How can a stovetop be smooth, flat, and eternally cool?
PREMIUM They can be noisy, and they only work with certain grades of metal, but induction cooktops have come a long way. They don’t even cost much more than a gas range today. (Shutterstock)
Induction cooking feels like something out of a sci-fi movie, but the truth is, it has been around for almost a century.
The technology made its debut at the 1933 Chicago World’s Fair (themed Century of Progress). A range of demonstrations, including one by General Motors, showed crowds how a pot of water could be made to boil on a stovetop that could be touched at all times.
This works because of a magnetic field that affects the metal of the pan, causing molecules to shift rapidly, which generates heat in the pan, but nowhere else. (More on that in a bit.)
The catch was the price. Induction cooktops require powerful copper coils, high-frequency electronics and fancy cooling systems for the coils. They also only work with pans made from a certain grade of metal. In addition to which the early machines were really noisy. All this drove the price up and the appeal down. All in all, the world just wasn’t ready for it yet.
It would take half a century for the technology to quietly mature.
By the 1980s, though, cookware makers were labelling pans “induction-friendly”. The cooktops themselves were becoming smaller, quieter, more efficient and more affordable. Chefs began to notice how quickly and uniformly they heated things: a good setup can boil water almost twice as fast as a regular gas range, and keep sauces at a steady simmer.
Here’s how it works. Under the surface, a coil carries the potential for a high-frequency electric current. Flip a switch (such systems are typically powered by electricity) and it begins to generate this current, creating an oscillating magnetic field. Pop a ferromagnetic pan, made of a metal such as cast iron or certain kinds of stainless steel, on the surface and the magnetic field causes eddy currents in the metal, which leads to vibration and heat.
The cooktop itself, usually made of glass or ceramic, stays cool because it is unaffected by such magnetic fields.
Meanwhile, a lot of the initial niggles have been ironed out. High-frequency electronics kept prices relatively high for decades, but chips are now far cheaper, with the result that a good induction cooktop and a good tabletop gas range cost more or less the same. With a range of coils embedded in each high-end set-up, one can use pans of any size without trouble, and use multiple pots at the same time.
In addition, keeping these cooktops clean is a breeze. One can even place a paper towel under each dish to soak up spills, since the induction system has no effect on paper. (Avoid anything thicker, such as wood or plastic, though. These can interfere with the magnetic field and weaken it.)
My favourite thing about these systems is how safe they are for children and for seniors with unsteady hands. The risk of burns is reduced. Features such as automatic pan detection, timers, child locks and foreign-object detection help prevent accidents.
There are a few downsides. All aluminium, copper, glass, ceramic and non-magnetic stainless-steel pans are rendered useless. Kadais and woks, no matter the material, don’t fare very well either. Their curved bases leave too small a point of contact with the magnetic field. As a result, the pan cannot heat up effectively. (There are special concave induction burners that help, but that requires an added purchase.)
The sound levels can still be a surprise. As the high-frequency current causes its vibrations, the pan actually resounds. (Incidentally, heavy cast iron makes far less noise, while still heating up effectively.)
I have cooked on induction cooktops while on vacation, and found them impressive and easy to use. But I won’t be switching from my gas burner any time soon. I love how simple and effective a gas range is. I like the way the flame hugs the cookware, bending and wrapping itself around any pan. I am never stranded in a blackout.
Crucially, one cannot easily make phulkas on an induction stove. This means no roasted papads, and no baingan bharta either. I’m not quite ready for that.
(To reach Swetha Sivakumar with questions or feedback, email upgrademyfood@gmail.com. The views expressed are personal)
Dining and Cooking