Coffee Growing

 

1 Cultivation

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Even though the popular image of coffee plantations is often associated with enormous plots of land in various countries, about 70% of the world's coffee production comes from small family holdings less than 10 hectares in size, and normally less than five hectares.

The time needed for a young coffee plant to start producing beans is between 3 and 4 years. From then on the plant can live for a number of decades. The canopy is pruned to avoid the plant growing too tall.

Planting can be done in the open air. This helps to organise the cultivation process whilst increasing fruit production by making the most of the available sunlight, assuming there aren't other limiting factors such as soil fertility, or water availability, amongst others, to contend with. However, on the downside it reduces the lifespan and resistance to disease because it forces the coffee plants to increase their physiological activities, like photosynthesis and transpiration. On the other hand, planting can be done in semi-shade (known as shaded coffee), which corresponds best to the species' own ecology, although it reduces productivity and complicates the work. There are a number of different methods to cultivate in the shade, from planting directly in the forest to clever combinations of refuge trees that are felled according to the flowering of the coffee plants and there are even systems of polycultivation. Whilst generally helping to provide greater bio-diversity, shaded plantations can be very variable in quality, depending on the cultivation system employed and their initial natural state.

 

2 Cosecha y preparación de los granos

cafetales2Harvest can begin after flowering when the fruit ripens (from 6 to 8 months) on the Arabica, and after 9 to 11 months on the Robusta. Two methods of harvesting are used: by hand or by destemming.

Harvesting by hand consists of picking only those fruit that have ripened to just the right point. It is the most expensive method as it involves returning to pick from the same bush various times for several days in order to get the best quality coffee. The destemming method involves plucking the fruit from the branch. This method can be mechanised. A heterogenuous mix of more or less ripe fruit is harvested using this method, and it is also the origin of the more acidic coffees (because there is fruit that is still green). In the Department of Caldas (Colombia), the coffee harvest takes place during the months of September, October and November. The ripe coffee, which is red in colour, is promptly picked in order to avoid it falling off the bush; the small holders then begin the coffee transformation process by depulping the fruit, a task which is generally performed using machines known as "depulpers", which extract the pulp from the fruit before being washed and pre-selected. Later on the grains are dried in the sun or with industrial driers. To obtain a "federation" quality coffee the grains have to be selected according to the standards set by the National Federation of Colombian Coffee Producers.

Initially, the recently picked coffee berries are processed, either by the dry method or by the wet one.

Dry method

The dry method is used for Robusta coffee and for a majority of Arabica coffee from Peru, Brazil and Ethiopia. The berries are dried in the sun and later ground to eliminate the outside layer, the mucilage, the vellum, and the shiny skin. The grinding process takes place in large installations. The waste products can be used as fuel or as animal feed. Drying occurs on raised drying beds, where the coffee berries are raked out and turned over on a regular basis. After a few days the meaty part, which is already dehydrated, is separated.

cafetales1Wet method

On the other hand, the wet method, which is used to obtain the highest quality Arabica coffee, can cause serious pollution. The ripe berries are first washed to get rid of the detritus and the unwanted grains, then they are reduced to a pulp in order to extract the outer layer and part of the mucilage just underneath it. Immediately afterwards, these pulped grains have to be fermented in their respective tanks. This enzymatic process decomposes the other layers of the mucilage but the resulting water outlets cause serious pollution to surrounding rivers and streams. Following a final wash, the coffee, now known as "vellum", is dried artificially or in the sun. Later on the coffee is dehusked to get rid of the shiny outside layer and the vellum, producing a "clean" or "green" coffee bean that is sold throughout the world.

The majority of the world's green coffee, including most of the superior quality coffee, goes through some kind of washing process.

A wash is given to well ripened fruit. After being picked, the green coffee is classified by immersing it into water. The bad fruit or the unripened fruit float to the surface whilst the good and ripe fruit sink. The skin of the fruit and part of the pulp is eliminated by pressing the berries through a grill using a submerged machine. The berries still retain plenty of pulp which needs to be removed. It is in this way that washed coffees are produced. They are generally less acidic and better tasting and often described as "personal and brilliant". The technique, which is often mechanised, requires vats and an adequate water supply.

cafetales3The wet method requires alot of water and can provoke serious pollution problems. To economise on water most of it can be recycled, which helps to concentrate the content of enzymes in the water. This enzyme-rich water can then be used in pulp production by facilitating the fermentation process.

Although the water used in the final wash can return to the river, the other water outlets must pass through the filtering wells.

After the drying and washing process, the coffee grain is still enclosed in the heart of the fruit (the endocarpio): this is called husk coffee (after drying) or patch or vellum coffee (after washing). It is necessary to classify it, with the aim of eliminating any decomposed, discoloured or damaged coffee. The sorting can be done by machine.

Coffee which is protected by its own husk can be conserved for a certain amount of time. Some harvests are even aged to improve the taste of the coffee.

The final stage of preparation consists of mechanically peeling the grains. The coffee is peeled to get rid of the fine shiny layer (the tegumentum) and the layer of vellum, thereby producing "clean" or "green" coffee grains sold worldwide. The husks are are recuperated and used as fuel.

Following peeling the dried or washed grains are sold commercially on the international market.

Semi-wet

The semi-wet process is a hybrid technique used in Brazil and Sumatra/Célebes. The fruit is passed through a grate to remove the skin and part of the pulp just like in the wet process but the resulting product is dried in the sun and not fermented nor cleaned.

Once the coffee has been dried and becomes green coffee it is sorted by hand or by machine removing bad, deformed grains and any other impurities, as well as classifying it into different sizes.

 

3 Polishing

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Some coffee grains are polished in order to remove the shiny skin. This is also done to improve the appearance of the green coffee and to remove the residues produced in roasting.

 

4 Storage

Green coffee is quite stable if stored correctly. It should be kept in containers that transpire.