Coffee Processing Method
Anaerobic Fermentation
Anaerobic fermentation places cherries or pulped coffee in sealed, oxygen-free tanks — usually stainless steel with one-way valves — where a different microbial community dominates than in open tanks. The controlled environment produces distinctive cup characters: cinnamon, boozy fruit, cola, and intense sweetness that standard processing cannot replicate.
Because temperature, time, pH, and Brix can be logged throughout, anaerobic fermentation is as much process engineering as tradition. Serious producers track every batch, which suits buyers who want experimental profiles with repeatability instead of one-off ferments that cannot be reproduced next season.
How the anaerobic fermentation works
- Ripe cherry (whole or pulped) loaded into sealed tanks
- CO₂ displaces oxygen; one-way valve vents pressure
- Fermentation 24–120 hours with temperature/pH monitoring
- Coffee removed and dried as natural, honey, or washed
- Slow drying to lock in developed compounds
Anaerobic Fermentation at a glance
| Flavor impact | Amplified sweetness and exotic notes — cinnamon, red wine, tropical punch; can double a lot's cupping-note intensity. |
|---|---|
| Key risks | Over-fermentation producing solvent-like taints; inconsistency without measurement discipline. |
| Water use | Low to moderate, depending on the finishing method chosen. |
| Drying time | Follows the finishing style: 10–25 days. |
Origins known for anaerobic fermentation
Anaerobic Fermentation — frequently asked questions
Is anaerobic coffee safe and stable to import?
Yes, when properly finished and dried to standard moisture (10–12%) and water activity (<0.70 aw), anaerobic lots ship like any other specialty coffee. The fermentation happens before drying and doesn't continue in the bag.
Why is anaerobic coffee more expensive?
Tank infrastructure, longer processing time, measurement overhead, and small batch sizes all add cost — plus demand from roasters seeking distinctive profiles currently outstrips supply.
What's the difference between anaerobic and carbonic maceration?
Carbonic maceration is a specific anaerobic technique borrowed from winemaking where whole cherries ferment in a CO₂-flushed environment intracellularly. All carbonic maceration is anaerobic, but not all anaerobic lots use whole-cherry carbonic technique.
Volcana Coffee produces washed, natural, and honey-processed lots on the Bolaven Plateau, Laos, with controlled fermentation and SGS-verified quality. Ask for our current processing menu and cupping samples.
Request a SampleOther processing methods
Washed Process
Clean, articulate cups with bright acidity and clear varietal character.
Natural Process
Heavy body, intense berry and tropical fruit, lower perceived acidity, wine-like sweetness. Signature profile of Ethiopian and Brazilian naturals..
Honey Process
Rounder body and more sweetness than washed, cleaner than natural.
Carbonic Maceration
Winey, jammy fruit, banana and bubble-gum esters, silky body.