Giling Basah is a term used by Indonesian coffee processors to describe the method they use to remove the hulls of Coffea arabica. Literally translated from Indonesian, the term means "wet grinding". Confusingly, the Arabica coffee industry also uses the terms "wet hulled", "semi washed" and "semi dried" to describe the same process.
Most small-scale farmers in Sumatra, Sulawesi, Flores and Papua use Giling Basah. The mature coffee bean, referred to as green coffee bean, is first harvested. In the Giling Basah processing method, farmers remove the outer skin from the cherries mechanically, using locally built pulping machines, called “luwak”. The coffee beans, still coated with mucilage, are then stored for up to a day. Afterwards the mucilage is washed off and the parchment coffee is partially dried for sale, retaining only 30% to 35% of the moisture content.
Processors and collectors then hull the coffee in a semi-wet state, which gives the beans a unique bluish-green appearance. This method is thought to reduce acidity and increase body, resulting in the classic Indonesian cup profile.
The Giling Basah process can create a "goat's foot," a split on one end, in green coffee beans. Sometimes the hulling machine partially crushes a soft bean, giving the bean a shape resembling a cloven hoof.