During its production process, coffee goes through several stages: cultivation, harvesting, processing, roasting until it reaches the consumer. In this article, we will talk more about the part that encompasses coffee processing, which is a set of procedures for drying and homogenizing the beans.
It is during processing, for example, that the separation of green, ripe, past fruit, etc. occurs. Consequently, this is also a prime factor in the pursuit of drink quality. There are three ways to accomplish this process and they are what we will know now.
Three ways of coffee processing
Let’s start by doing a coffee fruit analysis. This will make it easier to understand the different forms of grain processing. The fruit has the following ‘layers’:
- Bark – With the ripening process, it changes from green to red or yellow;
- Pulp – located just below the shell, it is quite fleshy;
- Mucilage – situated between the pulp and parchment, it is a viscous layer rich in sugars;
- Parchment – is a very thin film that surrounds the seed;
- Seeds or Grains – is the coffee we are used to seeing in photos and videos. Each coffee fruit contains two seeds (or beans).
After the X-ray of the fruit, we will know how the processing step works.
At harvest, the discrimination of harvested fruits is in many cases low. Then, right after the first selection is made: the fruits are poured on large mats containing running water, where the drier fruits that have lost moisture in the foot, floats (known as “floats”) are removed. This is because these are malformed fruits (chocho coffees, poorly grenaded) and may have been attacked by pests (broccoli).
From there, we also remove the greens (undesirable for their astringency) and the good fruits, known as cherries (those that give rise to specialty coffees), go to processing. There are three distinct forms.
Natural or Dry Preparation
The Natural process is the most used in the world and is the oldest form of drying of coffee fruit. It is widely used in warm climate. The beans are scattered in a yard, exposed to the sun or in artificial dryers, and removed several times for even drying.
In this process, pulp (red or yellow peel) and grains are dried together. The outer shell of the fruit acts as a protective cover, so that drying is slower, keeping the pulp between the shell and the seeds intact. If conditions are right, fermentations can occur in this pulp, which are responsible for the formation of aroma notes like floral and even fruit like ripe banana, enhancing the drink. In general, this process gives rise to a sweeter and fuller drink.
Peeled or Wet Preparation
The Peeled process emerged as an alternative for faster drying and the use of a smaller area of yard, since the removal of the outer shell decreases the fruit volume by almost half.
In this case, the green fruits and the cherries go together to a peeler, equipment that presses them against a cylinder full of holes and through which the (larger) cherries pass and the greens are retained. During this process, the cherry fruit easily loses its rind and goes straight to the yard or dryer – the mucilage remains in the coffee bean. This is why it is called peeled cherry (CD).
The method is ideal for wetter regions because it prevents bad brewing of coffee – without the outer shell the dehydration process is much faster. However, it requires high investments in equipment, labor, energy and proper disposal of wastewater from this process. Tends to a drink with intense sweetness and balanced acidity.
Pulped, washed or semi-wet
Already in this process, the peeled cherries do not go to drying. They go to large pools of water, where they stay between 12 and 48 hours in the presence of microorganisms. They are responsible for the elimination of grain mucilage.
After fermentation, the beans are washed and taken to dry in the yard or dryers, keeping only the parchment. The drink made with these beans is slightly fuller than Natural, and will be more fruity, floral and acidic.
This is not a new type of grain processing as it is very similar to CD. The big difference is in the time to depulp: in addition to eliminating the bark, a small amount of mucilage is removed. Here the coffee is piled up or in thick layers to undergo some fermentation.
The name is because the coffee seems to have been dipped in honey because it looks sticky. There are variations where the color will depend on the fermentation time and amount of mucilage, which are: white, yellow, gold, red and black honey. Result in a sweeter drink
And which one gives the best flavor?
It is important to note that all harvested coffee beans are traded, from coffee buoy, to natural, peeled cherry, pulped to greens. It is the sensory characteristic that each of them provides that makes its added value measured.
It is difficult to tell absolutely which processing yields the best coffee, as each consumer market seeks a particular sensory characteristic (personality) that one of the three processes (natural, peeled, pulped cherry) provides.