What heat earthenware can stand on

Zlakusa pottery takes an electric ring, an open fire and an oven, and gas or a ceramic hob over a thick metal plate. On induction it works only with a metal adapter, because an induction hob heats metal rather than the vessel. One rule holds for every source: the heat comes up gradually, from cold.

Electric ring

The simplest case. The ring should be wider than the base, or at least as wide — a narrower one heats a single spot, and the difference between that spot and the rest of the base is exactly what breaks a wall. Start at the lowest setting and raise it after five to ten minutes. An empty vessel is not left on a lit ring.

Ceramic hob

Over a metal plate, not directly. There are two reasons. The base of an unglazed vessel is rough and leaves marks on glass-ceramic that cannot be lifted afterwards, and such a hob heats in short bursts at full power, so the vessel above it warms in jerks rather than evenly. A metal plate in between solves both: it spreads the heat and keeps the rough base off the glass.

Induction

An induction hob does not heat what sits on it — it induces eddy currents in the base of the vessel, which then heats through its own resistance. That needs ferromagnetic metal. Clay is not metal and does not respond at all: the hob usually fails to detect the vessel and reports an error.

The answer is a steel adapter — a disc that goes on the hob with the vessel on top. It works, but it brings its own risk: the disc heats very fast, and the vessel sits on an already fierce surface. So on induction you start at the lowest setting, stay there longer than you would expect, and only then raise it.

Gas

A flame strikes a narrow zone of the base, which is spot heating in its purest form. A thick metal plate goes between the flame and the vessel, three to four millimetres — a heat diffuser, sold under that name. Set the flame so it stays under the base and does not lick up the side: a wall heated from outside while cold inside will crack.

Oven

The vessel always goes into a cold oven and comes up with it — never into one already hot. Cooking itself rarely goes above 200—220 °C; 250 °C belongs to the empty seasoning bake, done once, at preparation. When the food is ready, the hot vessel is not set down on a stone worktop or in the sink, but on a board or a cloth, and left to cool on its own.

A fan oven is not a problem in itself, but it dries the surface faster, so times shorten. The top element working alone at maximum is a poor idea: it heats the upper rim while the base stays cold.

Open fire and embers

This is the heat the vessel was made for, and even it asks for gradualness. The vessel is held twenty to thirty centimetres from the embers until it has warmed through its whole height, and only then moved closer. Good embers beat a live flame: they heat evenly and do not strike one spot. A kettle hung above the fire is lowered by stages, for the same reason.

What is never done

• A vessel straight from the fridge into an oven or onto a ring
• A vessel into an oven that is already hot
• Cold liquid into a hot vessel, or hot into a cold one
• A hot vessel set on stone, metal, a wet cloth or in the sink
• A flame or ring narrower than the base, sending heat to one spot
• An empty vessel on fierce heat, outside the controlled seasoning bake

Electric ring

yes — ring wider than the base, starting at the lowest setting

Ceramic hob

yes, but over a metal plate — never directly on the glass

Induction

only with a steel adapter; clay does not work on induction alone

Gas

over a heat diffuser, 3—4 mm, flame kept under the base

Oven

yes — always from cold; cooking usually up to 200—220 °C

Open fire and embers

yes — 20—30 cm from the embers first, then closer