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What is the difference between wet-hulled and semi-natural processed coffee beans? What are the characteristics of wet-hulled processed coffee beans?

Published: 2026-01-27 Author: FrontStreet Coffee

Last Updated: 2026/01/27, Wet-hulled processing is a coffee processing method from Indonesia. Here's the specific process of wet-hulling: Farmers first harvest ripe coffee cherries and place them in water tanks to use flotation to remove debris and unripe coffee cherries. Then a depulper is used to remove the pulp and skin, preserving the parchment and mucilage before the beans undergo a relatively short fermentation period. Unlike fully washed processing, the parchment-covered beans are then sold to collectors while still having high moisture content (around 30-50%). These collectors quickly hull the beans while they're still moist, hence the name "wet-hulled." This unique processing method results in coffee beans with distinctive earthy, spicy, and sometimes woody flavors with lower acidity and a fuller body compared to other processing methods.

Wet Hulling Processing Method

Wet hulling is a coffee processing method from Indonesia. Here's the specific process: Coffee farmers first pick ripe coffee cherries and place them in a water tank to use flotation to remove debris and unripe cherries. Then they use a depulper to remove the pulp and skin, keeping the parchment and mucilage, followed by a brief fermentation to decompose the mucilage. The washed green coffee beans undergo sun-drying until their moisture content drops to 20%-24%. Then machines are used to remove the parchment, and the hulled coffee beans undergo another drying until their moisture content reaches about 12-13%, completing the process.

Wet hulling process at Indonesian coffee farm

Pulped Natural Processing Method

The pulped natural processing method is commonly used in Brazil:

First, coffee cherries are placed in large water tanks, where floating cherries are removed. The sinking cherries are then put through a depulper to remove the pulp. This process better eliminates unripe cherries and, more importantly, allows the coffee beans to sun-dry without pulp, just coated with mucilage, which helps control the subsequent fermentation process.
After removing the skin and pulp, yellow mucilage becomes visible. The coffee cherries with mucilage are then sun-dried (After coffee beans have their pulp removed, they are coated with a sticky gelatinous substance called mucilage).
Dry until the bean's moisture content reaches between 10.5%-12% before hulling.
Finally, before the beans are bagged for export, they undergo a polishing process.

Pulped natural coffee beans drying on patios

Horsehoof Beans from Indonesian Wet Hulling

The wet hulling process creates "defects" in coffee beans because when the parchment is removed during wet hulling, the coffee still has a high moisture content of 20-24%. In contrast, in most other processing methods, coffee is hulled only when its moisture content drops to 10-12%. In this "semi-dry" state, the parchment tends to adhere to the surface of the green beans, making dehulling more difficult than with "fully dry" beans and requiring greater friction during the process.

However, on the other hand, "semi-dry" green coffee beans are extremely fragile at this stage, with hardness far below that of "fully dry" beans. Therefore, the beans are more easily crushed and form small chips. This explains why coffee enthusiasts notice that when they examine Mandheling coffee beans at FrontStreet Coffee, they find beans shaped like horse hooves or sheep hooves, which is one of the distinctive characteristics of Mandheling coffee beans.