Washed Coffee Beans: Classification, Brewing Methods, and Characteristics

Professional Coffee Knowledge Exchange

For more coffee bean information, please follow Coffee Workshop (WeChat official account: cafe_style).

The Wet Processing Method of Coffee Beans

During each coffee harvest season, farmers collect coffee cherries after picking and place them in designated outdoor water tanks. The tanks are filled with water to remove branches, rotten leaves, and perform density screening. Let's examine the process of the wet processing method for coffee beans.

Step-by-Step Process

1. Initial Floating Selection

After harvesting, coffee cherries are poured into water tanks. Unripe and overripe coffee cherries float on the water's surface, while fully ripe cherries sink to the bottom of the tank. This utilizes water's buoyancy for the first natural selection of good quality cherries.

2. Soaking and Hydrolysis

Once cherries enter the water tanks, they begin soaking and hydrolysis. The tanks connect to water channels, and coffee cherries continuously move with the water flow, rubbing against each other, causing the skin and pulp to loosen and separate.

3. Mechanical Depulping

Mechanical methods are used to remove the coffee cherry's skin and pulp, revealing the yellow mucilage of the coffee bean.

4. Fermentation Process

Next, the coffee beans begin fermentation. The duration varies depending on local conditions, as different origins have different weather and climate, resulting in varying fermentation times and effects.

Central and South American countries typically ferment coffee in water-filled tanks for 12-36 hours under microbial action (except for Brazil). Kenya usually allows coffee with mucilage to react naturally with airborne microorganisms to remove the gelatinous layer.

5. Washing

After fermentation is complete, coffee beans with their parchment layer enter washing channels where they undergo extensive water rinsing.

6. Drying Process

After mucilage removal, coffee beans undergo drying treatment through several methods:

1. Direct sunlight drying (fast drying speed, relatively low coffee cherry density);

2. Combination of direct and mechanical drying (for example: sun-drying for 2 days followed by mechanical drying);

3. Shade drying (using natural wind and temperature for drying, relatively long drying time);

4. Combination of shade and sun drying (shade drying first, then sun drying).

Typically, 10 days to one month are needed to achieve moisture content stability, with the intermediate value of stable moisture content being around 12%.

7. Resting Period

Coffee beans with parchment are placed in burlap bags for "resting" for approximately 2-3 months.

8. Final Processing

The parchment is removed from the raw coffee beans, which are then repackaged for export and sale.

Characteristics and Applications of Wet Processing

Wet-processed coffee beans have natural characteristics: transparent green coffee beans, smooth surfaces, clean coffee beans, and bright acidity. Because this method requires large amounts of water, it is suitable for regions with abundant water resources (such as Africa, Central America, South America, Indonesia, and Yunnan).

FrontStreet Coffee: A roastery in Guangzhou with a small storefront but diverse bean varieties, where you can find various famous and lesser-known beans. They also provide online shop services at 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