“Induction cooker? That’s just a fancy name for some hotplate, right?” a friend once asked this writer, over a Lunar New Year steamboat than was frothing merrily away on one.
An induction cooker is so much more than a hotplate or gas cooker. It’s technology that moves beyond the traditional ‘heat source heats cookware to cook food’ process.
Induction cookers turn cooking vessels into heating elements in their own right.
Multitudes of ignorant people have purchased induction cookers without knowing what they entail, and end up bringing them back to retailers, demanding refunds because they “just won’t work”. Here’s what you should know before you buy an induction cooker:
Ferrous Materials Only
Induction cookers utilise magnetization to cook your food, so you’ll be needing cookware that contains substantial amounts of ferrous material (iron recommended) to get that batch of soup boiling (fans of claypots, copper cookware and the like may face disappointment here).
Cast iron is an instant win; being made from almost pure iron, cooking vessels forged from cast iron heat up the most efficiently atop your induction cooker.
Coming in a close second is steel and its variations. Steel contains various alloys and other substances apart from iron and hence does not heat up quite as effectively as its unadulterated brother. You’ll be glad to know that your entire range of stainless steel pots and pans are going to work excellently with your new induction cooker.
If the above-mentioned look like pure Greek to you, a simpler and more practical way of shopping for compatible cookware is to use a magnet.
Yes, it’s time to put that dreadful cartoon character stuck to your fridge door (which your 8-year old absolutely adores) to good use.
Bring the magnet along with you on your shopping trip and hold it within 1cm of the pot’s surface. If it sticks, you’re holding a pot that can work with the mysterious innards of your induction cooker.
So why does cookware have to be magnetic to work? What’s going on at the flick of your induction cooker’s power switch?
Well, plenty, actually.
As the cooking vessel placed on the ceramic plate is made from a ferrous material, which is very magnetic, this magnetic field then induces a circulating electrical current, or ‘eddy current‘, within the vessel. As iron is a bad conductor of electricity with a high electrical resistance, this causes heat to be generated within the vessel. A process called ‘hysteresis’, which is the resistance of the ferrous material to rapid changes in magnetization, also adds to the heat generation process.
The metal in the vessel, being an excellent conductor of heat, further accelerates the spread of heat within the vessel, causing it to heat up quickly.
It is this heat that cooks your food and adjusting the heat setting on your induction cooker simply speeds up the frequency of its magnetic field, increasing the intensity of the eddy current and hysteresis and hence the amount of heat generated within your cooking vessel.
As for the clueless friend, this writer hopes you’ve finally gotten the picture. But if, somehow, you come away with the words ‘magnetic hotplate’ in mind, I’ll just have to re-explain it to you over next year’s steamboat dinner.
*This story is the first installment in a two-part series on Induction Cookers. View Part 2 here.
**Main image courtesy of Phillips Electronics Singapore Pte Ltd, “Iron” original image courtesy of Heinrich Pniok and “Induction Cooker Parts” image courtesy of Walter Dvorak, both distributed under the Creative Commons License.