There are currently two types of induction cooktops available:
Multi-element induction cooktops resemble a flat electric range and are hardwired with 220 volt electricity. They have individual burners with ratings up to 3600 watts. Typical built-in induction cooktops cost $2000-3000.
Portable induction cooktops are self-contained units with a single element and have a standard 120 volt electric cord. These units can be used on any countertop or work surface and are the type compared in this article.
Induction is unlike any other form of cooking heat, but the results of induction heating have the same affect on food. Unlike gas or electric cooktops, an induction cooktop does not generate any heat. Instead, the induction cooktop creates an electro-magnetic field that causes the metal of the pan itself to get hot. All of the energy is transfered directly to the bottom of the pan so no heat is lost in the process.
Induction is not like microwave cooking which uses a different type of cooking process. Induction creates a hot pan exactly like a gas or electric burner. If you can cook it on gas, you cook it on induction, AND achieve the identical results.
The two major benefits of induction cooking is speed and energy efficiency.
Energy efficiency is one of the main selling points of induction cooking. The US Dept of Energy says that induction cooking has an absolute efficiency of 84% while gas and electric have efficiency ratings less than 50%. But the overall benefit of induction may be even greater because often the lost ambient heat from gas and electric cooking must in turn be cooled or mechanically removed from the kitchen. There is an amazing difference in ambient heat when using induction; standing within 12 inches of pot of boiling water on a gas range, you will feel a lot of heat in the air, but with induction, you see steam rising from the pot but feel absolutely no ambient heat unless you put your hand directly over the pot.
The speed of induction cooktops depend on its wattage rating; with a higher wattage rating, more heat will be generated at the maximum power setting. The heat produced by the induction process is regulated by adjustable power levels. An increase or reduction of the power level results in more or less electro-magnetic energy, and has the same affect as turning a gas burner up or down.
Hot Water Test
I compared the time required to heat 8 cups of 61°F tap water to 200°F. All tests used the same All-Clad stainless steel pan, except the microwave test which used a pyrex bowl. Measurement of the water for all tests used the pyrex measuring bowl. Here are the results in order of speed performance. Times are in minutes and seconds.
Vollrath Mirage Induction (1800 watts) = 8:55
Gas range (2100 btu) = 10:29
Waring Pro Induction (1400 watts) = 11:27
Microwave oven (900 watts) = 17:52
Use in Cooking
You can cook literally any type of food on an induction cooktop. The only difference with induction cooking is the mechanism for making the pan hot--nothing more, nothing less. While speed and energy efficiency are often sighted as quantifiable advantages, there are other benefits which are slightly more subjective.
Once I became accustomed to induction cooking, I was pleasantly surprised by the instantaneous pinpoint control that I have over the temperature of the pan. While it is hard to imagine anything more intuitive than a gas flame, numerical power settings combined with instant response are very addictive, and I find them more accurate.
Both my wife and I agree that cookware cleanup is easier with induction, particularly cooked liquids. Food does not seem to adhere to the bottom of the pan as readily, and evaporating liquids do not create as much crust on the side of the pan at the liquid line. I can only guess that this is because all heat is generated from the bottom of the pan--there is no fire/heat enveloping the sides of the pan.
The cookware (pots and pans) used for induction cooking must be magnetic metal. If a magnet will stick to the bottom, the pan will work. Stainless steel and cast iron are good choices, but aluminum, copper, and glass will not work. Suitable cookware with non-stick coatings are also OK to use.
The two units review below represent two different price points but still fall within the midrange of currently available models. The Waring Pro is an inexpensive unit with minimal features. The Vollrath is a more powerful unit with more features, including temperature controlled cooking. The Vollrath also has a longer electrical cord and more safety features.
The Waring Pro was a gift from my wife. It served as my introduction to induction cooking and has performed flawlessly. Once I was hooked on induction, I decided to get another unit to fully convert from gas to induction. I found the Vollrath at my local restaurant supply store and was intrigued by the additional power and temperature control.
Waring Pro Induction Cooktop (ICT100), 1400 watts, 120 volts, approx. $170.00
• 11 long x 13/5 wide x 3 high (inches)
• brushed metal and plastic housing with glass cooktop
• On/Off, power level, and timer touch controls
• 7 power levels
• 99 minute timer
• ceramic cooktop
• 45 second auto-shutoff if no cookware is present
• power levels and timer controlled by touch controls
• 36 inch power cord
Vollrath Mirage Induction Cooktop (59500), 1800 watts, 120 volts, approx. $450.00
• 15 long x 14 wide x 3 high (inches)
• brushed stainless steel housing with ceramic cooktop
• On/Off and function touch controls
• rotary knob controls power levels, temperature, or time
• 100 power levels or F°/C° temperature control
• 180 minute timer
• 60 second auto-shut-off if no cookware is present
• empty pan shut-off and overheat protection
• small article detection so unit will not operate if a spoon, watch, etc. is left on the cooktop
• 72 inch power cord
The price difference of these two units is substantial--$170 vs. $450--but I feel both are a good value.
The Waring Pro is a very adequate entry level appliance that works exactly as promised. Although it may not heat any faster than your existing range, you will still benefit from significant energy efficiency.
The Vollrath Mirage offers 28% more power, temperature controlled cooking, longer timer operation, and more precise power level control via the rotary knob. It also remembers your last used power level, time, and temperature settings, even after the unit is turned off.
Both units have a very quiet internal cooling fan that will continue to run, as needed, after the unit is turned off. In addition, the Vollrath LED display will read "hot" until the cooktop cools to a safe temperature.
Price and power aside, I feel the Vollrath is a good choice for anyone who would enjoy the temperature controlled cooking feature. For a long simmer or any number of other tasks, the set it and forget it temperature accuracy is a great feature. In practical use, I have found it will maintain temperatures at ±5°F.
In addition to Waring and Vollrath, a quick web search found portable induction cooktops also available from Sunpentown, Viking, Max Burton, CookTek, and Fagor, with prices ranging from $82-1586.