Induction cooking represents a fundamentally different method for preparing food than traditional electric resistance coils or open gas flames. This technology uses electromagnetic energy to heat the cooking vessel directly, bypassing the need for heat to travel from a hot surface or burner to the pot. The food is heated from the bottom of the pan itself, which remains the sole source of thermal energy. This establishes a highly responsive and localized heating effect.
Creating the Alternating Magnetic Field
The process begins with an internal component located beneath the smooth ceramic-glass surface of the cooktop: a coiled length of copper wire, referred to as the induction coil. When the unit is activated, an electronic oscillator passes a high-frequency alternating electric current through this coil. The flow of alternating current, which rapidly changes direction, generates an invisible, oscillating magnetic field.
This rapidly changing magnetic field extends vertically from the coil, penetrating the cooktop surface toward where the cookware is placed. The cooktop itself acts only as the generator for this magnetic energy, remaining relatively cool throughout the operation. The energy is contained within this field, waiting for the proper metallic object to complete the energy transfer cycle.
Generating Heat Through Eddy Currents
When compatible cookware is placed within this oscillating magnetic field, the field induces an electrical voltage within the metal base of the pot. This voltage drives circulating electrical currents, known as Eddy Currents, to flow within the material. The key to heat generation lies in the natural electrical resistance of the metal in the pot’s base. As these rapidly flowing Eddy Currents encounter resistance, a physical effect called Joule heating occurs.
Joule heating is the same principle that causes a traditional toaster element to glow red, but here, the heating occurs directly within the pan’s base. The energy from the induced currents is lost as heat, causing the bottom of the pot to warm up instantly. For materials with magnetic properties, an additional heat component, magnetic hysteresis loss, also contributes to the overall temperature increase. The heat is entirely generated inside the cookware, making the pot an active part of the heating system.
Cookware Requirements and System Efficiency
Induction technology necessitates the use of cookware constructed from ferromagnetic materials, which are strongly attracted to a magnet. Materials like cast iron and certain stainless steel grades contain the necessary iron content to interact effectively with the magnetic field. This magnetic interaction is required for the generation of the heat-producing Eddy Currents. Cookware made from non-ferromagnetic materials, such as pure aluminum, copper, or glass, will not heat up because they cannot efficiently absorb the magnetic energy.
The direct generation of heat within the pot is why induction cooking is a highly energy-efficient method. Unlike gas or electric resistance cooktops, very little heat is lost to the surrounding air or the cooktop surface. The cooktop surface only gets moderately warm from residual heat transferred back from the hot pan, allowing for a safer environment and quicker response times. This localized, contained heat generation results in energy transfer efficiencies that often exceed 84 percent.