The processing stage can be further divided into:
- Processing with cherries
- Drying the beans
- Milling the beans
Processing with cherries
A coffee cherry contains : Outer Skin (cascara), Pulp, Mucilage, Parchment, Sliver Skin and Bean. (From exterior to interior).
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Cherry processing is the procedure of removing the multiple layers of coffee cherry to Parchment layer level. The main three common processing methods are Natural Process, Honey Process, Wet Process.
Checkout a summary for the flavor of each process and how to distinguish them!
Natural process (dry process)
Often dubbed as dry processed, is a traditional method of processing which originated in Ethiopia. This process require less water as implied in the name and hence it is common in regions where there is no access to water such as Ethiopia and some regions in Brazil.
Natural process dry the cherries directly after picking and sorting from the coffee trees. The ones that are not ripe enough or over ripe will be discard. After that the cherries are placed under the sun for drying. The main point of natural process is that the cherries are keep intact for drying, which cause the fruity flavor in the processed coffee bean.
As time past, the coffee will ferment and the cherries will turn from red to brown. During this process, human has to keep raking these cherries to prevent them from spoiling. Due to the cherries contains mucilage while drying, the sweetness will latch onto the seeds. Once the cherries are properly dry, the skin and dried fruit flesh are removed mechanically and the green coffee is stored before exporting it.
Natural process is hard to replicate since the fermentation is inconsistent each time. Also, it requires
Usually, natural processed coffee beans tend to possess complex taste and aroma.
Washed Process
For washed process, unripe coffee cherries are also removed in the beginning. Nonetheless, we put all the cherries in a floatation tank and removed those floating on the top. (unripe cherries has lower density). Then, the rest of the cherries are inserted into a depulping machine to remove the pulp. After that, they are placed in water tanks to ferment for 18~36 hrs. Subsequently, the beans are rinsed and dried under the sun for 1~2 weeks. The water ultimately washes the rest of the mucilage and fruit caked onto the seed. At last, the seed are exposed under the sun to dry.
The flavor of washed coffee are usually fresh and bright. There is typically more brightness as well, because of a cleaner acidity that balances out the sweetness of the coffee. The cons of washed coffee is that it require large amount of water, which is not environment friendly.
Honey process
It combines natural process and wet process. After sorting the cherries, the depulper remove the cherry from the seed but remain certain proportion of mucilage, which determines the sweetness. According to the percentage of mucilage remain, we can roughly categorize them into 4 levels: Black (80%), Red (60%), Yellow (40%), White (20%). The percentage may varies for different processing factory.
Drying the beans
Milling the beans
Reference