finish_glaze_ash

Ash glaze

glaze · translucent · wood-ash glaze, natural ash, anagama glaze

Glaze made from the ash of burned wood, applied directly or formed on the pot during long wood-firings as ash settles from the flame. Each ash variety (oak, pine, rice straw, bamboo) shifts the color and surface character. Reads as warm earth-tones, deep glassy pools, the surface of a Bizen or anagama pot.

Wood ash contains 30–60% silica + 5–15% alumina + 30–60% mixed alkali / alkaline-earth fluxes (CaO, K₂O, Na₂O, MgO) — a near-complete glaze on its own. Applied wet (slurry of washed ash + water + a clay bond) or formed in the kiln during 4–10 day wood-firings as ash settles on horizontal surfaces and runs as it melts. Cone 10–12 (1280–1320 °C). Color sequence iron-driven: tan / warm orange where thin, deep brown / black where pooled, blue-green or yellow flashing in reduction zones. Each tree species produces a different chemistry — pine is silica-rich, oak is calcium-rich, rice straw is silica-and-flux-rich.

character — warm earth-tones, glassy pools, ash-run rivulets, irregular kiln-driven flashing.

Finish properties

  • leveltranslucent
  • subcategorywood-ash flux glaze
  • applies toceramic
Pairs with materials

Second life

reversibilityzero — fired ceramic glaze cannot be unfired; the glassy layer is permanent. Damaged or chipped glaze can be re-glazed and re-fired with chemistry-compatibility planning.
blocks substrate recyclingno
renewabilitymoderate — re-glazing and re-firing is a studio-renewability path for damaged ceramic; the constraint is the original-firing temperature (the re-glaze must fire below the original).

Robin Hopper *The Ceramic Spectrum* (Krause, 2nd ed.); Daniel Rhodes *Clay and Glazes for the Potter*.