Although the image of coffee plantations is often associated with huge lands that can be found in several countries, 70% of the world coffee production comes from family farms, with an area of less than 10 hectares and even generally under 5 hectares.
The time needed for a young coffee tree to start producing is 3 to 4 years. Then the shrub can live for many decades. The crown is lowered to avoid excessive development in height.
Plantations can be completely uncovered, which facilitates the organization of cultivation operations and increases fruit production by maximizing solar radiation, provided there aren’t any other limiting factors such as soil fertility, water availability, among others; but it decreases the longevity and diseases resistance of the coffee trees as it forces the plant to increase its physiological activities, as photosynthesis and perspiration. On the other hand, the plantations can be done in semi-shade (it’s called shade coffee), which best corresponds to the autoecology of the species, but reduces productivity and makes management difficult. There are numerous methods of shade cultivation, from direct planting in forest to wise combinations of shelter trees cut depending on the stage of fructification of the coffee trees or to polyculture systems. Shade plantations generally induce better biodiversity, although very variable in quality according to the systems used and in relation to the initial natural state.
2 Harvesting and preparation of grains.
When the fruits reach maturity, (from 6 to 8 months) after flowering for arabica, from 9 to 11 months for robusta, the coffee harvest can begin. Two methods are used: harvesting or stripping.
Harvesting consists of only picking manually the ripe coffee beans, in their point. It is the most expensive technique, as it forces to go through the same bush several days without interruption, but it is the way to get the best quality of coffee. Stripping consists of scraping the branch of the cherries. This method can be machined. By using this expeditive technique a heterogeneous mixture of more or less ripe cherries are collected, and it is the origin of more acidic coffees (due to fruits still green). In the Department of Caldas (Colombia), the coffee harvest takes place in the months of September, October and November. The ripe red coffee is harvested promptly to avoid the falling; the small producers, start the process of coffee transformation through the pulping of the fruits, work usually executed by using machines commonly called “Pulping Machines”, which remove the pulp from the grains and then carry out the washing and pre-selection of the grains.
The grains are then dried either with the help of the sun or by using industrial dryers. To obtain a “federation” quality coffee, the beans must be selected according to the standards indicated by the Colombian National Coffee Growers Federation.
Freshly picked coffee beans are initially processed, either by the dry method, or the wet method.
The dry process is used for Robusta coffee and much of the Arabica coffee from Peru, Brazil and Ethiopia. The grains are dried in the sun and then grounded to remove the outer layer, the dry mucilage, the yolk and the silvery shell. The milling process is carried out in large installations. Waste can serve as fuel, or as food for animals as well.
Drying is carried out on drying surfaces, where coffee cherries are raked and spread regularly. After a few days, the already dehydrated fleshy part is separated.
On the other hand, the wet process, which is used to obtain the highest quality Arabica coffee, can cause serious contamination. The ripe grains are first washed to remove the lighter ones and the garbage, they are then reduced to pulp to remove the outer layer and part of the mucilage below it. After, it is necessary to ferment the grains, newly reduced to pulp, in the respective tanks. This enzymatic process decomposes the other layers of mucilage, forming a tributary that can cause serious pollution problems, by discharging it directly into streams or rivers. After a final wash, the coffee now called “vitela” is dried in the sun or artificially. Then the coffee is peeled to remove the silvery layer and the yolk layer, producing ‘clean’ or ‘green’ coffee beans which are traded internationally.
Most of the world’s green coffee goes through some kind of washing process, including most of the top quality coffee.
Washing is applied to ripe fruits. After being harvested, the green coffee is sorted by immersion in water. The bad or immature fruits will float and the good and ripe fruits will sink. The skin of the cherry and part of the pulp is removed by pressing the grain through a submerged machine through a grate. The grain will still have a significant quantity of adhered pulp that must be removed. This is the way to get washed coffees, described as ‘own and bright’, generally less acidic and better-tasting. The technique, often mechanised, needs to have tanks and a sufficient water supply.
The wet process requires a big quantity of water and can cause serious pollution problems.
Most flow can be recycled to save water, and doing so, the enzyme content is concentrated in the water, for the pulp production process, which facilitates fermentation. The water used for the final washing can be discharged directly into the rivers, but the other tributary must pass through the filtration wells.
After drying or washing, the coffee bean is still enclosed in the core of the fruit (the endocarp): it is the coke coffee (after drying) or the patch coffee or yolk (after washing). It is necessary to sort it, in order to remove any broken, discolored or damaged beans. The selection can be machined.
The coffee can be kept protected by its own shell for some time. Some crops are even aged to improve the taste of coffee.
The last operation consists of husking mechanically the grains. The coffee is peeled to remove the thin silvery layer (the tegument) and the yolk layer, producing the ‘clean’ or ‘green’ beans which are internationally traded. The shells are recovered and used as fuel.
The dried or washed grains, then husked, are traded in the international markets
Semi-humid is a hybrid process with very limited use in Brazil and Sumatara/Celebes. The cherry is passed through a rake to remove the skin and part of the pulp, as in the wet process, but the resulting product is sun-dried and isn’t fermented or brushed.
Once the coffee has dried and becomes green coffee, it is sorted by hand or machine to remove impurities and bad or deformed beans. In addition, the coffee is also classified by size.
Some coffee beans are polished to remove the silver skin. This is done to improve the appearance of green coffee beans and to remove waste that has been produced in the roast.
Green coffee is fairly stable if stored correctly. It should be stored in transpirent containers.