High fire refers to firing pottery to about cone 9 to 10, roughly 1280 to 1300 °C, the traditional range for stoneware and porcelain. It produces very dense, durable ware and is often done in gas kilns with reduction.
What Is High Fire?
Potters divide firing temperatures into low fire, mid fire and high fire. High fire is where classic stoneware and porcelain traditions sit, with effects such as celadon, tenmoku, shino and wood-fired surfaces. Orton lists cone 10 at about 1285 °C when fired at 60 °C an hour in the final stage.
At these temperatures clay bodies become highly vitrified, glazes are durable and often subtle, and the clay itself shows through as warm flashing in reduction. Many electric kilns can reach cone 10, but firing that hot every time wears out elements and costs much more electricity than cone 6.
That is why many studios, especially with electric kilns, now fire to mid fire instead. Cone 10 clays and glazes shouldn’t be fired at cone 6, where they stay underfired, and mid-fire clays shouldn’t go to cone 10, where they can bloat or slump. Always match the clay and glaze to the kiln’s firing.
This pottery glossary entry from Le Studio Art Space is general educational content. Always follow the clay, glaze and kiln makers’ data for your own materials and equipment.