Induction is a method, completely different from all other cooking technologies– it does not involve generating heat which is then transferred to the cooking vessel, it makes the cooking vessel itself the original generator of the cooking heat.
1. The element’s electronics power a coil (the red lines) that produces a high-frequency electromagnetic field.
2. That field penetrates the metal of the ferrous (magnetic-material) cooking vessel and sets up a circulating electric current, which generates heat.
3. The heat generated in the cooking vessel is transferred to the vessel’s contents.
4. Nothing outside the vessel is affected by the field–as soon as the vessel is removed from the element, or the element turned off, heat generation stops.
An induction cooker uses a type of induction heating for cooking. It is chiefly distinguished from other common forms of cooking by the fact that the heat is generated directly in the cooking vessel.
A coil of copper wire is placed underneath the cooking pot. An alternating electric current is made to flow through the coil, which produces an oscillating magnetic field which creates heat in the cooking vessel over it, which must be made of a magnetic material (ferromagnetic) and electrically conductive, in two different ways.
Principally, it induces an electric current in the pot, which produces resistive heating proportional to the square of the current and to the electrical resistance of the vessel. Secondly, it also creates magnetic hysteresis losses in the pot due to its ferromagnetic nature.
Induction cookers are faster and more energy-efficient than traditional electric cooktops; moreover, they allow instant control of cooking energy, which no energy source other than gas offers. Because induction heats the cooking vessel itself, the possibility of burn injury is significantly less than with other methods: only skin contact with the cooking vessel itself (or, when high heat has been used, the stovetop for a while after the vessel has been removed) can cause harm. There are not the high temperatures of flames or red-hot electric heating elements found in traditional cooking equipment, which generates heat independent of the cooking vessel. Further, induction cookers do not themselves warm the surrounding air, resulting in further energy efficiencies.
Since heat is being generated by an induced electric current, the unit can detect whether cookware is present (or whether its contents have boiled dry) by monitoring the voltage drop caused by resistance in the circuit (which reflects how much energy is being absorbed). That allows such functions as keeping a pot at minimal boil or automatically turning an element off when cookware is removed from it.
- Less electricity is wasted compared with a conventional hot plate.
- The kitchen is heated up less by waste heat.
- The bottom of the pan is not burned by the stove and stays clean.
- Food spills and boil-overs aren’t burned on to the stove and are easily wiped off. Most stove-tops are easy-to-clean glass or ceramic.
- The pot can be conveniently left on the stove after cooking, without residual heat from the stove burning the food.
- The pot reacts instantly to changes in power, like a gas stove, because the stove itself doesn’t need to heat up or cool down first.
- A fan is used to cool the electronics. This can be noisy. The electronics or the magnetic field might also create a buzzing or humming noise.
- For safety, the stove will switch off if the pan is removed. This will interfere with cooking techniques that involve tilting or lifting the pan.
- Induction stoves need a minimum pan diameter to work. Pans that are too small will not be recognized and the stove will not switch on.
- The heated area might not cover the entire stove top. This is not an issue for boiling but can cause problems when frying. To check the heated area (typically a 5 inch diameter circle) a pan of water is heated on the stove. The pattern of the bubbles at the bottom of the pan will show the heated area.