The processing of coffee

The Plant

The coffee plant originates from the region of Caffa in Ethiopia. Some say that the name derives from this very geographical area, others maintain that the semantic origin is the Arab word “qahwa”, which means wine. Today, the largest producer of coffee is Brazil. The plant is a member of the family Rubiaceae, coffea genus, which includes around 90 species. The three most important for economic purposes are: Coffea Arabica, Coffea Canephora (also called Robusta) and Coffea Liberica, with the latter being rarely used. The coffee plant is an evergreen, and grows in countries between the Tropic of Cancer and the Tropic of Capricorn. Plants can grow as high as 10 meters, but they are usually pruned to a height of around 2 meters to facilitate harvesting. Small white flowers grow in clusters and have an intense smell, similar to jasmine. The fruit, a drupe, is similar to a cherry, and contains two seeds or “coffee beans”.

From flower to bean

The most ancient and traditional system of coffee growing, shade-grown coffee, is used in both India and parts of Central America: coffee plants grow in the shade of other, taller types which protect them from the direct rays of the sun. In Brazil, instead, the intensive method is used: large plantations of exclusively coffee plants. In the more industrialized countries, harvesting is carried out with specific machinery, while in other countries it is carried out by hand, being therefore more difficult and slower. In speaking about manual harvesting, there are two techniques: picking, which consists of harvesting only ripe cherries one by one; and stripping, where the fruit is plucked off indifferently, even if it is not fully ripe, but separated at a later stage. The processing of coffee cherries can follow two methods: the washed, or wet, method, where the pulp of the fruit is removed mechanically and washed away with water. The beans are then left in fermentation tanks and, later, are dried and extracted from the surrounding membrane, or parchment (endocarp). The second method, the natural, or dry, method is where the cherries are dried directly in the sun. They are later hulled with specific equipment when the skin, pulp and bean are completely dry. Green coffee beans are obtained in this way, which are then sorted for defects, shape and size.

Two species for many blends: Arabica and Robusta

Caffea Arabica originated from a spontaneous mutation of a pre-existing species when the number of chromosomes doubled in the cell (from 22 to 44). With its numerous varieties (Bourbon, Catuai, Caturra, Catimor, Mundo Novo, etc), it represents, today, around 60% of world coffee production. The plant is quite delicate and requires more intense care than the Robusta species. The beans have an oval elongated shape, are green-blue and have a shallow, sinuous groove. The ideal habitat for Coffea Arabica is between 600 and 2,000 mts above sea level: the higher it grows, the better the organoleptic qualities will be.
Beans chosen from this species produce a sweet, scented coffee, with pleasant acidity, an elegant aroma and a caramel aftertaste. Coffea Robusta has half the chromosomes of Arabica, i.e. 22. Its name derives from an innate resistance to parasites and known diseases of the most grown varieties of Coffea Canephora. For this reason, it thrives in hostile environments, such as the equatorial pluvial forests. The major Robusta producing countries are in Africa and Asia, and the plant grows at an altitude of 200 to 600 mts above sea level. The green-yellow beans are round in shape, with a more pronounced, sinuous groove compared to Arabica beans. This quality gives a full-bodied coffee, with low or no acidity, roasted and chocolate aromas and a persistent aftertaste.

Roasting, blending and packaging: a science, an art

Colour, weight and volume and acquire aromatic richness. The same quality of coffee can give rise to different organoleptic characteristics depending on the methods, times and degree of roasting. With different temperatures, not only the quality of the aroma changes, but also the relationship between bitter and acid. Creating a coffee blend is a fine art which requires sensitivity and experience: every roaster has, indeed, their own secret recipes which make their coffee unique and recognizable.
Roasting, where each quality is blended in precise proportions, has three objectives:
exalt the quality of the final coffee whereby it unities the best characteristics of the different origins;
give the roaster the chance to satisfy consumers with this tangible expression of skill and capacity;
allow the roaster to always produce a product with the same organoleptic value, adjusting for the continual changes in raw materials due to natural cycles in the ecosystems where green coffee is produced.
The characteristics of any quality should not, in fact, predominate but rather blend in in a harmonic complex of pleasantness to obtain the right balance of bitter-acid-sweet and an aroma characterized by many positive notes. After blending, the coffee is ready for consumption and is packed for distribution. Packaging aims to preserve the coffee from atmospheric agents.
Different methods of packaging allow different uses so as to satisfy the various needs of the customer, which the market demands. Coffee can be packed both in beans or ground, using different techniques: vacuum, simple modified atmosphere, modified atmosphere with inert gas, and pressurized cans.

Want to discover all the uses of coffee?

The most consumed drink in the western world can be used for many ends: for physical and mental wellbeing, for body care, an ingredient in confectionary making and many, many others.