The 4 Most Common Processing Methods: What's the Difference Between Natural, Washed, Semi-Washed, and Honey Processing?

There are four most common processing methods for coffee beans: natural process, washed process, semi-washed process, and honey process. So what specific procedures are adopted for different processing methods, and what types of flavor characteristics do they present in coffee beans? In this article, FrontStreet Coffee will take everyone to understand.

Natural Process

Natural process, as the name suggests, involves drying under the sun. It is the most cost-effective, simplest to operate, and most traditional coffee bean processing method. It is most commonly adopted in producing regions that lack water resources but have abundant sunlight, such as Ethiopia in Africa. For example, FrontStreet Coffee's own roasted FrontStreet Coffee Ethiopia Guji Coffee, FrontStreet Coffee Panama Emerald Red Geisha Coffee, FrontStreet Coffee Brazil Queen Estate Coffee, and FrontStreet Coffee 2013 Typica Coffee are all produced using natural processing, presenting a full sweetness after brewing.

Coffee cherries processed naturally will first be sorted to remove unripe fruits and impurities (such as stones), then spread under the sun to evaporate the moisture from the pulp outside the beans through sunlight. When the target moisture content is reached, machines can be used to crush the shell and extract the coffee beans with parchment. Since natural processing does not require high technical skills, basically every small farmer can process it themselves. The entire drying process only requires sunny daylight, so the production cost is lower, making it most common in high-altitude coffee growing regions.

Regions pursuing refined flavors will first float the coffee cherries to remove unripe fruits and gravel debris, then spread them evenly on raised drying beds to dry, aiming to stay away from the ground to prevent infection by crawling insects, dust, and bacteria. During the natural drying period, dedicated personnel will check the drying degree of coffee cherries and pick out worm-damaged fruits, cracked fruits, and moldy fruits to avoid these bad fruits affecting other coffee.

Because the inner beans of natural coffee are wrapped in pulp throughout the drying process, the fermentation time of coffee cherries is longer, and the degree of reaction between microorganisms and pulp is higher. When the fruit begins to ferment, microorganisms produce more volatile compounds, especially esters. These aromatic substances provide more floral and tropical fruit fermentation aromas for the roasted coffee beans, such as furan compounds, making natural coffee have a wider flavor range and taste sweeter.

Washed Process

Producers first need to use machines to remove the skin and pulp from the harvested coffee cherries, put the de-pulped coffee beans into fermentation tanks for fermentation, use fermentation to decompose the mucilage layer, repeatedly wash the fermented coffee beans with clean water to wash away the decomposed mucilage, and finally dry the coffee beans in the sun for 1-2 weeks. Finally, the dried coffee beans can be stored and transported to various places.

Since each step can remove impurities and defective beans, the quality of the raw beans is more uniform. Additionally, regions using the washed process must build washing tanks and be able to introduce a continuous supply of fresh water, so the final transaction price is also higher than that of naturally dried coffee. Washing not only greatly reduces the defect rate of coffee but also brings a clean, delicate taste to high-quality coffee beans. For example, FrontStreet Coffee Ethiopia Gedeb Cooperative Coffee, FrontStreet Coffee Kenya Asalia Coffee, and FrontStreet Coffee Emerald Estate Green Geisha Coffee on FrontStreet Coffee's bean list are all processed using the washed method, presenting bright and full acidity.

Semi-Washed Process

The semi-washed process involves first picking out leaves, stones, and other off-flavors from the harvested coffee cherries, pouring them into water tanks to remove unripe fruits through flotation. Machines are used to remove the skin, pulp, and part of the mucilage layer, then wash for one hour. Due to the short soaking and fermentation time, the mucilage is not easily completely washed away. The parchment beans with some mucilage are spread on drying grounds to dry. The semi-washed method not only saves water resources but also saves labor costs. Compared to traditional natural drying, it takes less time, so it is widely used in Brazil.

FrontStreet Coffee's FrontStreet Coffee Brazil Cerrado Daily Bean is processed using the semi-washed method, and the multi-stage screening greatly improves the cleanliness of the coffee beans. Another FrontStreet Coffee offering, FrontStreet Coffee Brazil Queen Estate Coffee, uses refined small-batch natural processing. Large-scale production may cause over-fermentation due to untimely turning, producing undesirable fermented flavors. The entire drying process of raw beans at Queen Estate is carried out in small batches on African raised beds, thereby avoiding earthy and fermented flavors, and its sweetness is also a step above traditional semi-washed processing.

Honey Process

The honey process can be said to be a compromise between natural and washed processes, therefore it is also called semi-washed/semi-washed, and is more common in countries in Central and South America.

When producers use the honey process method, they first pour fresh coffee cherries into water tanks to remove unripe fruits and impurities through flotation, then use a pulper to remove the outermost layer of the fruit. Unlike the washed process, after the fresh coffee cherries have their skin removed, they are not rinsed with large amounts of clean water to remove the mucilage, but instead retain the mucilage for drying. Because there are sugars in the mucilage and its state is sticky, it easily reminds people of honey, hence the name honey process.

The subsequent steps of the honey process involve fermenting coffee seeds while the viscous mucilage is still present. According to the sugar content and fermentation state of the fresh coffee cherries, producers will give different names, such as white honey, yellow honey, red honey, and black honey. Darker colors mean the coffee seeds ferment longer in the mucilage and the mucilage undergoes deeper oxidation. Compared to the washed process, the honey process does not require large amounts of fresh water and related equipment, and also reduces the defect-negative flavors that come from long exposure to sunlight. Coffee processed using the honey method generally presents rich tropical fruit flavors and fermented sweetness in cupping, with an overall refreshing taste and clean acidity.

There is also a raisin honey processing method, where coffee cherries are dried on raised beds for at least three days before removing the skin and pulp, allowing the fruits to dehydrate and shrivel into a "raisin" state, before proceeding to remove the skin and pulp and continue with the subsequent honey processing steps.

The characteristics of the raisin honey processing method are "retaining 100% mucilage" and "zero water processing," which increases the difficulty of the raisin honey processing method. According to FrontStreet Coffee's analysis, this requires strict time control, making it more difficult than black honey processing. The initial drying step of raw beans allows the aromatic flavors of the pulp to penetrate into the raw beans under sunlight heating, so coffee processed using raisin honey not only has rich floral and fruity sweetness but also clear sweet and sour flavor profiles. FrontStreet Coffee's FrontStreet Coffee Costa Rica Mozart Coffee Beans are processed using the raisin honey method.

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