Coffee is defined as the drink (infusion) that is obtained from the ground and roasted beans of the coffee plant.
Coffee cultivation is widely spread in tropical and subtropical countries.
There are two main varities of coffee: Arabic coffee and Robust coffee.
Arabic coffee has been cultivated since the oldest days. It is very fine and aromatic, and needs a cooler atmosphere. Its cultivation is more delicate, less productive and it is kept for the high mountains between 900 and 2000 metres. It comes originally from Ethiopia.
Robust coffee offers a richer drink in caffeine. It is stronger and sharper. This kind of coffee can adapt itself to flat lands, with higher yield. It comes originally from Congo, and it is rougher than the Arabic (that is why it is called Robust coffee).  
Coffee arrived to Europe in the year 1.600 approximately, thank to the venetian merchants.

Coffee roasting.
Once in their destination, coffee beans are roasted, which allows the aroma and dark colour to be developed. In some countries, roasting is made by adding to the beans up to 15% of sugar. In this case, the process is called differently in spanish: torrefacción, and the resulting coffee has a more vigorous flavour, and its beans has an oily and shiny appereance due to the caramel over it.
With the roasting, coffee beans increase their size. When the heat application is starting, coffee beans colour turn from green to yellow, and then to brown cinnamon. At this moment is when they loose their humidity. When the inside reaches 200ºC degrees, the oils of the coffe beans go out. In general, the more oil there is, the more flavour coffee has.  
During the roasting, coffee beans crack in a similar way to popcorn when they explode under the heat. There are two explosion moments that are used as signs of the roasting level reached.
Roasting levels: blonde, cinnamon, medium, monk´s clothes, brown, dark brown.
Coffe beans turn darker and release even more oil until roasting is finished, and they are moved away from the heat source.

Grinding and Infusion
Grinding thickness point has an important impact in the coffee drink production process, and it is critical to know how to combine the consistency of coffee refinement level with the production method so that a top-quality flavour can be extracted from the roasted coffee beans. Over-ground coffee beans will be very exposed to the hot water and it will cause a bitter and sharp taste. On the other extreme, if coffee beans are little ground, and the particles are very thick, final coffee drink will be weak, watery and flavourless.  
Deterioration rate increase when coffee is ground, as a result of the bigger superficial area exposed to oxygen. Due to the bigger coffee consumption as a gourmet drink, grinding coffee beans at home just before drinking coffee has become very popular, and there are a lot of electrical appliances that allow it.
Coffee must be kept in a dry, cool, dark and sealed place.