bonfiring

Bonfiring is the practice of firing clay vessels in an open fire rather than in a kiln. The pottery is stacked among combustible materials, wood or other fuel is piled around and over it, and the whole mass is ignited. The fire burns freely to the atmosphere, reaching temperatures typically between 900 and 1200 degrees Celsius, depending on fuel type, airflow, and load density. This method produces functional ware and ornamental pieces, though the results are less predictable and generally lower-fired than kiln ceramics.

The process requires careful arrangement of the load. Pots are positioned in layers, separated by fuel so flames and hot gases circulate around all surfaces. Sawdust, wood chips, straw, or dung may be used alongside logs to control burn rate and temperature gradient. The fire must sustain itself for several hours. Once lit, little active control is possible; success depends on load preparation, fuel moisture, weather conditions, and operator experience.

Results vary widely. Uncontrolled oxidation produces red and buff wares. Local reduction (oxygen starvation in pockets of the fire) can create gray or black surfaces. Ash settling on pots during firing leaves natural glaze and surface texture. Some potters use this unpredictability as an aesthetic feature; others see it as a limitation. Pieces may be porous or brittle if the fire cools too quickly or unevenly.

Bonfiring remains common in hand-pottery traditions and archaeological reconstruction. It requires minimal infrastructure and no fuel beyond what a location can supply. The method is also used for low-temperature bisque firing of unfired clay before high-fire kiln work, though this use is less common in industrial ceramics. Large-scale pottery production abandoned open-fire methods centuries ago in favor of updraft and downdraft kilns that offer repeatability and efficiency.

The term itself preserves an older vocabulary: the word "bonfire" derives from "bone-fire," referring to fires that burned bone or other scrap fuels. In ceramics, bonfiring carries no such technical meaning today, but the name reflects its roots in utility rather than specialization. It remains a marker of low-technology firing practice, valued most where control is less important than accessibility.