The different drying processes of coffee
Coffee is an exotic product, like cocoa, which can only be cultivated in certain regions of the world.
Before being a beverage, it is a green bean that comes from the fruit of the coffee tree, called cherry.
Once harvested, the coffee cherries must be dried to extract the bean, and the method used has a strong impact on the aromatic profile of the coffee.
Drying is a process that allows a controlled fermentation to soften the parchment of the cherry to extract the beans more easily.
The term "coffee processing" is actually the drying method used to transform the cherries into green beans, which are then roasted.
There are 3 main processes:
NATURAL (dry)
This is the traditional method, also called "natural coffee" or "natural coffee" because the cherries remain whole.
- Where is it used?
Countries using the dry method.
In countries where the dry season is well marked: Brazil, Ethiopia, Panama, Costa Rica.
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How long does it take to dry? Between 10 and 30 days
- What is the principle? The cherries are spread out in a layer that should ideally be the thickness of 2 cherries. This can be on a concrete floor, or on raised African beds. They must be turned regularly in order to have a uniform fermentation of the cherries. They are covered at night to protect them from humidity. The moisture content of the cherries, during this process, decreases from 70% to 15-30% during the drying process, and then to 10-12%, which is an ideal level for a good conservation of the beans.
Drying on the ground. Source : lafabriqueducafe.fr
Drying on raised African beds. Source: black-coffee.fr
- What are the results on coffee? The result will be intense fruit aromas and full-bodied coffee.
WASHED (wet)
This process was developed by Dutch coffee growers in the 17th century on the island of Java. Natural drying was impossible because of the high humidity and heavy rainfall. 
The beans are regularly stirred for a homogeneous fermentation. Source: javry.com
- Where is it used?
Countries using wet drying.
In countries with high humidity: Ethiopia, Kenya, Rwanda, El Salvador, Colombia, Panama.
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How long does it take to dry? From 4 to 10 days
- What is the principle?
- What are the results on coffee? Cleaner than natural coffee, but with less body and more acidity.
HONEY
A so-called "hybrid" method, mixing aspects of the dry and wet ways.
Also called "pulped natural" outside Brazil in Central America.
Yellow, red and black honey
There are different degrees of honey process depending on the percentage of mucilage left on the parchment of the grains. The more mucilage is left on the parchment, the darker the color of the parchment is when dried in the sun. 
The different degrees of honey process according to the % of mucilage removed.
- Drying time ? 7 to 12 days
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What is the principle? Depulpers separate the ripe cherries from the immature ones. The kernels covered with mucilage attached to the parchment are then sun-dried on African beds in layers of about 2.5 to 5 cm (1 to 2 inches). They are then turned regularly to obtain a homogeneous drying.
- What are the results on the coffee? A rather clean coffee with more body than a washed coffee, but also less acidity. A taste in cup closer to natural coffees.
TABLE OF ADVANTAGES AND DISADVANTAGES OF THE PROCESSES
Source: book "Le café c'est pas sorcier", available at Ma Caféine.
