How Coffee Beans Are Processed?

Before reaching your coffee maker, the coffee goes through different phases. We tell you, step by step, how coffee processing is carried out.

Collection

The first step in coffee processing is to collect the fruit from the bush from which the coffee comes. This is done when cherries or berries acquire a reddish or yellowish color and can be carried out in 3 ways:

Manual: berry to berry, choosing only ripe fruits.

Scraping or de-stemming: this method is usually used when most cherries are ripe. By sweeping the branches of the coffee tree, both ripe and green fruits are removed, which fall to the ground or on canvases. Next, the impurities that have fallen and the green grains are separated by venting, which produce a more acidic flavor.

Mechanics: this is the methodology most used by large coffee producers and consists of using large machines to remove berries from trees. Some of these machines make the trunk vibrate so that the fruits fall to the ground. Others have built-in brushes that extract the fruits of the tree, it is the least selective method of all.

Pulping the fruit

At the same time that the berries are harvested, the residues of the crop are eliminated, the layers that surround the beans are removed and green coffee is obtained (a term that designates the coffee after being processed and before roasting). This procedure is known as pulping.

To carry out this part of the coffee processing, there are several methods and, depending on the one used, the cost of coffee and its quality will vary.

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a) Natural coffee processing: dry method

It is the oldest and simplest, in addition to requiring little machinery.

It is used for 90% of Arabica coffee produced in Brazil, for some arabica from India and Ecuador, and for most coffee from Haiti, Paraguay, and Ethiopia. Almost all robusta coffees are processed with this method, which is not very practical for areas whose atmospheric humidity is too high or where it rains frequently during harvest.

Cafes processed in this way have low acidity and exotic flavors. Also, it is common to find intense wine and fruity flavors.

The dry method consists of the following stages:

  • Classification and cleaning: during this phase of coffee processing, green fruits are discarded, as well as those that are too ripe or damaged. Then, the impurities (dirt, branches, leaves…) are removed by screening or flotation.
  • Drying: coffee berries are exposed to the sun and are raked or turned manually to dry evenly and reach a maximum final humidity of 12.5%. Although this phase usually lasts about 4 weeks, in some larger coffee plantations drying machines are used to accelerate the process. Drying is the most significant step of the process since it influences the end feature of green coffee. Coffee that is too dry is characterized by the fact that the beans are brittle and therefore defective; while coffee that is too wet will be prone to rapid deterioration by fungi and bacteria.
  • Shelling: dried berries or cherries are put in bulk in specific silos until the moment they will get to the mill. Once there, the shelling machine removes all the external covers of dried cherries from one, and then they are separated, sorted and put in sacks.
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b) Natural wet process (washed coffee)

This approach requires the use of specific equipment and considerable amounts of water. Coffee obtained in this way is considered of better quality and is usually more expensive.

As a general rule, it is used for all arabica coffees, with the difference of that manufactured in Brazil and in the producing countries of this variety mentioned above and that use the wet technique. It is rarely used for robusta.

Washed coffees are characterized by having more fruity and floral flavors, and more intense acidity.

The wet technique is performed as follows:

  • Cleaning and selection: first, the cherries are washed using tanks filled with running water and the ripe cherries of those that are not and the large ones are separated by sieves.
  • Shelling: This process is the main difference between one method and another. In a wet way, the pulping is performed by a tool that presses the fruits within movable and fixed plates, adjusted so that the grains are not damaged. The skin and flesh of the berries are on one surface and the grains, coated with parchment, on the other. Shelling should be done just after harvesting to prevent the fruit from deteriorating and affecting the quality of the grain.
  • Screening: the pulped grains pass through vibrating screens that separate them from the berries that have been left without pulping, from those that have an imperfect shape and from the large pieces of pulp that may have remained attached.
  • Washing and separation: the separated pulped grains are passed through channels where they are washed with water and separated again by floating them.
  • Fermentation: coffee beans are placed in containers for 24-36 hours and in which the parchment that wraps coffee beans decomposes under the influence of natural enzymes and is carried away by water. If this phase of coffee processing is not carefully monitored, it can acquire a bitter and undesirable taste.
  • Washing: again, in tanks or special washing machines.
  • Drying: this process aims to leave the coffee at a maximum humidity of 12.5% ​​and can be done in the sun or with the help of a mechanical dryer. It is important to be careful so that the drying is satisfactory. Otherwise, the coffee quality will be affected.
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Packaging and transport

Coffee is classified according to its size and defects number and is packaged in sacks to make storage and transport easier, although containers are increasingly used.

Roasting and packaging

This is the phase during which the coffee bean ends up taking the necessary form and, above all, its flavor.

This part of the coffee processing is the only one that is usually done in the country of consumption. Toasters mix different varieties and toast them to the taste of local consumers.

Finally, roasters vacuum package freshly roasted coffee and, sometimes, even already ground.