The Three Main Processing Methods of Coffee Beans - Characteristics of Major Coffee Bean Processing Methods

FrontStreet Coffee - Introduction to Coffee Processing Methods

COFFEE PROCESSING

Coffee beans are the fruit of the coffee tree, a perennial evergreen shrub or small tree in the Rubiaceae family. Coffee processing refers to the long and complex journey from picking a fresh coffee cherry to producing green beans. Different regions, countries, and farms process coffee beans in different ways. Today we will mainly introduce the three most basic processing methods.

Washed Processing Method

After depulping and fermentation, with at least three screenings, minimal residual mucilage, the shortest drying time, a clean flavor, high acidity, and a low probability of defects.

The washed processing method is currently the most common coffee processing method in the Yunnan production region.

Processing method: After picking mature coffee cherries, they undergo [① Floating selection] to remove floating dry fruits, then enter a depulping machine for [② Depulping] to remove the skin and screen out unripe fruit, then go to a fermentation tank for [③ Fermentation] until the mucilage completely decomposes, enter [④ Cleaning channel] to wash away mucilage, after which the water is drained, and the beans go to a drying bed for [⑤ Drying] until reaching 12% moisture content, and finally [⑥ Collection and bagging] to await hulling.

Because of the three screenings through floating selection, depulping, and mucilage washing, the result is a cleaner coffee flavor, while the concentrated and unified fermentation makes the flavor more consistent and stable.

Natural Processing Method

Fermentation within the fruit skin, the most primitive coffee processing method, with the most thorough fermentation, the most difficult results to control precisely, and the most aldehyde and lipid aromatic compounds produced by fermentation.

The natural processing method is the most primitive and ancient coffee processing method.

Processing method: After picking mature coffee cherries, they undergo [① Floating selection] to remove floating dry fruits, then the water is drained and the cherries go directly to a drying bed for [② Drying] until reaching 12% moisture content, followed by [③ Collection and bagging] to await hulling.

Because fermentation continues throughout the drying of the fresh fruit, until it dries to 12% moisture content, the drying time is the longest and the degree of fermentation the highest. The resulting flavors are more complex and the aroma the most intense. However, the long drying time and the individual fermentation of each fruit also make this one of the most difficult methods to control and one of the most prone to flavor defects.

Honey Processing

Drying with mucilage after depulping, and not processed with honey; this method is called honey processing. The results often carry jasmine, floral, and vanilla-like aromas, combining characteristics of both washed and natural processing, while saving more water than the washed method.

Honey processing has a fermentation degree between the washed and natural methods, and is also called semi-washed semi-natural processing or pulped natural processing, with many similar names. The key to honey processing is drying with mucilage after depulping, so any processing method with these steps is in fact honey processing.

Processing method: After picking mature coffee cherries, they undergo [① Floating selection] to remove floating dry fruits, then enter a depulping machine for [② Depulping] to remove the skin and screen out unripe fruit, then the residual coffee fruit skins are removed and the beans are transferred to a drying bed for [③ Drying] until reaching 12% moisture content, and finally [④ Collection and bagging] to await hulling.

Because honey processing has a higher fermentation degree than washed but lower than natural, and the parchment with mucilage ferments during drying, the aroma carries more floral and vanilla-like fragrances while also showing washed characteristics. It is a relatively balanced processing method.

Knowledge Point:

The best crops are grown in areas with higher altitude, fertile soil, rich in phosphorus, nitrogen, and potassium, and a mild climate.

FrontStreet Coffee Recommendation

Yunnan is the clearest place to compare processing methods. FrontStreet Coffee's Yunnan Small Cherry comes from Baoshan, is fully washed, and is roasted medium, bringing soft nutty and chocolate sweetness with a light plum acidity at an easy price. FrontStreet's 2013 Yunnan Typica takes the natural route instead: roasted medium, it is fuller and more fruit-forward, with dark berry, caramel, chocolate, a hint of dried apricot, and a black tea finish. Brew either as a pour-over; the washed lot reads cleaner, while the natural lot shows more body and ferment-derived fruit.