Bringing a cup of steaming coffee to the lips is a common gesture in most of the world, but only few people wonder about the origin of the drink, its history and its social meaning.

Many legends refer to the origin of coffee. Everybody knows the legend coming from the Chehodet Monastery in Yemen, according to which one of the monk that, having being told by a shepherd named Kaldi that his goats and his camels were "lively" also during the night if eating certain berries, prepared a drink with these berries with the intent to stay awake to pray longer.

In the classification system of the vegetable kingdom created by the Swedish botanist Carl Linneo, coffee was classified in the family of "rubiacee", that gathers 4500 varieties among which 60 species belong to the coffee group. Of the 60 coffee plants species, only 25 are the most commercial for the fruits but only the first four of them have a prominent position in the trade of coffee beans: Coffea Arabica, Coffea Robusta, Coffea Liberica and Coffea Excelsa.