On Food and Cooking

and 40,000 cycles per second). The current
causes the coil to generate a magnetic field
that extends some distance from the coil,
and that alternates at the same rate. If a pot
made from a magnetic material — cast
iron, steel, stainless steel of the proper
crystal structure (ferritic) — is placed near
the coil, then the alternating magnetic field
induces an alternating electrical current in
the pot. That is, it causes electrons to move
in the pot, and that movement rapidly
generates heat.
Induction heating has two notable
advantages over burners and radiant
elements. Like microwave heating, it’s
more efficient, because all the energy goes
into the object to be heated, not into the
surrounding air. And only the pot and its
contents get very hot. The ceramic surface
above the induction coil is heated only
indirectly by the pot, because its electrons
aren’t free to be moved by the magnetic