Wet-hulling, or giling basah, is a traditional coffee processing method used in Indonesia. The word ‘hulling’ refers to removing the parchment from the beans.
Firstly, ripped cherries are picked and depulped through a hand-cranked pulper that only removes the skins while retaining most of the fruit and mucilage on the beans.
The beans will then be placed in a water tank or plastic rice bags overnight to allow the wet-fermentation process to take place. This step breaks down the pectin in the mucilage, making it easier for the mucilage to be washed off the next day.
After removing the mucilage, what remains is also known as a wet parchment coffee. From here, the beans will be sun dried in its parchment for around 24-72 hours, where the moisture content will be about 20-24% — leaving the bean at the required hardness for hulling. Since the parchments are semi-dry, the beans will be soft and inflated with water.
The semi-dried beans will be placed through a specially designed huller that hulls semi-dried parchment. Finally, the process will be finished when the hulled beans are re-dried until it has 10-12% moisture content, before it is prepared for shipping.
Wet-hulled coffee beans are identified by their dark green and bluish appearance. They usually have a heavy body, little acidity or sweetness. Notable cupping notes include herbs and distinct spicy notes.