How is coffee processed after harvest?
Raw coffee, before being imported into Italy, undergoes processing still on the plantation.
These activities are essential to allow the roaster to roast the coffee at its best, having a bean ready for "cooking".
But how is coffee processed after harvest? What methods are there? And what taste differences do they present in the cup?
There are 2 main methods of processing raw coffee:
The natural or dry processing method
The beans are hung out in the sun to dry, still contained within the drupes, that is, the cherries found on the coffee plant.
At the end of drying they are peeled, that is, the peel and pulp are removed, extracting and storing only the grains.
This process makes the final coffee in the cup, if well roasted and extracted, soft, rich and full-bodied, with sweet and fruity notes.
In fact, by leaving the pulp to dry too, you have time to transmigrate the sugars inside the grain, accentuating its sweetness.
The washed or wet processing method
For this type of processing, which in the final cup expresses greater acidity and a more delicate fruity and floral notes, we try to use selected Arabica coffees, free from defects. They are also collected with the picking method, that is an accurate manual selection of only the ripe drupes at the right point.
Once the drupes are placed in separation tanks with clean water, for further quality control so that the ripe and immature cherries fall to the bottom, while the dry and rotten ones remain afloat. The latter will thus be eliminated.
At this point a mechanical stripping takes place, keeping only the raw brans still covered by the parchment, that is the thin membrane that surrounds each single bean.
The beans are then placed in water tanks where they ferment for a number of hours and / or days established by the plantation after a series of tests and experiences.
At the end of the washing, the beans always go through a drying phase in the sun, as in the natural method.
It should be emphasized that the drying phase is one of the most delicate, as, if not well cared for, the grain over-ferments, then bringing hints of rottenness, mold or alcohol content into the cup.
There are also distinctions on how drying takes place, but we'll talk about them in another article.
In addition to these two main methods, however, other variants have been added in recent years, such as semi-washed, honey process and wet hulled.
The first, the semi-washed method, is a cross between the natural and the washed, as:
- Harvesting is always manual and selective as for the washed method;
- However, the selection of the drupes and their stripping is done manually or mechanically, as in the natural method;
- Finally, the beans undergo a pressure water wash, which step marks the main difference with the natural method;
- The processing always ends with the drying phase in the sun.
In the cup, a semi-washed coffee is clean and delicate, with good acidity, but also a good body, leaving room for sweetness.
If you want to test on your skin the differences that the different processes bring to the cup, I suggest 3 single origins from Ernani:
- Sidamo Etiope, a washed Arabica coffee, which has a marked acidity, a good delicacy and more fruity and floral aromatic nuances FIND OUT MORE >>
- The Indian Kalledevarapura, a semi-washed Arabica coffee, with a good acidity, balanced by a good sweetness, and an incredible aromatic range FIND OUT MORE >>
- The Brazilian Santos Cerrado, a natural Arabica coffee, with a good sweetness and an almost absent acidity, intense and with hints of chocolate FIND OUT MORE >>
The second instead, namely the Honey process, which originated in Costa Rica, is perhaps one of the most delicate.
Don't be influenced by the name, which depends only on the gel-like consistency that the pulp takes on during the drying phase.
Being a very delicate and complicated method, it is mainly used for coffees of a certain quality, harvested with careful manual selection.
This is followed by stripping, leaving however a layer of mucilage, or pulp, on the beans. As with the natural method, it allows the sugar to migrate into the bean, making the final cup sweet and intensely aromatic.
Depending on how much mucilage is left on the beans, there is a division of the honey into Black method if it is 100% present, Red if 75% is left, Yellow if 50% remains and finally Golden or White if it is present. it is left between 25% and 10%.
Drying always takes place in the sun, but takes longer.
The risk of over-fermentation, with the consequent damage to the beans is very high, which is why it is complicated and delicate, and its use requires great experience and attention from the growers.
And finally we come to the Wet Hulled method. It is little used today, being still a novelty, due to its particular processing.
There is always a meticulous and manual harvest of the beans and a pulping.
At this point the parchment beans undergo a fast fermentation in plastic sheets, before being washed.
After which they are dried in the sun, but only partially, up to 50%.
It is the only method that features the removal of the parchment before the end of total drying. In fact, when the bean is humid at 25/30%, the last thin layer is also removed, defined as already said parchment, and it is only after drying.
In this case, the final coffee in the cup is sweet and complex, with a great personality.
A last method, modern and for this reason still very little used, is Carbonation, in which the beans are fermented in cask, as is the case for wine, with the addition of CO2, or carbon dioxide.
With this article we have come to the conclusion of our high level descriptions of the cycle of processes that take place on the plantation, before the beans are imported and arrive at the roaster, ready for "cooking".
From this it is clear that the quality of a coffee does not derive from the mere distinction of Arabica and Robusta, but depends on the meticulous attention that the grower places in every single step, from the selection of the coffee variety, from the cultivation and expression of intrinsic qualities. of the plant, from the harvesting methods and finally from the processing.
At this point, however, another link is added: the roaster. It can continue to work at its best, enhancing every value of the quality coffee purchased, or spoil everything during cooking. But we will talk about this in the next articles.
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