The Two Firings: Bisque and Glaze, Explained

Almost every piece of pottery you own has been through the kiln at least twice, and the two firings do completely different jobs.

The first, the bisque firing, is relatively gentle — around 1000°C. It drives out the last chemical water from the clay and turns it from something that dissolves back into mud into something permanently ceramic, but still porous, like a plant pot. A bisque-fired pot is hard but chalky, and it drinks up glaze like a sponge, which is exactly what you want for the next step.

The second, the glaze firing, is the hot one — for our stoneware, 1280°C. This is where the glaze, which goes on as a chalky powder suspension, melts into glass and fuses to the clay body, and where the clay itself vitrifies into something dense and waterproof. It’s also where all the drama happens: colours develop, glazes run, and the occasional piece cracks or slumps. Two trips through fire, and only then is a pot finished.