Dry fermentation ferments pulped coffee without adding water to the tank — the beans sit in their own mucilage.
Versus wet fermentation
Wet fermentation submerges the coffee, which moderates temperature and dilutes the products of fermentation.
Dry fermentation concentrates everything. Microbial activity is more intense, temperature rises faster, and the flavour contribution is greater.
The result
More pronounced fruit and complexity than a wet-fermented washed coffee, while remaining cleaner than a natural.
The risk
Less margin. Without water to buffer it, an unmonitored tank can overheat and over-ferment quickly, producing sour, vinegary coffee.
Producers running dry fermentation successfully monitor temperature closely and stop on measurement rather than on the clock.
Where it is used
Kenya traditionally, and increasingly by quality-focused producers elsewhere experimenting with fermentation as a flavour variable.
Brewing it
Filter, light roast, a clean brewer.