Earthenware is fired at kiln temperatures of approximately 1100 degrees C and pottery at 950 degrees C. They are then glazed and fired a second time at temperatures of between 50 and 100 degrees below that. This temperature is low enough for the application of glazes and underglaze colours in a wide variety of colours. The earthenware and pottery glazes used are always fritted glazes and in almost all cases contain lead.
Unlike fine stoneware the earthenware body does not become dense during firing. It remains porous. If the glaze develops a crack, moisture will penetrate into the clay.