Introduction to Sumatra Coffee Semi-Washed Processing: Why Sumatra Coffee Uses Semi-Washed Method

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Introduction to FrontStreet Coffee's Sumatra Wet Hulling Method

Traditional coffee processing methods are mainly natural and washed. With technological advancements and continuous exploration and experimentation with coffee, honey processing emerged, followed by more complex methods like anaerobic fermentation and wine-like fermentation. However, these have nothing to do with Indonesia. Indonesia has its own unique processing method—the wet hulling method.

Due to its location in the tropical rainforest with abundant rainfall, Indonesia faces insufficient sunny days for coffee processing. As a result, Indonesia has tenaciously developed the world's unique wet hulling processing method, which also gives Indonesian coffee more distinctive flavor characteristics.

Wet Hulling, also known as wet dehulling, is called Giling Basah in the Lombard language. This unique processing method produces dreamlike, jewel-like blue-green raw coffee beans, creating Indonesian coffee that retains only the woody fragrance without grassy smells.

Farmers harvest fully ripe coffee cherries in the morning. After collection, they remove the fruit skin and pulp in the afternoon, keeping the parchment and mucilage. The coffee beans with parchment are then placed in water (usually in large barrels or sinks), and defective beans floating on the surface are skimmed off. (Sumatra's natural environment is superior, and most farmers use mountain spring water.)

The dense beans that sank to the bottom are scooped out, slightly cleaned, and placed in barrels or plastic bags for a brief dry fermentation process, allowing the pectin and sugar on the coffee bean surface to ferment and enhance flavor. The stronger the sour taste, the longer the fermentation time. To fully ferment the pectin and sugars to enhance flavor, generally 12-36 hours of fermentation time is needed, depending on specific conditions.

The parchment-covered coffee beans are naturally dried for 2-3 days until reaching a moisture content of 20-24%. Then a hulling machine removes the parchment to accelerate the drying process, continuing to dry until reaching a moisture content of 12%-13%, completing the work.

The wet hulling method significantly shortens the fermentation period of coffee beans, greatly reducing acidity while making caramel and fruit aromas more pronounced. This is precisely the classic "terroir taste" of Mandheling coffee!

However, this processing method cannot be considered authentic outside of Sumatra Island. The climate of Sumatra Island determines that this wet hulling method is the optimal choice.

Important Notice :

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