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The Induction Cooktop

One
of the many applications of induction heating is cooking. The induction
cooktop, while not yet a part of most households, is becoming increasingly
accepted as a useful, energy efficient method of preparing food. They
come in a variety of forms, from full-sized four-hob ranges (Figure
1) to portable one-hob hot plates (Figure 2). The portable cooktops
are very popular with catering businesses, as they are much cheaper
and safer to operate than comparable butane units. They cook food quickly,
are easy to use, and are easy to clean. Induction cooktops can be used
with any type of food, and will cook as throughly and evenly as any
electric or gas range.

 
 

Figure 1: Atag H5311M Induction Range (Image from
the Bradshaw Group)

 





 
 

Figure 2: CookTek Portable Cooktop (Image from Cooktek
Online)

 

 

 

 

 

 

 

 

 

 

 

 

 

This page contains the following topics:

  How does an induction cooktop work?

  How does an induction cooktop compare to other
cooktops?

  Will I have to buy special cookware?

  Summary

How Does an Induction Cooktop Work?

 
 

Figure 3: Diagram of an Induction Cooktop (Image from
Cooktek Online)

 

Induction cooktops have many advantages over other
cooking methods, including efficiency, controllability, and safety.
These advantages are easily explained by discussing how they work. Each
hob contains one or more coils made of ferromagnetic material. When
an alternating current is passed through these coils, a magnetic field
of the same frequency is produced. If a magnetic-based pan is placed
on the hob, the magnetic field induces a current in the pan. The internal
resistance of the pan causes heat to be dissipated, following the Joule
effect. Thus it is the pan itself, and not the cooktop, that heats up
and cooks the food. Once the pan is removed from the cooktop, the energy
transfer stops. The result is a flame-less method of cooking in which
it is nearly impossible to start a fire by forgetting to turn off the
stove. Parents won't have to worry about their child touching a hot
burner because the cooktop surface remains cool. Changing cooking temperatures
is achieved quickly because there is no wait for the hob to heat up,
only the pan. Since there is no transfer of heat energy between the
hob and the pan, less heat is lost into the air, resulting in a more
efficient means of cooking, not to mention a more agreeable cooking
environment.  

How Does an Induction Cooktop Compare
to Other Cooktops?

According
to CEG Electric Glass Company, a producer of induction cooktops, "power
savings of 40-70% are realistically achievable in comparison to conventional
cooktops." The following statistics are taken from CookTek Online.
For the reasons discussed above, it is not surprising that induction
heating results in the highest efficiency.

Table 1: Efficiency of Cooking Methods

Cooking Method

Efficiency

Induction

90%

Halogen

58%

Electric

47%

Gas

40%

 
 

 

This shows that using an induction cooktop can result in greatly reduced
power bills. Other tests show that induction cooking is faster than
using gas, halogen, or a microwave. As mentioned above, the induction
cooktop is extremely safe. There is no risk of fire if food or grease
overflows from the pan, no risk of burns from touching the cooktop surface,
and no worry about dangerous fumes from gas or other cooking fuels.
The ceramic glass surface can be cleaned by simply wiping off the surface
with a damp towel. Although induction ranges are currently more expensive
than their electric or gas counterparts, when all of these advantages
are taken into account, the induction cooktop will definitely pay for
itself.

Will I Have to Buy Special Cookware?

 

Induction cooking can be used with any type of cookware from frying
pans to woks. However, the induction cooktop only works when used with
magnetic-based materials, such as iron and steel, that will allow an
induced current to flow within them. A simple way to find out if a pan
is induction compatible is to use the "magnet test;" if a
magnet will stick to the surface of the pan, it will work. Many companies
produce special cookware specifically for induction cooking. These pans
are designed to absorb magnetic energy and spread the heat quickly and
evenly, resulting in higher efficiency and reduction of "hot spots,"
which can cause food to be burned in some areas while still uncooked
in others. Figure 4 below contains a detailed drawing of a CookTek Induction-Efficient
Pan.

 
 

Figure 4: CookTek Induction-Efficient Cookware (Image
from Cooktek Online)

 

 

Components of a CookTek Induction-Efficient Pan  

Courtesy of CookTek Online  

1) 18/10 stainless steel is non-reactive to
food and easy to clean. 

2,3,4) 1145 aluminum with a layer of 3004 aluminum
between for even heat distribution.  

5) 18/10 stainless steel for superior bond.  

6) Magnetic stainless steel for efficient induction.  

7) 18/10 stainless steel resists pitting and
rusting.  

 

 

 

 

Summary

 

The induction cooktop is a very practical device and can be used for
any cooking application. It cooks food just as well as any comparable
system but in a safer, more energy efficient ma