Anaerobic
Anaerobic fermentation occurs in sealed oxygen-free environments, producing distinctive tropical fruit and winey flavors, one of the most talked-about methods in specialty coffee.
What is Anaerobic Fermentation?
Anaerobic fermentation places coffee beans in sealed containers with oxygen removed. In this oxygen-free environment, specific lactic acid bacteria and yeasts drive fermentation, producing flavor compounds that differ dramatically from conventional aerobic fermentation.
Processing Steps
- Harvest: carefully select fully ripe coffee cherries
- Loading: place the beans (with or without pulp) into sealed stainless steel or plastic tanks
- Degassing: install a one-way valve to release CO₂ while preventing oxygen entry
- Temperature-controlled fermentation: ferment at 15–22°C for 48–96 hours
- Monitoring: continuously measure pH and temperature to ensure quality
- Post-processing: after fermentation, choose washed or natural drying
Flavor Profile
Anaerobic fermentation produces highly distinctive flavors:
- Tropical fruit bomb: intense passion fruit, lychee, and mango
- Winey: noticeable red wine and whiskey-like fermented character
- Syrupy texture: extremely rich sweetness and viscosity
- Unique fermented notes: cinnamon and clove spice tones
- Long finish: flavor lingers in the mouth for an extended time
Representative Origins
- Colombia (a leader in anaerobic technique)
- Costa Rica
- Ethiopia
- Panama