The Kopi Arabika Gayo coffee is processed through the wet hulling method. “Wet-hulled” is easily confused with “wet-processed,” another term for “washed,” which is the most common method for processing coffee. But it should not be confused as the two processes produce dramatically different results: wet-hulling emphasizes body and mutes acidity, while wet- processing highlights delicate acidity and sweetness.

Wet-hulling is only practiced in Indonesia, particularly the islands of Sumatra and Sulawesi. The processing consists of the following steps:

1. Harvesting

Harvesting takes place from September until May or June. It is done by the farmers who handpick the red cherries. This way only the more suitable red cherries are selected and represent about 85% of all cherries.

2. Red skin pulping

To make sure that only the best quality beans are used, the harvested beans are peeled the same day they are picked. After getting the red raw beans pulped, the coffee will be immersed in water and then the floating beans are sorted. The process lasts no more than 24 hours.

3. Fermentation

The cherries are fermented overnight to break down the mucilage (the fruit layer beneath the skin), which is then washed off with fresh water.

4. Drying

Drying is done through direct sunlight or using a drying machine or a combination of the two. Drying through direct sunlight is better as the sunlight contains ultraviolet which can result in a better aromatic smell of the beans and allows for longer storage. If sunlight is insufficient, a drying machine shall be used.

Wet-hulled coffee is dried for just a few hours, until it reaches about 50% moisture, at which point the bean is still swollen.

5. Hulling

At this point the coffee needs to be further dried to achieve 25-35% moisture content and is then sent through a wet-huller to remove the parchment layer. Because the bean has not yet dried and shrunk away from the parchment, the friction required at this stage can damage the bean, which is still moist and pliable.

The mill then air-dries the hulled coffee to 12-13% moisture. Without the protective parchment layer the coffee dries quickly, but it’s exposed to wider temperature variation as well as yeast and bacteria from the environment.