Why are washed coffee beans blue-green in color? What varieties of washed coffee beans are recommended?

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Washed Method

The washed method utilizes washing and fermentation to remove the pulp, mucilage, and skin. Farms using this method must construct washing tanks and have access to a continuous supply of fresh water. During processing, the fermented beans are placed in tanks and moved back and forth, using the friction between beans and the power of flowing water to wash the coffee beans until smooth and clean. The entire fermentation process takes approximately 24-30 hours.

After washing, the coffee beans are still encased in their parchment layer with a moisture content of 50%. They must be dried to reduce the moisture content to 12%, otherwise they will continue to ferment and become moldy and spoiled.

The better processing method is sun drying, which takes 1-3 weeks but produces exceptional flavor and is quite popular.

The washed processing method generally removes the silverskin from coffee beans during its processing, giving them a special luster. However, the natural processing method (dry method) only removes the coffee husk, leaving the silverskin completely intact.

Generally, washed green beans are blue-green in color, while natural processed green beans are yellow-green.

Ethiopian Washed Method

This belongs to the traditional wet fermentation processing method. Coffee cherries are washed, peeled, and placed in fermentation tanks with water covering the fruits for wet fermentation. They are then washed, soaked overnight in clean water tanks, and sun-dried on drying racks the next day. The wet fermentation takes 12-30 hours, requires large amounts of clean water, and requires monitoring that the pH does not drop below four or five.

Recommended Washed Coffee Beans: Kenyan Washed

The famous K72 method. Coffee cherries are washed, peeled, and undergo dry fermentation for 24 hours, then washed, followed by another 24-hour dry fermentation, washed again, and then another 24-hour dry fermentation. This cycle is repeated to achieve 72 hours of fermentation, after which they are washed and soaked in water tanks overnight before beginning sun drying the next day.

Through 3 repeated cycles reaching 72 hours, it's called the Kenyan 72-hour fermentation washed processing method, abbreviated as [K72].

Kenyan coffee washing tanks have two levels, high and low. The process is: in the evening, harvested coffee fruits are first sorted to remove defects, then depulped. The sticky parchment beans with most mucilage removed are then placed in the lower clean water pool for secondary fermentation. The circulating water is renewed every few hours to prevent mold growth. They are then channeled to washing canals to remove residual mucilage.

Such labor-intensive and water-consuming processing explains why Kenyan coffee has such refined and delicate flavors.

Recommended Washed Coffee Beans: Guatemala

Guatemala's Fraijanes region surrounds the capital Guatemala City, featuring high altitude, abundant rainfall, and significant humidity variations. Volcanic ash from Guatemala's most active volcano, Pacaya, provides important minerals to the region's soil. The green beans have grassy and spicy flavors, with a distinctive smoky taste and strong aroma.

The harvested berries have most of their pulp separated from the coffee beans using a depulping machine. The parchment beans are then guided to a clean water tank and soaked in water for fermentation to completely remove residual pulp layers. Through water processing, unripe and defective beans are selected out due to buoyancy, and the fermentation process is better controlled. Therefore, unlike natural processed beans that may have impure flavors, washed beans present distinct fruit acidity, slightly stronger complexity, and cleaner cup characteristics (without any negative flavors like astringency or sharpness).

Recommended Washed Coffee Beans: Papua New Guinea

Due to its geographical location in the southern hemisphere, the local coffee harvesting season is approximately from May to August (most of Central and South America harvests from October to February of the following year). Farms and surrounding small farmers harvest mature red coffee cherries on nearly 413 hectares of vast land, then send them to their own processing facilities for post-processing. However, Papua New Guinea's local washed processing differs from Central and South American processing methods.

It uses three washing fermentations, each soaking for about 12 hours, with clean water replaced to control coffee flavor. After washing, the green beans have their outer husks removed and then undergo various grading, such as AA, AB, PB (peaberries), etc. This meticulous post-processing method brings bright and delicate fruit acidity to the coffee itself, with a clean and lingering sweet taste.

Papua New Guinea is located on the island of Guinea. Although geographically close to Indonesia, its coffee flavor is completely different from the full-bodied richness of Mandheling. Papua New Guinea beans have a clean taste, full of floral aroma and sweet aftertaste.

FrontStreet Coffee: A roastery in Guangzhou with a small shop but diverse bean varieties, where you can find various famous and lesser-known beans. They also provide online shop services. https://shop104210103.taobao.com

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