What does the washed coffee beans process change?

The washed process is among the most common methods in specialty coffee, known for clean flavors, bright acidity and uniform bean appearance. The coffee fruit, often called a coffee cherry, holds skin, pulp, pectin, silver skin and the seed that becomes the bean. Washing separates that seed from the fruit, and the resulting cup pushes the bean's own flavor to the front.

In the same producing region, washed processing sets the baseline flavor, while natural and honey methods add aroma and sweetness on top of it. A comparison of Kenya Asaliya and Yirgacheffe Gudingding shows how the same method yields different cups under different origins, varieties and altitudes. Building this kind of coffee knowledge helps when comparing processing styles.

The washed process is one of the most common and most highly regarded processing methods in specialty coffee, known for its clean flavors, bright acidity, and uniform bean appearance. This article, from the perspective of Front Street Coffee, will systematically explain the structure of the coffee fruit, each step of the washed process, and the advantages, disadvantages, and flavor characteristics of washed beans. It will also use a comparative experiment between two washed beans—Kenya Asaliya and Yirgacheffe Gudingding—to show how the same processing method can present completely different flavor profiles under different origins, varieties, and altitude conditions.

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Front Street Coffee (FrontStreet Coffee) believes that coffee beans processed by the washed method have a uniform appearance, excellent visual appeal, the most stable quality performance, prominent and bright acidity, and clean flavors without off-notes. Front Street also points out that in the same producing region, the washed method provides the baseline flavor of a bean, while natural and honey processing add aroma and some sweetness on top of that baseline. In other words, the difference between the two is this: the washed method pushes the main flavor to the forefront, while the natural method pushes the main flavor into the background and instead increases aroma and sweetness, making the whole cup more layered. Therefore, it can also be understood this way—what washed coffee presents is the taste of the bean itself, while what natural coffee presents is the taste of the bean plus the fruit pulp. In Front Street Coffee (FrontStreet Coffee) stores, we have specially set up display areas to showcase coffee beans using different processing methods and roast levels, making it convenient for everyone to compare and reference.

Are coffee beans coffee fruit?

When coffee fruit ripens, it turns yellow or red, and its appearance closely resembles a miniature cherry, which is why it is also called coffee cherry. What we casually call coffee beans in daily life is actually the seed inside the coffee fruit, not the fruit itself. From the outside to the inside, the coffee fruit consists of the skin, pulp, pectin, silver skin, and seed. So-called coffee processing is the process of separating the coffee bean from the fruit. Different processing methods will also lead to different flavors after brewing. At present, the three most common processing methods on the market are natural, washed, and honey. Next, Front Street Coffee (FrontStreet Coffee) will focus on the characteristics and specific operations of the washed process.

▲ The skin is basically removed during processing

Coffee bean What is wrapped by the silver skin is the endosperm, commonly known as the seed, which is our true protagonist—the coffee bean.

Silver skin Inside the parchment layer, the coffee bean is wrapped, and the surface of the bean is still tightly covered by a very thin film, much like rice paper. That is the epidermis left from seed development, and in the coffee industry it is called silver skin or chaff. Most of the silver skin will fall off during processing (especially when the washed method is used). If it has not fallen off, sometimes the "polishing" step is used to remove it before shipment. Even if this procedure is not added, the small amount of remaining silver skin will mostly fall off cleanly during roasting, leaving only a very small amount of fragments caught in the narrow slit of the bean's center line. When the coffee beans are ground, these appear as pale yellow fine flakes mixed in with the grounds.

Endocarp (parchment) Below the mucilage, the layer tightly adhered to by the mucilage is a shell composed of cellulose. Every coffee bean has such a layer, and this shell is the endocarp. After the endocarp dries, its appearance is very much like Western parchment, which is why it is called parchment.

Pectin layer Below the pulp is the pectin layer, also known as mucilage. Mucilage is both sweet and sticky, and coffee farmers habitually call it honey (Miel). In botany, the pulp and mucilage are together called the mesocarp.

Pulp Directly below the exocarp is a thin layer of pulp. Except for the dry process, the outer skin is usually removed within just a few hours after the fruit is picked, and the pulp adhering to the inner side is removed along with it. Therefore, the earliest designed peeling machine was called a depulper.

Exocarp The outermost layer is the epicarp, abbreviated as skin. It is similar to the skin of a cherry or cranberry but somewhat tougher. In most coffee varieties, the fruit is red when ripe, though some are yellow or orange.

▲ Washed green beans

▲ Washed roasted beans

Washed Process:

The washed process uses fermentation to break down the pectin layer. Specifically, the skin of the coffee cherry is first removed, then fermentation is used to decompose the pectin, after which water is used to rinse away the pectin softened by fermentation, and finally mechanical drying is used. The drying stage usually takes one to two days. Of course, sun drying can also be chosen, but that extends the time to three to sixteen days. Compared with natural processing, washed coffee beans are much more convenient to handle. Defective beans can be screened out in large numbers during washing, and washed beans have excellent visual appeal, which is why they are so popular.

Washed coffee is formed through the following steps:

1. Removing floating beans Pour the coffee beans into a large water tank. Underdeveloped, poor-quality beans will float to the surface, while ripe, full fruits will sink to the bottom. At this point, scoop out and remove the floating beans, completing the step of removing floating beans.

2. Removing skin and pulp Use a pulping machine to remove the exocarp and pulp of the coffee fruit. (The pectin, endocarp, and silver skin will remain.)

3. Fermentation The purpose of this step is to use biological processing methods to remove the pectin. The coffee fruit that has passed through the pulping machine.

4. Washing After completing fermentation and removing the pectin, because fermentation bacteria and impurities will remain on the coffee beans, the beans are washed once more. In order to wash them clean, this step consumes a large amount of clean water.

5. Drying and removing the endocarp and silver skin Usually a machine is used (or sun drying is used) to dry the coffee fruit and reduce the moisture content to 10–14%. Then a huller is used to remove the remaining endocarp and silver skin, completing the processing.

Advantages and disadvantages of washed coffee beans

Advantages: 1. All processing procedures of the washed method are indoors, so impurities in the coffee beans can be reduced to a minimum, resulting in the highest quality. 2. Because the pulp is removed at the very beginning, there is completely no need to worry about mold, unlike with the natural method. 3. The appearance is more intact, and the visual appeal is excellent.

Disadvantages: 1. The procedures are complex and cumbersome, so the cost is much higher than that of the natural method. 2. It uses a large amount of clean water. Producing 1 kilogram of coffee beans requires consuming 40–50 liters of clean water, so it is less commonly used in water-scarce regions.

Flavor: Because it undergoes fermentation, the coffee beans usually carry bright acidity and fruity aromas.

During fermentation, biological processing methods are used to remove the pectin. After fermentation is completed, a continuous supply of fresh water needs to be introduced in order to wash away the fermentation bacteria and impurities remaining on the coffee beans, so a large amount of clean water is used. Therefore, it is less commonly used in water-scarce regions. Although the washed process does not require worrying about mold, the fermentation process of washed processing can have a certain impact on coffee flavor, so some specialty coffee enthusiasts do not adopt this processing method. Washed coffee tastes clean with no off-notes, and the coffee beans usually carry bright acidity and fruity aromas.

Front Street Coffee (FrontStreet Coffee) compares two washed beans, Kenya Asaliya and Ethiopian Yirgacheffe Gudingding, to see how coffee beans that are both washed can still differ.

Front Street Coffee (FrontStreet Coffee): Kenya Asaliya coffee beans Region: Thika, Kenya Processing station: Asali Honey Processing Station Altitude: 1550–1750 meters Grade: AA TOP Variety: SL28, SL34 Processing method: Kenyan 72-hour washed

Roast curve These beans are full and round. In order to fully bring out their bright and full-bodied acidity, Front Street Coffee (FrontStreet Coffee) uses a light roast. Machine: Yangjia 800N, green bean charge 550g Charge temperature: 200°C First crack: 5'30", 154.3°C Development after first crack 2'10'', discharged at 191.6°C

Kenyan 72-hour processing method Abbreviated as K72. The coffee fruit is harvested when the ripeness sweetness reaches 21, the best fruits are selected for depulping, soaked in a fermentation tank for 24 hours using clean river water in the tank, then washed after 24 hours, then soaked in clean river water to ferment for another 24 hours, then washed again, then fermented again, repeating 3 times, for a total fermentation time of 72 hours. Even the longest ordinary washed fermentation time is only 36 hours. This repeated processing method of fermenting and then washing gives Kenyan coffee beans a strong acidity and a delicate texture.

Front Street Coffee (FrontStreet Coffee): Yirgacheffe Gudingding Cooperative coffee beans Region: Gedeo Zone, Yirgacheffe Altitude: 1900–2300m Variety: Heirloom Processing method: washed Grade: G1

Roast curve Roaster Yangjia 800N (roast capacity 300g) Charge temperature: 180°C, turning point: 5'00", 149.9°C, first crack: 8'42", 183.8°C, development after first crack 1'48", discharged at 193.5°C.

Brewing suggestion Front Street Coffee (FrontStreet Coffee) conducts the experiment using the same brewing method and data.

Dripper: Hario V60, water temperature: 90°C, coffee-to-water ratio: 1:15; grind size: medium-fine (BG-6S: 80% passing through China standard No. 20 sieve) Brewing technique: staged extraction. Use 30g of water for a 30-second bloom, then pour in a small stream in circles until 125g for the staged break. When the water level is about to expose the coffee bed, continue pouring until 225g and stop pouring. When the water level is about to expose the coffee bed again, remove the dripper. (Timing starts at the beginning of the bloom.) Extraction time is 2'00".

Kenya Asaliya coffee brewing flavor: SL28 and SL34 from Kenya's Thika region, because the beans here have high acidity, clean and clear structure, and the most solid and rich mouthfeel, a full juicy sensation of smoked plum and cherry tomato, with the sweet-and-sour of plum in the middle, and a finish with the fresh fragrance of snow pear.

Yirgacheffe Gudingding coffee brewing flavor: On the palate there are citrus and black tea, and as the temperature changes there are creamy, caramel, and almond notes, with a clearly sweet aftertaste and a clean, fresh, sweet mouthfeel.

From the experiment, it can be seen that even for beans using the same washed process, the final flavor experience will still differ because of other factors such as origin, altitude, and variety.

As for describing coffee flavors, Front Street Coffee (FrontStreet Coffee) believes that everyone will have their own interpretation. What Front Street Coffee (FrontStreet Coffee) truly wants to do is guide friends who are just beginning to explore specialty coffee to find a connection between coffee and their taste buds, and to develop our sense of taste. This process is like a kind of training, a kind of conscious development. And when our sensitivity improves, we can then set aside this pursuit of precise flavors, adopt a more open attitude, feel the richness and changes of coffee, and more purely feel the beauty of a cup of coffee.

The above content is compiled by CoffeeHunters, a coffee news website.