Raw coffee, before being imported to Italy, undergoes processing still on the plantation.
They are essential to allow the roaster to be able to roast the coffee as best as possible, having a bean ready for “cooking.”
But how is coffee processed after harvest? What methods exist? And what taste differences do they then present in the cup?
There are 2 main methods of processing raw coffee:
The natural or dry processing method
The beans are spread out in the sun to dry, still contained within the drupes, or cherries found on the coffee plant.
At the end of the drying process they are hulled , that is, the husk and pulp are removed, extracting and preserving only the grains.
This processing makes the final coffee in cup , if well roasted and extracted, Smooth, rich and full-bodied, with sweet and fruity notes .
In fact, leaving even the pulp to dry allows time for the sugars to transmigrate within 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 more delicate, fruity and floral notes , they try to use selected and defect-free Arabica coffees. They are also picked by the method picking , that is, careful manual selection of only the drupes that are ripe at the right point.
After that, the drupes are placed in Separation tanks with clean water , for further quality control; in this way 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 , retaining only the raw grains still covered by the parchment, i.e., the thin membrane that surrounds each grain.
I grains are then placed in water tanks. where they ferment for a number of hours and/or days determined by the plantation after a series of tests and experiences.
At the end of washing, the grains always go through a sun-drying stage , as in the natural method.
It should be noted that the drying stage is one of the most delicate, as, if not well cared for, the grain over-ferments, then bringing hints of rot, mold or alcoholicity into the cup.
There are also distinctions in how the drying takes place, but we will discuss this in another article.
In addition to these two main methods, however, other variations have been added in recent years, such as semi-washed, honey process and wet hulled.
The first, the method semi-washed , is a cross between natural and washed, in that:
- Harvesting is always manual and selective as with the washed method;
- However, the sorting of drupes and their stripping is done manually or mechanically, as in the natural method;
- Finally, the grains undergo a pressure water wash, which step marks the main difference with the natural method;
- Processing is always closed with the sun-drying stage.
In the cup, a semi-washed coffee is clean and mild, with good acidity, but also good body, leaving room for sweetness.
If you would like to test for yourself the differences that different processes bring to your cup, I suggest 3 Ernani single-origins:
- Ethiopian Sidamo, a washed Arabica coffee, which a distinct acidity, good delicacy and more fruity and floral aromatic nuances DISCOVER MORE. >>
- Kalledevarapura Indian Kalledevarapura, a semi-washed Arabica coffee with good acidity, balanced by good sweetness, and an incredible aromatic range DISCOVER MORE. >>
- Brazil’s Santos Cerrado, a natural Arabica coffee with good sweetness and almost no acidity, intense and with hints of chocolate DISCOVER MORE. >>
The second however, namely theHoney process, which originated in Costa Rica, is perhaps one of the most delicate.
Honey means honey in Italian, but don’t be swayed by the name, which depends only on the gelled consistency that the pulp takes on during drying.
Being a very delicate and complicated method, it is used primarily for coffees of a certain quality, harvested with careful manual selection .
It follows the spoliation , but leaving a layer of mucilage, i.e. pulp, on the kernels. It, as with the natural method, allows a migration of sugars into the grain, then making the final cup sweet and intensely aromatic.
Then depending on how much mucilage is left on the grains there is a division of the honey method into Black if 100% is present, Red if 75% is left, Yellow if 50% is left and finally Golden or White if between 25% and 10% is left.
Drying always takes place. in the sun , but takes longer.
The risk of over-fermentation, resulting in grain damage is very high, so it is complicated and delicate, and its use requires great experience and attention from growers.
And finally we come to the method Wet Hulled . It is to date little used, as it is still a novelty, because of its peculiar workmanship.
There is always meticulous, manual harvesting of the grains and plucking.
At this point the grains in parchment, undergo a rapid fermentation in plastic sheets , and are then washed.
After that they are made sun drying , but only partially, up to 50 percent .
It is the only method that presents the parchment removal before the end of total drying. In fact, when the grain is 25 to 30 percent moist, the last thin layer, referred to as parchment as mentioned above, is also removed, and only then is the drying process finished.
In this case, the final coffee in the cup results sweet and complex, with a great personality .
Another method, which is very modern and therefore still very little used, is the Carbonation , in which the grains are fermented in barrels , as is the case with wine, with added CO2 , or carbon dioxide.
With this article we have concluded the summary analysis of the cycle of processing that takes place on the plantation, before the beans are imported and arrive at the roaster, ready for “cooking.”
From this it can be seen 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 farmer pays to each and every step, the selection of the coffee variety, the cultivation and expression of the inherent qualities of the plant, the harvesting methods and finally the processing.
At this point, however, another link is added: the roaster. It can continue to work at its best, enhancing every merit of the quality coffee purchased, or ruin everything in the cooking process. But this will be discussed in future articles.