The dragon kiln is characterised by its “head”, “body”, and “tail” built upon a slope or hill, with the head lower than the tail. The “head” or firebox is where firewood is fed. First, firewood is burned in the firebox for 12–20 hours to dry the entire kiln. Often, there is a kiln-god altar located above it. Praying to the kiln god before the firing is a ritual still practised today.
The “body” of the kiln is where the pottery is placed. The pieces are carefully arranged in chambers along the length of the kiln according to their grades. They are stacked on top of each other or packed neatly on shelves, often separated by clay wadding and cockle shells. Pottery that can withstand higher temperatures are placed nearer the “head”. Temperatures can go up to 1,300°C at the “head” and 1,000°C at the “tail”.
The entrances to the kilns are sealed during firing, but there are “eyes” or stoke holes located along the “body” where firewood is fed. The fire can also be observed through these holes. An experienced potter can judge the temperatures in the kiln chambers based on the colours of the flames. These days, temperature sensors and pyrometric cones aid this process. Rising hot air pushes smoke out through the chimney at the “tail”.
Between 5,000 kg and 10,000 kg of firewood is fed to the kiln. The whole firing process can take three to four days, and the kiln is then left to cool for a week.
Potters are drawn to dragon kilns over their modern-day counterparts, the gas and electric kilns, because of the natural ash glaze that cannot be achieved by modern methods. This special glaze comes from the fly ash and volatile salts reaction, fusing and melting into the clay in the process of wood-firing. The unpredictable effects on colour and texture are what draws potters to dragon kiln pottery.