What Bisque Firing Really Does

Before glaze, before colour, before your pot can hold water — it needs to be bisque fired.
This first firing might seem like a technicality, but it’s one of the most important steps in the entire ceramics process.

Let’s break it down.

What Is Bisque Firing?

Bisque firing is the first firing that clay undergoes after it has dried completely (aka bone dry).
It transforms the clay from greenware (fragile and water-soluble) into ceramic — strong, porous, and ready for glaze.

Why Not Just Glaze Fire from the Start?

Great question. Here's why:

• Raw clay is too delicate to handle once dry.

• It can’t hold glaze properly — it sloughs off or soaks in unevenly.

• It still contains organic materials and chemically bound water that need to burn out slowly.

Bisquing prepares the piece for its final form.

What Actually Happens During Bisque?

• Physical water evaporates under 100°C

• Chemical water burns off between 350–600°C

• Carbon, sulfur, and other organics combust

• The clay starts to sinter — particles bond, making the piece rigid but still absorbent

How Hot is Bisque Firing?

Most studios bisque to:

• Cone 06–04 (around 1000–1060°C)

• Hot enough to strengthen the piece

• Cool enough to leave it porous enough for glaze to soak in

What Happens If You Under- or Over-Bisque?

• Under-fired bisque is too soft and dusty — glaze doesn’t stick well.

• Over-fired bisque is too hard and won’t absorb glaze properly.

Like Goldilocks, we aim for just right.

Pro Tips for a Good Bisque:

• Fire slow — especially below 200°C to avoid cracks from steam.

• Don’t rush drying — bisque should never go in damp.

• Fire on a full shelf — avoid single pieces that heat unevenly.

Bisque firing is the quiet, unseen stage that makes everything else possible.
It’s the bridge between shaping and finishing — and when done well, it sets you up for success in glaze, strength, and beauty.