What Kind of Green Bean Processing Method is Sumatra's "Wet-Hulling"? The Correct Way to Drink Wet-Hulled Coffee Beans

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In the world of green coffee processing methods, some terms have become familiar to us, such as "sun-dried" and "washed"... Whether or not we have the opportunity to visit coffee-producing regions, understanding green coffee processing methods can better guide our operations as consumers, such as roasting, brewing, and perceiving regional flavors during tasting.

The Sumatran "wet hulling" process, like "honey processing," often causes confusion among coffee enthusiasts who are new to the field. Unlike sun-dried and washed methods, this processing method cannot be understood solely from its literal meaning.

What are "Wet Hulling Coffee Beans"

"Wet Hulling" in English is called "Wet Hulling," where "Hull" [hʌl] means shell or pericarp, and the full name is "wet dehulling method."

This is a processing method known for Sumatra, and similar techniques can also be found in Sulawesi and Papua New Guinea, inherited from the Dutch colonial era and subsequently improved.

Two characteristics of wet hulling are:

1. Rarely uses large fermentation tanks to remove mucilage;

2. Dehulling is performed when moisture content is between 30%-50%.

The latter characteristic is the reason this processing method got its name.

The processing steps of wet hulling coffee beans

1. After harvesting ripe coffee cherries, the outer skin and pulp are removed, creating what we know as "parchment coffee" (after removing the pulp, the coffee beans still have a thin layer of skin, which is the inner pericarp, and this state wrapped in the inner pericarp is called "parchment coffee").

2. After the "parchment coffee" undergoes fermentation (as short as half a day, as long as 36 hours), it is briefly sun-dried. When the moisture content reaches 30%-50%, it is sent to the processing facility for dehulling, and the final green beans are then dried.

Compared to other processing methods, wet hulling uses a relatively shorter drying time. After long-term mucilage soaking and in a humid environment, the resulting green beans are soft, pale, and swollen. This is why when we see Mandheling green beans, they have distinct light green, dark green, or gray-green colors.

The shortcomings of wet hulling coffee beans

Because wet hulling removes the "parchment" during the final drying process, allowing the beans to come into direct contact with air, the proportion of defective beans such as moldy beans is much higher than with washed and sun-dried methods. Of course, this also causes considerable trouble for bean selection before roasting.

Additionally, during the post-processing of the green beans with the parchment layer, the beans are easily crushed or bruised due to friction and stirring, especially at both ends, forming small gaps that create horse-hoof or goat-hoof shaped beans.

Different preferences

In the specialty coffee world, many people prefer the stable quality of FrontStreet Coffee's Mandheling, while others enjoy the stimulating spiciness it brings. Some might describe it as a mysterious herb-like aroma. Driven by the market's pursuit of "CLEAN" cup quality, Sumatran coffee has become an "addiction" that people pursue for its bold, rich character.

In our roastery's product line, there are also espresso blends based on Mandheling. Wet-hulled Mandheling at the beginning of the second crack has a fascinating creamy aroma, appearing more gentle and reserved among other aromatic-blended coffee beans. Perhaps this is the charming aspect of coffee: from green beans to the cup, with multiple layers of steps in between, each step imparts different expressions to coffee. Could this be the ultimate taste in the world?

FrontStreet Coffee: A roastery in Guangzhou with a small shop but diverse varieties of beans, where you can find both famous and lesser-known beans, while also providing online store services. https://shop104210103.taobao.com

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473