The dry processing or natural process, is the green bean processing method with the longest history among all coffee processing methods. As the name implies, the natural processing method is to place the picked and screened coffee cherries in the sun to dry and dehydrate.
The traditional natural process is generally carried out on the concrete floor, and later it is also placed on the terrace made of bricks, custom-made sunbeds, etc. During the drying process, the fruit must be turned constantly to avoid moldy or excessive fermentation of the fruit. After the fruit is dried, the peel, pulp, and pectin are removed by machine, and the bean shell (dried endocarp, also known as “parchment”) is kept for preservation before sale. The whole process takes about half to a month.
The natural process is also the fermentation process of the fruit. Therefore, whole fruit fermentation can allow more substances to remain in the coffee beans, making the flavor of the coffee present a rich and complex character, and the sweetness is more obvious. There is no washing step, so many substances can be retained, but the cleanliness is low and the acidity is not too high.
It can be seen that the natural process method can not only make the coffee taste better but also save water resources through a relatively simple treatment process. It is suitable for areas with sufficient sunlight and a lack of water resources.
And the processing time is longer, requires a larger space and continuous flipping operations, the cost of time and the requirements for the site are high, and the demand for manpower is also large.
If it is spread on the ground, it will be easily mixed with impurities or contaminated with a bad smell, which will affect the subsequent processing and the quality of raw beans. Today, a considerable part of the world’s coffee still uses natural processing, such as in Ethiopia, Brazil, Yemen, and so on.
Processing steps: picking-screening-drying-peeling to pectin
Flavor characteristics: low acidity, obvious sweetness, slightly low cleanliness, high complexity
Advantages: more flavors are preserved, the processing process is simple, and water resources are saved
Disadvantages: subject to weather constraints, long processing time, large demand for manpower and space
Representative coffee or region: Ethiopia, Yemen, Brazil