherries can be dried whole as in a Natural. The length of drying time will vary based on this last step as well as the environment around the drying area.
Due to the way in which anaerobic coffee is made, it has a different flavour profile from your standard coffee.
The result is a coffee bean that has a far fruitier taste than you would normally get from coffee. In fact, anaerobic coffee can have a variety of different flavors depending on the additives that have been put into the mix, as well as the base starting bean.
Most anaerobic coffee tastes a bit creamier than your typical coffee. It will also have lost a little bit of the bitterness. Not so much that it doesn’t taste like coffee, but the sweeter, fruitier flavors are going to be a lot more prominent. Some people have likened the taste to pineapples, cherries, and maybe even a touch of lemon. It is all about how the producer works to ferment that coffee.
Où trouver du café seché sous mode anaérobie?