Botijo

[5][6] The botijo, or water jar, is a typical element of culture in many parts of Spain and may vary in shape and color.

[7] The botijo has a wide belly and one or more mouths where it is filled and one or more outputs, called pitón or pitorro (in Spanish), to drink from.

[9] The búcaro de Indias is a special type, made of fragrant clay from Mexico, that was prized in Europe.

...because of the porous nature of the clay jar, which is unglazed, the water within will slowly seep out through the pores, and the warm air outside causes evaporation.

This circulation and evaporation keeps the walls of the jar cool, and the water inside lowers in temperature, and becomes excellent for drinking.