The shape and function of the kaiku, together with the technique used to make it, make it one of the most characteristic of Basque items. It is made from a single piece of wood (generally birch) which is cut and hollowed out on an inclined axis. It is designed to fulfil three functions: to catch the milk when sheep are being milked; to carry or pour the milk easily, using the horizontal grip at the top and the vertical handle shaft at the back; and as a recipient for boiling the milk directly, by adding some ophite stones previously heated on an open fire.
Alongside the kaikus are a beaker and two measuring cups. The beaker is called an opor in Basque. It is made from a single piece of wood and tapers slightly in a truncated cone shape. It is generally used for drinking milk-based soups and corn pancakes (talo) or corn bread (arto).
The two kaikus are from the Provincial Government of Gipuzkoa’s J. Gorriti collection. The opor is from Igantzi (Navarre). The measuring cups are from the Mendiola farmhouse (Amezketa, Gipuzkoa). The last three pieces come from the Museo San Telmo collections.
"Leizaola, Fermín de. Gipuzkoako artzaintza. [Donostia = San Sebastián] : Gipuzkoako Foru Aldundia, Kultura, Euskera, Gazteria eta Kirol Departamentua, 1999. 51
Bildumen Gida = Guía de Colecciones. Bilbao: Euskal Museoa = Museo Vasco, 2002. 234"