There are currently three main methods of coffee processing, which we would like to introduce to you in more detail:
- Washed method
- Dry method (natural)
- Honey metoda
Coffee processing by washed method
This method is the most widely used of all coffee processing methods. The main reason is that the washed processing process can highlight the grain qualities best compared to other methods. That is why most selected coffees are processed in this way. The resulting taste of the coffee processed by this method is then cleaner than, for example, the dry method. These coffees better describe the origin and variety of coffee. Another bonus is that the washed processing method has a lower risk of unwanted fermentation and mold growth. The disadvantage of this treatment method is the amount of water consumed.
With this method, the goal is to remove the skin and all the flesh. Even before drying the coffee beans. The procedure is as follows:
- First, the husk and pulp are mechanically removed from the grain
- The grains and pulp residues are placed in a fermentation tank for 10 to 72 hours, where they are allowed to ferment
- After fermentation, the grains are freed from the last remnants of pulp and mucus thanks to washing with water
- The grains are allowed to dry in the sun or in the shade for optimal humidity
- The last stage is the peeling of the grains from the parchment
Dry coffee processing (natural)
As part of the dry method of coffee processing, whole coffee cherries, including pulp and skin, are dried. This method of processing is cheaper, however, it requires specific climatic conditions necessary for sufficient drying of coffee fruits.
With careful collection and drying, coffee processed by the dry method offers excellent aroma and sweet taste. As a bonus, it is also the most environmentally friendly processing method. If the dry processing process is done correctly, it will give the coffee a fuller body and a very interesting taste with a touch of fruit.
Dry processing procedure
- The collected coffee cherries are spread in thin layers for drying in the sun - concrete terraces or so-called African beds are used for this, which are raised and thus allow better air flow, which of course speeds up the drying process.
- During drying, the cherries must be turned and aerated regularly to prevent the development of mold and unwanted fermentation.
- The dried cherries are mechanically cleaned - the skin and flesh are separated from the grain
Honey coffee processing
The honey coffee processing method is a combination of both methods - dry and washed. When this method works well, the resulting coffee taste is very complex. Other subcategories are known within this coffee processing: yellow, red, gold, black or also white honey. The undeniable advantage of the Honey method is its low consumption of the amount of water used for coffee processing.
What influences the final taste of coffee the most, apart from the region, the climate during cultivation and the variety, is its processing. With the Honey method, two basic factors depend on processing. The first is the amount of pulp and slime left on the grain. The second decisive factor influencing the quality is the length of the drying and the solar intensity during it.
The Honey method preserves some of the desired taste aspects of dry-processed coffees. They are mainly robust body, sweetness of ripe fruit and low acidity. At the same time, depending on the chosen method (white, yellow, red ...), it retains its original taste properties in coffee, which would be most pronounced when processed by the washed method - freshness, fruitiness and juiciness.
Basically, this means that the more pulp and juice (slime) is left on the grain, the closer the coffee is to natural coffees and the less close they are to washed coffees. This method speeds up the time the grains dry. This reduces the risk of mold development. The grains need to be aerated very well. There must be no excessive fermentation that takes place in this process at the same time as the coffee is dried. Prefermented tones in coffee are not entirely desirable. If there are too many, they may not be perceived positively. The greater risk that coffee will be re-fermented is with coffees that have a higher percentage of pulp and juice left on the grain. Inadequate coffee care can degrade the entire harvest.
Honey processing procedure
- The first step is to selectively harvest only ripe coffee fruits.
- Coffee cherries can pass through a water sorter, as is the case in Brazil. At this stage, the first qualitative division is made on the basis of fruit density. In Costa Rica, this sorting phase is omitted and the processing itself proceeds directly.
- On the disc shredder, the coffee cherries are stripped of a certain percentage of the pulp according to the farmer's request.
- Furthermore, the grains thus treated are dried to the required moisture.
- After drying, the grains are stripped of their outer skin (parchment) and can be further sorted and packaged.
In addition to these 3 basic methods of coffee processing, there are also so-called experimental methods. Examples include: carbonic maceration and anaerobic fermentation.
In anaerobic fermentation, post-harvest coffee cherries are placed in an airtight fermentation tank to prevent oxygen from entering and the fermentation takes place in an anaerobic environment.
Carbonic maceration, a technique that originated in viticulture, is similar. After harvest, cherries are impregnated in an airtight tank, as in anaerobic fermentation. CO2 gas is blown into the tank under pressure. In short, processing coffee in this way places more emphasis on fermentation. It is also ideal to check the temperature in the tank during this method of processing. As a result, the grains absorb more sugars and acids from the surrounding cherries. This leads to the development of complex, unusual and sometimes even extreme taste profiles.
Experimentally processed coffees are generally very rich in taste.