Why Are Coffee Processing Methods Becoming Increasingly Complex?

Recently, a friend who is knowledgeable about both wine and coffee complained to FrontStreet Coffee: "When I was learning about coffee, there were only a few processing methods. I haven't paid attention to coffee information for just 2 years, and now the processing methods have become so complex. It's as if every bean needs its own unique processing method."

The complexity of coffee processing methods indicates that the purpose of processing coffee has changed. The emergence of different processing methods was not initially intended to highlight more distinctive flavor profiles, but rather to adapt to the local environment for more efficient processing of coffee cherries into coffee beans.

For example, the introduction of washed processing was not initially intended to create flavors different from natural processing. Instead, in Indonesia, natural processing didn't work. Unlike the environments of East Africa and the Arabian Peninsula, Indonesia's humidity and frequent rainfall made naturally processed coffee beans very likely to remain insufficiently dried and spoil.

Therefore, the Dutch at that time invented washed processing (wet processing method). By removing the peel and mucilage—substances that easily ferment and spoil—the quality of coffee beans improved, and the drying time was also shortened. In Indonesia's humid and rainy environment, natural processing might require 3-4 weeks to complete drying, while washed processing could be reduced to 2 weeks, greatly reducing the risk of moisture-induced spoilage. Later, to极致压缩干燥时长, Indonesia gradually developed the wet-hulling method.

Brazil's pulped natural processing and Central America's honey processing also developed as adaptations to local conditions.

Of course, from the results, we can distinguish that the difference in flavor profiles between various processing methods is mainly reflected in the different substances involved in fermentation. For example, it's generally believed that naturally processed coffee beans have better sweetness and richer layers of complexity than washed processed coffee beans. This is because during natural processing, the peel, pulp, mucilage, and coffee beans all participate in fermentation. In washed processing, however, only the mucilage and coffee beans are involved in fermentation for the first 1-2 days, and after the mucilage layer falls off, only the coffee beans themselves remain.

The complexity of coffee processing methods is precisely because everyone has recognized that different processing techniques can produce different flavors—that is, current processing methods aim to explore and pursue flavor.

Some estates in Central America recognized that the amount of fermenting substances affects the flavor expression of coffee beans, so they derived different processing methods within the honey processing category, such as black honey, red honey, and yellow honey.

Some estates in Colombia recognized that fermenting in different environments would produce slightly different flavors, so anaerobic processing gradually became applied to coffee bean processing. For example, conventional anaerobic natural processing involves placing coffee cherries in a sealed container for anaerobic fermentation before natural sun drying, and then proceeding with the sun drying.

And anaerobic processing is also quite complex, with factors like anaerobic time, anaerobic environment temperature, anaerobic colony control, pH value control, etc. Basically, there's no standard formula—these are all experiences summarized by each estate through their own experiments. This means that some estates, to highlight certain selling points, will make corresponding modifications to the names of their processing methods.

For example, some estates highlight different durations of anaerobic fermentation as their selling point, and they will add time to distinguish their processing methods, such as 72-hour anaerobic natural processing, 144-hour anaerobic natural processing, etc.

For example, some estates highlight controlling the temperature environment of anaerobic fermentation to control the fermentation of coffee beans, so their processing method names might be "low-temperature slow anaerobic washed processing."

For example, some estates add enzymes (proteases) to assist fermentation during processing, and in their naming, they will write "anaerobic enzyme washed processing."

Another reason why current processing methods appear increasingly complex is that previous naming of processing methods was not particularly refined or precise. For example, although both are expressed as washed processing, there are significant differences in the washed processing procedures between Ethiopia and Kenya.

Conventional Ethiopian washed processing first involves floatation to screen out bad beans and debris. After depulping, the coffee beans are placed in fermentation tanks for 48-72 hours, then the fermented coffee beans are rinsed into another clean water tank for 4-8 hours of soaking. After washing off the mucilage, they are dried in the sun.

Conventional Kenyan washed processing first involves floatation to screen out bad beans and debris. After depulping, the coffee beans are placed in fermentation tanks for 12-36 hours, then manually rinsed and guided to another clean water tank for 12-36 hours of soaking and fermentation. Then the clean parchment beans are dried in the sun.

Some processing stations in Kenya also use dry fermentation (washed) processing, which differs from the method above in that no water is added during the initial fermentation. Typically, after 6-8 hours of waterless fermentation, water is added to rinse the coffee beans, then the water is drained, and this process is repeated several times. The second tank processing is the same.

Although both are washed processing, different processing techniques result in different coffee flavor expressions. However, in the description of the processing method, they are still identified as washed processing.

In summary, the reason why today's processing methods are so numerous and complex is actually due to the consumer market's pursuit of coffee flavors and the importance placed on coffee bean traceability information.

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