What are anaerobic and experimental coffees?
5 min read
Anaerobic coffees are fermented in sealed tanks with little or no oxygen, which pushes flavours like wine, tropical fruit and cinnamon. Experimental is a catch-all for newer methods such as yeast inoculation, co-fermenting with fruit or spice, and ageing green beans in barrels. Expect intense, unusual cups and brew them a little gentler.
Why seal the tank?
In normal processing, fermentation happens in open air or open water. In an anaerobic tank, oxygen is pushed out and pressure builds. Different microbes take over and work more slowly. The result is a coffee with loud, layered fruit and often a boozy finish.
The main styles you'll see
| Style | What the producer does | What you taste |
|---|---|---|
| Anaerobic natural | Whole cherries sealed in tanks, then dried whole | Jam, wine, tropical fruit, heavy body |
| Anaerobic washed | Pulped beans sealed with mucilage, then washed | Clean but intense fruit, candy-like |
| Carbonic maceration | Whole cherries in a CO2-filled tank | Bright, winey, sparkling fruit |
| Yeast inoculated | A chosen yeast strain added to the ferment | More predictable fruit or floral notes |
| Co-fermented | Fruit, spice or other ingredients added to the tank | Flavours of the added ingredient, sometimes strong |
| Barrel-aged | Green beans rested in used wine or spirit barrels | Whisky, rum, oak, vanilla |
Indian estates took to these methods quickly in the late 2010s, and several now run small experimental lots every harvest alongside their regular washed and natural coffees.
Are they 'real' coffee flavours?
Anaerobic and carbonic flavours come from the coffee and its own fermentation. Co-fermented and barrel-aged coffees borrow flavour from outside. Neither is wrong, but it helps to know which you are buying. Good roasters say plainly what went into the tank.
How to brew them
- Pour-over or AeroPress show the layers best.
- Start about 2 °C cooler than you would for a washed coffee.
- Grind a touch coarser: these beans extract fast.
- Let them rest a little longer after roasting, around two weeks, for the fruit to settle.
Tip: If you are new to experimental lots, buy a 100 g bag first. Some people love the intensity, some find it too much.
Experimental lots in stock
See all →
Double Fermentation Green Coffee Beans
Ammikulavi Estate – 72-96Hrs Anaerobic Natural Canephora
Anaerobic Arabica Naturals
Kerehaklu Estate - Blossom Culture Washed - Chikmagalur - Light Roast
Compare: Anaerobic vs Natural →
Questions
Is anaerobic coffee stronger?
It is stronger in flavour, not caffeine. Caffeine depends on species and how much you brew.
Is co-fermented coffee flavoured coffee?
Sort of. Flavour from an added ingredient ends up in the bean during fermentation, rather than being sprayed on after roasting. Good roasters label it clearly.
Why do these coffees cost more?
Small batches, careful monitoring and the real risk of losing a batch all add cost.
Read next
What is carbonic maceration coffee?
A winemaking trick applied to coffee cherries. How it works and why it tastes so bright and fruity.
How does fermentation shape coffee flavour?
Every coffee ferments on the way from cherry to bean. Here is what that means and which flavours it creates.
How does processing change the flavour of coffee?
Washed, natural, honey, anaerobic, monsooned. What each method does to the bean and what it tastes like in the cup.
How to pour over Indian naturals and anaerobics
Naturals and anaerobics extract fast and can choke a paper filter. A coarser grind, slightly cooler water and gentler pours keep the fruit clean.