Coffee goes through a difficult way from infructescence up to the moment when hands of the expert prepare an excellent drink out of it. Quality of coffee beans depends not only on a tree kind or plantation conditions where they are grown up on but also sufficiently from thoroughness of processing at all stages.
Fruits of a coffee tree are ripening 6-8 months and are set throughout a year. Therefore it is possible to gather coffee with the machinery only in Brazil where owing to special conditions the crop ripens approximately at one and the same time. Thus, fruits of coffee trees are often gathered manually or shaken dried up on a laying (as in Yemen, for example).
The crop undergoes the pre-processing directly on a plantation. Coffee quality depends not only on a botanical grade of a coffee tree, soil and other conditions but also on the way of its gathering and processing. It is important to collect only mature fruits. Unripe beans are tasteless. On the other hand, being ignorant it is possible "make ducks and drakes" of perfectly ripe fruits as they should be processed properly at once, in other way the crop will deteriorate, grow mouldy and turn rancid. The gathered coffee is transported on donkeys, carts or small trucks on farms where fruits, first of all, either are sifted or washed out by water to remove leaves, unripe fruits, stones, sand and other impurity. But it’s only preliminary clearing; it, of course, doesn’t have anything in common with the procedure of processing of the gathered coffee fruits in a dry or wet way.
More ancient way of processing is dry. It is used, first of all, in Brazil and in the Western Africa. The dry method is used in possessing of 60 % of a world crop of coffee (almost all world crop of Robusta coffee). It is a very ancient way when the unripe and overripe berries are preliminary sorted from garbage, then ripe fruits of coffee are laid in a thin layer (3 - 5 cm) on a large paved or concrete surface and are left under the sun until complete dry out that, certainly, has an impacts on beans giving them original relish and sometimes is negatively reflected in their quality.
In order that the drying process to be realized in regular intervals coffee grains should be overturned several times a day. This stage of processing usually takes some weeks. To protect coffee beans from heat, rain and morning dew, the platforms with coffee are covered with awnings overnight. In some climatic zones a part of the crop is dried by means of special hot air machines. Thus time of dry processing is reduced to two-four days.
During drying of coffee beans are fermenting and ripening for good and all, get more perfect shades of taste and smell due to chemical reactions going on in an external layer.
In 4 weeks all fruit consisting of an external thin skin, pulp, a parchment thin skin, a silvery thin skin and a coffee bean dries up so that the water maintenance in it decreases to 13 %. Further beans are put into bags and stored for some more weeks to lower humidity. After that the dried up external cover of a fruit peel and separate green coffee grains. Then the best beans are selected manually or at the modern enterprises in the electronic way.
The way of dry clearing is more favourable in the economic way, but quality of coffee beans is worse than at processing by other methods.
Wet processing represents more difficult and mechanised process. Almost all high-quality grades of coffee are processed by such method. It concerns the majority of Central American coffee grades, the Colombian and Mexican grades and also coffee from Kenya and Tanzania. Such coffee is also called "washed" or «milds». Wet processing should be carried out first days after harvesting and is better at the first 12 hours.
Well ripened fruits are gathered and are poured into the big drums with a rough surface inside that are rotated with different speed with a constant strong stream of water. Barrels delete almost all of the pulp but a little part of it remaines, therefore from drums coffee fruits are unloaded in coppers, and then put into heaps or holes which have been laid out by tiles, and there they are fermented.
When the rests of pulp have softened after fermentation, they are absolutely easy to be washed off by flowing water. Washed coffee beans are laid out on equal platforms by tiles or stamped by clay and 3-4 hours per day are dried on the sun by constant stirring. It is very important stage in coffee manufacture. Now coffee beans as if "accumulate strengths", get fermented, get their flavouring qualities and aromatic properties.
Too fast drying, as well as long, spoils them. This process usually lasts about a day. Properly dried up coffee beans are put into the machinery for removal of seed cover and internal peel. The refined beans are sorted by the size and selected manually or by means of the special electronic equipment.
Recently the so-called “semidry” technologies have been adopted for the sake of reducing the expense of water almost on 90 %.
Irrespective of a way of processing the next stage is manual sorting of coffee grains according to the size for maintenance of roasting evenness. It is easy to understand how hard and wearisome this work is. If the process of sorting is not realized, fine grains will burn out and large ones - remain in a half-baked condition.
Coffee is usually transported by the sea. The most convenient form of packing for this purpose is bag. The weight of the packed bags differs depending on the country-manufacturer. As a rule, it is within 60-70 kg. For statistics average accepted weight of one bag equal to 60 kg.
Green coffee beans can be stored for more or less long time. However if a period of storage is too long beans become colourless, white and coffee loses the flavouring and aromatic properties. Light and moisture affects coffee beans the worst.
Green beans are considered to be stored within two years. Certainly, much depends on storage conditions. And properties of some grades of Brazilian coffee, according to experts, at storage from three to five years even improve.