The Alchemy of Wood-Fired Glazing

There's a moment, about 36 hours into a firing, when you stop being in charge.

The kiln has its own ideas by then. The flame path has chosen its route through the stacked pots. Ash is settling on shoulders and rims in ways no glaze recipe could predict. You're still feeding wood into the firebox every eight minutes — you haven't slept properly in two days — but the truth is, the kiln is making decisions you can only witness.

This is what makes wood-firing different from every other way of finishing ceramics. In an electric kiln, you set a temperature and a timer. The results are predictable, repeatable, controllable. In a wood-fired kiln, the fire itself becomes a glaze material. Ash lands on raw clay and melts into glass at 2,300°F. Where the ash lands thickest, the glaze pools deepest — amber, olive, sometimes a flash of copper blue that nobody planned.

The variables you can't control

The type of wood matters. Oak burns slow and hot. Pine burns fast with a lot of ash. We use a mix — mostly eucalyptus from a friend's property in Tilden Park, supplemented with oak scraps from a furniture maker in Emeryville. Each species produces different mineral content in its ash, which means different colors on the finished piece.

But it's not just the wood. It's the placement of each pot in the kiln. Pieces near the firebox get hammered with flame and ash — they come out dramatic, with heavy "flashing" marks where the fire kissed the clay. Pieces in the back are more subtle, with thin ash deposits that create a soft, matte surface that feels like touching stone.

We spend an entire day loading the kiln. Every piece placed deliberately, angled to catch the flame path we think will develop. But "think" is the operative word. The kiln always surprises us.

What comes out

After 48 hours of firing, we seal the kiln and wait five days for it to cool. Opening day is genuinely exciting — two months of throwing, trimming, and bisque-firing all comes down to what the fire decided to do.

Some pieces emerge transformed — a simple bowl becomes something almost geological, with layers of color built up by ash deposits. Others are quieter, with just a blush of warmth where the flame touched them. Every piece is unique. Not in the marketing-copy sense of the word — in the literal sense that no two surfaces in the entire load will look the same.

This is why we do it this way. Not because it's efficient (it isn't). Not because it's easy (it really isn't). But because the fire adds something that no human hand can. It adds chance, and time, and the particular chemistry of this wood, this clay, this day.

Every piece that leaves our studio carries the memory of that 48-hour conversation between fire and earth. You can feel it when you hold one. That's the alchemy.