Induction-ready: what to check before you buy

"Induction compatible" appears on a great deal of cookware, and it covers a wide range of actual performance. Here is how to check for yourself.

Test one: the magnet

Take a fridge magnet to the shop.

• Sticks firmly to the base? It will work on induction.
• Slides off or holds weakly? It will not, or it will work poorly.

Then test the side wall as well. This distinguishes two quite different constructions:

• Magnetic everywhere — the whole body is a ferritic steel, magnetic throughout. This is our Krome 16+ range.
• Magnetic only on the base — a non-magnetic austenitic body with a magnetic disc bonded underneath.

Both work. The second introduces a bonded joint between dissimilar metals that is repeatedly heated and cooled, and over years of commercial service that interface is a place failure can begin.

Test two: flatness

Induction coupling falls off with distance, so the base must sit flat against the glass.

Put the vessel on a genuinely flat surface and look at it from eye level. Any daylight underneath, or any rocking, means an air gap and reduced efficiency.

Be aware that some vessels are flat cold and become slightly convex when hot, as the base expands. A vessel designed for induction should be ground flat and should stay flat — which is why our induction kadai has a ground flat base rather than the rounded bottom a traditional kadai carries.

Test three: base diameter

An induction hob has a coil of a specific size, and the vessel base should roughly match it.

• Too small and the hob may not detect the vessel at all.
• Too large and only the central area heats, leaving the rim cold — the same problem a gas burner has with a wide pan, which is what copper bases exist to solve.

Check your hob's specified minimum and maximum base diameter and buy inside it.

What does not matter

• Whether the sides are magnetic — for function. Only the base couples.
• Mirror finish — cosmetic.
• Weight — a heavy vessel takes longer to heat but holds temperature better, exactly as on gas.

Commercial induction specifically

Commercial induction hobs are considerably more powerful than domestic ones and less forgiving of a poorly matched vessel. If you are fitting an induction kitchen, tell us the hob model and coil diameter and we will size the vessels to it. Most of our range is made to order anyway.