Masonry oven India, tandoors are traditional clay ovens, although these days modern electrically fired tandoors are available. The open-topped tandoor is a transitional design between the earth oven and the Roman-plan masonry oven. In the precolumbian Americas, similar ovens were often made of clay or adobe and are now referred to by the Spanish term "horno" (meaning "oven"). Horns are also traditional in the American Southwest. The traditional direct-fired masonry design is often called a "Roman" or "black" oven and dates in Western culture to at least the Roman Republic. It is known as a black oven because the fire generates soot
Kenya Ceramic Jiko remain slightly porous when temperatures reach 1150 °C; the clay should not warp or change shape when fired at 1250 °C. When the clay is fired up, it should turn to a light pink to white colour, and, to reduce the likelihood of cracking, it should shrink less than 8% after being fired. Clay which meets all the above standards is generally referred to as a "fireclay". To produce the Kenya Ceramic Jiko, two types of skilled labour are needed, a metalworker, and a clay worker. Other than a hammer, all other tools needed to manufacture the Kenya Ceramic Jiko