Only birch wood is used to heat the oven. Its strong and quick combustion is uniform, its flames are long and it releases few cinders. Only this wood can bring the oven to the high temperatures required (800 °C in the small fires, nearly 1300 °C in the main one. The logs of wood are 73 cm long. The oven can fire biscuit porcelain in 15–16 hours and glass or glazed porcelain in 11–12 hours. One firing requires 25 cubic metres of wood, which is burnt over 48 hours using a specialised technique in order to raise the temperature. The oven then takes between fifteen and twenty days to cool down. The wall which blocks the oven door is dismantled in order to empty the oven. A hundred pieces are fired at once, depending on their exact size.