Flavor Differences Between Natural and Washed Coffee Processing Methods - Roasting Recommendations

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Introduction

Innovative coffee bean processing methods are making coffee flavors special, breaking many people's fixed ideas about coffee taste. However, for many coffee enthusiasts, traditionally processed coffee beans are eternal classics! Especially washed and natural processing methods, without excessive flavor interference, allow you to truly experience the flavors of coffee growing regions.

FrontStreet Coffee has cupped many different processed coffee beans. Regardless of the origin, washed processing best represents the fundamental character of a coffee bean, while natural processing enhances the fruit aroma and full-bodied texture. When recommending coffee beans to beginners, we always start with washed or natural coffee.

What is Natural Processing?

Sun drying is people's most primitive method for drying food, and the principle of natural coffee processing is the same. However, traditional natural processing places coffee cherries on drying patios or directly on roadsides for exposure. Due to crude conditions and rough handling methods, natural coffee quality varies greatly with high defect rates. The causes of defects also come from strong weather dependence - during the month-long drying period, continuous stable high-temperature dry weather is needed. If it rains during drying, coffee cherries will mold.

But as the coffee market demand grows and people's requirements for coffee bean quality increase, many large coffee processing plants continuously optimize natural processing details to improve the cup quality of natural coffee. Before drying, floating selection is performed to remove coffee cherries with insufficient density. Drying sites are also strictly controlled, such as building African raised beds and cement drying patios. During the natural process, to ensure even drying, many processing plants or estates hire workers to regularly turn the cherries, ensuring uniform drying while avoiding over-fermentation and reducing defects.

The flavor of naturally processed coffee beans mainly comes from the sugars absorbed from the coffee pulp and mucilage during drying. During the month-long drying time, coffee beans have sufficient time to absorb these sugars, enhancing the coffee's sweetness. Although natural processing is simple, it depends on weather conditions. Regions with short sunshine times, low temperatures, or high humidity are not suitable for use. To shorten natural drying time, wise coffee farmers created the washed processing method.

What is Washed Processing?

Washed processing differs from natural processing as a quality-stable processing method. During processing, washed processing first performs floating selection on harvested coffee cherries, similarly removing cherries with insufficient density. Then machines remove the pulp, and the beans are placed in water tanks for either anaerobic or water fermentation, using fermentation to decompose the mucilage layer. After fermentation is complete, coffee beans are washed with clean water to remove mucilage, and finally the mucilage-free coffee beans are sun-dried to reduce moisture content to 11% to 13%.

Because floating selection screens out bad fruits and reduces drying time, washed coffee quality is more stable. Meanwhile, the fermentation method of removing mucilage enhances the coffee's acidity. If coffee shows over-fermented or rotten flavors, these defects will be amplified by the acidity. FrontStreet Coffee believes washed processing most directly reflects the quality of coffee beans. Although washed processing reduces weather dependence, it requires large amounts of water resources, so it's not suitable for water-scarce regions.

Distinguishing Washed & Natural Processing by Observing Coffee Beans

Washed and natural processed green coffee beans have very obvious differences in appearance. If you compare washed and natural processed green beans side by side, washed processed green beans have a distinct bluish-green color, while natural processed green beans have a yellowish color.

For roasted washed and natural coffee beans, we can observe the center line of the beans. Beans with a white center line are washed processed, while those without a white center line are natural processed. Because natural beans have their outer silver skin completely connected, the silver skin attached to the center line easily falls off together, so after roasting, natural roasted beans have very clean silver skin removal, leaving no silver skin residue on the center line. Washed processed coffee beans are the opposite - because there's almost no silver skin connection on the outer layer, the silver skin in the center crack cannot easily peel off, so silver skin residue remains on the bean's center line.

What Should Be Noted When Roasting Natural vs. Washed Processing?

Washed and natural processed coffee beans also have differences during roasting. The roaster at FrontStreet Coffee explains that washed processed green coffee beans have slightly higher moisture content than natural processed green coffee beans. Therefore, when comparing the roasting of these two processing methods, roasting washed coffee beans requires extending the dehydration time.

The dehydration stage generally refers to the period from when green coffee beans enter the roaster until they complete dehydration and turn yellow. During the entire coffee roasting process, moisture is continuously being removed, but most of the green coffee bean's moisture is removed during this stage.

During the dehydration stage, the green bean's structure is most complete and most heat-resistant. This stage requires sufficient heat to heat the green coffee beans, increasing the temperature difference between the bean surface and core, allowing coffee beans to quickly absorb heat and build up sufficient thermal potential and core pressure during this opportunity.

Because as coffee roasting progresses, the coffee bean structure becomes increasingly fragile, but the formation of flavor compounds requires sufficient heat. Therefore, if enough thermal potential is not built up during early roasting, adding heat later will easily burn the coffee bean surface. Of course, during the dehydration stage, even when achieving a large temperature rise rate, control must be maintained, otherwise it will also scorch the beans.

Flavor Differences Between Washed and Natural Processing

FrontStreet Coffee believes that washed processed coffee has higher acidity and cleanliness, but complexity and layering are not as good as natural processing, while natural processed coffee has stronger berry aromas, is more complex, and sweetness tends to be higher than washed processed coffee.

For more specialty coffee beans, please add the private WeChat of FrontStreet Coffee, WeChat ID: kaixinguoguo0925

Important Notice :

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