# The Wood Firing Process

Unit: Alternative Firing Methods
Topic: Wood Firing
URL: https://claybook.studio/learn/the-wood-firing-process/

# A Multi-Day Commitment

A typical anagama or wood-burning catenary arch kiln firing takes anywhere from 24 to 72 hours or more, requires constant attention, and uses hundreds of kilograms of wood. The experience is as much about the physical ritual of stoking the fire through the night as it is about the finished pots.

## Key Stages

**Loading**: Pots are placed in the kiln with careful consideration of ash fall direction, proximity to the firebox, and the natural draft path through the kiln. Wads (small balls of refractory clay) are used under each piece instead of kiln wash, to allow ash glaze to develop all the way to the foot ring without fusing the piece to the shelf.

**Stoking**: Wood is added through the firebox at regular intervals (sometimes every few minutes during peak temperature phases). The stoker's job is to maintain a steady climbing temperature while managing the kiln atmosphere.

**Reduction**: Wood firing is naturally a reduction atmosphere because burning wood consumes oxygen. The level of reduction can be controlled by the frequency and amount of stoking.

**Cooling**: After peak temperature is reached and the firebox is closed, the kiln cools slowly (sometimes for several days). Opening too early causes thermal shock.

## What to Expect

Wood-fired pots are never uniform. Two pots placed side by side in the same firing will look completely different based on their orientation, the packing of ash, and the vagaries of flame. This variability is what makes wood-fired work so prized: every piece is a record of its own unique firing.

## Explore More

The multi-day stoking process described here is characteristic of the [anagama kiln](https://en.wikipedia.org/wiki/Anagama_kiln), where the entire firing chamber is a single tunnel built on a slope. [Bernard Leach](https://en.wikipedia.org/wiki/Bernard_Leach) built the first Japanese-style climbing kiln in the West at his pottery in St Ives, Cornwall, helping to establish wood firing as a central practice in Western studio ceramics.

## Crew Rhythm and Quality Control

Long wood firings succeed through team consistency:
*   Keep stoking intervals steady and logged.
*   Rotate roles to reduce fatigue-based mistakes.
*   Record firebox behavior, cone movement, and visual flame response each shift.

## Pro Tip

After unloading, review results as a group against the kiln map. This is the fastest way to improve placement and stoking decisions for the next firing.

## Check your understanding

### Question 1: What are "wads" used for in wood kiln loading?

- [ ] A. They hold pots upright so they don't lean during the long firing
- [x] B. They elevate pots off shelves so ash glaze can reach the foot ring without fusing to the shelf
- [ ] C. They absorb excess moisture from the clay during the early stages of firing
- [ ] D. They protect the kiln floor from ash drips

Tip: Wads are small balls of refractory clay placed under each piece. They elevate the pot off the shelf and allow ash glaze to develop all the way to the foot ring without the piece fusing to the shelf.

### Question 2: Why do two pots placed side by side in the same wood firing look completely different?

- [ ] A. Different glazes were applied to each pot before loading
- [x] B. Orientation to the firebox, ash direction, and flame paths all differ for every pot, even neighbours
- [ ] C. Temperature swings are so extreme that side-by-side pots experience different cones
- [ ] D. Side-by-side pots in a wood kiln always look nearly identical

Tip: Each pot's surface is shaped by its precise orientation to the firebox, the direction of ash accumulation, the local flame path, and countless small variations across a multi-day firing. Even small differences in placement mean the fire touches each pot differently, making every piece unique.

### Question 3: Why are steady stoking intervals critical during long wood firings?

- [ ] A. They reduce total wood consumption by exactly half
- [x] B. They stabilise temperature and atmosphere for more consistent results
- [ ] C. They prevent ash from depositing near the firebox
- [ ] D. They remove the need for slow cooling before opening

Tip: Steady stoking stabilises heat climb and atmosphere swings. Large gaps or random heavy stokes cause erratic temperature behavior and inconsistent surfaces across the load.