Coffee Introduction - Guide to Washed Coffee Processing and Brewing Methods

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The Washed Coffee Process

Washed processing requires special machinery and ample water supply. When properly processed, it can better highlight the unique characteristics of the coffee beans themselves. Moreover, defective beans can be largely removed during the washing process, improving the overall quality of the coffee beans. The washed coffee process is widely used in Central and South American countries.

When coffee cherries are harvested from the mountains, the next step is to remove the peel and pulp to obtain the coffee beans. There are two main processing methods: washed and natural. The ultimate deciding factor is whether there is sufficient water supply available. Some specialty coffees use both natural and washed methods.

After harvesting, coffee beans undergo preliminary sorting to remove impurities. Then, truckloads of coffee beans are transported and poured into large water tanks, where clean, flowing water washes the beans through channels. Mature coffee beans should have higher density and sink to the bottom of the channels. Damaged coffee cherries, branches, leaves, and lighter impurities float on the surface and are filtered out and removed from above the channels.

After being washed and sorted through the channels, the mature cherries pass through a depulping machine to remove the pulp. This step is the most different from natural processing, as in natural processing, the coffee pulp and beans are not separated beforehand.

At this point, the outer layer of the coffee bean still has a viscous, soft parchment that protects the integrity of the coffee bean. The washing process should be carried out immediately after coffee harvesting to avoid pulp rot causing flavor contamination and reducing the quality of the coffee beans.

Next, the coffee beans are placed on mechanical screens. The vibrating screens separate immature and defective beans that were not separated in the previous washing step. Successfully filtered coffee beans are placed back in channels for a second round of cleaning and sorting with clean water.

Fermentation Process

Due to the depulping machine, some residual pulp will inevitably remain attached to the coffee bean parchment. At this point, the coffee beans are placed in fermentation tanks where natural enzymes break down these residual pulps and parchments. The fermentation process typically ends within 24-36 hours, depending on temperature, thickness of residual pulp, and enzyme concentration. Then, the coffee beans are washed again with clean water until the pulp and parchment are removed. The fermentation process must be strictly monitored, otherwise, some undesirable sourness or flavors may contaminate the coffee beans. After processing, the surface of the coffee beans becomes rougher, losing their previous viscous feel.

Drying Process

After fermentation and washing, the coffee beans have a moisture content of about 57%. Because the coffee beans are too moist, they are typically dried using machines or sun-drying to reduce the moisture content to 12.5%. If machine drying is used, it usually takes 2-3 days to effectively reduce the moisture content to the ideal level. If sun-drying is used, it requires favorable weather conditions, and the time will extend to 1-2 weeks.

Final Processing

When the moisture content of the coffee beans is effectively reduced to 12.5%, the coffee beans are stored for export. Finally, before coffee export, the dried parchment and the final layer of silver skin are removed using machinery. Then, the beans undergo cleaning, screening, sorting, grading, and packaging steps.

Characteristics of Washed Coffee

Washed coffee beans can provide a cleaner taste without impurities and have an attractive fruity aroma. Washed coffee beans tend to be more blue-green or gray-green in color. The taste of washed coffee is clearer, distinctly bright, and free of impurities.

Through cupping multiple washed process coffee beans, FrontStreet Coffee found that due to the fermentation step, the overall character of the coffee beans is very clean and bright, which also greatly tests the quality of a coffee bean. FrontStreet Coffee believes that the quality of a coffee bean, when processed using the washed method, is revealed without doubt, and can also很好地表现 the unique flavors of the coffee-producing region.

Among the many coffee beans offered by FrontStreet Coffee, there is a series of regional selected daily coffee beans. Except for Brazil and Indonesia regions where natural processing is used due to regional conditions not allowing washed processing, the other five regions of Ethiopia, Guatemala, Colombia, Costa Rica, and Yunnan all use washed processing for their selected daily beans. We hope that everyone can recognize the basic flavors of popular coffee-producing regions in the most cost-effective way.

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