Induction cooker

Encyclopedia : I : IN : IND : Induction cooker

An induction cooker uses induction heating for cooking. Usually a ferromagnetic or ferromagnetic coated pot is placed above an induction coil for the heating process to take place.

Contents

0.1 Benefits
0.2 Economic considerations
0.3 Common usage
0.4 Technical aspects

1 Vendors
2 See also
3 External links

Benefits

This form of flameless cooking has an edge over conventional gas flame and electric cookers as it provides rapid heating, vastly improved thermal efficiency, plus the same or greater degree of controllability as gas. A pot of water comes to the boil in as few as 5 seconds, and then upon turning down immediately (in a second) transitions to simmering.^{[[Citing sources citation needed]]}

It is considered safer because there are no open flames and the heater itself is not hot to the human touch; only the pan becomes hot. Bosch brochures, for example, show a person touching the ceramic cover to the inductor while along side is a pan of boiling water heated by the same induction source.

It is also easier to clean because it is one large flat, smooth surface, even though it may have 2,3, 4 or even up to 8 zones of heating induction. In addition, it doesn't suffer from the problem ceramic hobs have when pans boil over - as the surface of the hob itself doesn't get hot the food cannot get "burnt on".

Economic considerations

Induction cookers are considerably more expensive than traditional cookers, but consume half as much electricity as electric cookers and are more efficient in heat transfer.

Common usage

Most induction cooking is done on stovetop units, which may be built into a countertop or may be a portable unit. In this style of cooking, the electromagnet is usually sealed beneath a heat-resisting glass-ceramic sheet which is easily cleaned. The pot is placed on the glass coating, and begins to heat up along with its contents.

Technical aspects

In induction cooking, Heat is generated in two ways:

Magnetic hysteresis. The rapidly oscillating magnetic field causes power in the magnetic field to be converted to heat in the ferromagnetic base of the pot due to hysteresis. The amount of heat produced is proportional to the area of the hysteresis loop. This is the primary source of heat.
Eddy currents. The magnetic field also produces electric currents (known as eddy currents) in the metal base of the pot, and these cause resistive heating of the metal.

The heat from the pot is then transferred to the food by conduction, but very little heat is transferred to the actual stovetop. After boiling a pot of water, the surface of an induction stove is slightly warm to touch but not so warm as to burn or even hurt human flesh. Furthermore, within 1 to 5 seconds it cools to room temperature.

However, a pot or saucepan with a copper base or made of aluminium will not work on an induction cooktop. As an induction cooktop relies on the two methods itemised above to generate heat, copper and aluminium, which are not ferromagnetic materials, will perform poorly. Note that eddy currents will be generated in the copper and aluminium, but commercially available induction cooking cannot generate sufficient heat via eddy currents alone in copper and aluminium saucepans for effective heating. Pyrex glass and ceramic containers will not be heated by either method, as such containers are neither ferromagnetic, nor capable of carrying eddy currents.

Vendors

The set of Vendors of induction hobs is dominated by German players, such as AEG, Bosch and Siemens. The Italian firm Smeg is also a key player in this market. Prices range from about £400 to £1000. Units may have two, three, four or five induction zones, but four is the most common. Some have touch sensitive controls. Some Bosch induction stoves have a memory setting, one per hob, that is able to time the amount of heat required. For example, given an exact measurement of water and food, the memory setting can deliver just the right burst of power to bring the saucepan to the boil and then automatically turn it down to simmer for the prescribed number of minutes. Potatoes, for example, take 12 minutes to cook, whereas sweetcorn is best after just 3 minutes in boiling water. The Bosch memory can include five settings per hob - so for example the corn is automatically brought to the boil, simmered, and then turned off.

External links

[The Induction Site] - Induction-cooking principles and complete equipment database

From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.