How do induction stoves actually work?
Induction stoves are climate-change-fighting machines, kicking fossil fuels out of the kitchen.
They’re healthier to use than gas stoves and up to three times more efficient (as well as up to 10 percent more efficient than traditional electric resistance stoves), according to the U.S. Department of Energy. And in displacing gas stoves, they could also be key to helping cut the carbon emissions of buildings, which account for about 35 percent of energy-related emissions in the U.S.
Induction stoves are in only a sliver of American homes, but that doesn't mean people aren’t justifiably curious about them: 69 percent of U.S. adults surveyed said they might go with induction for their next stove, according to Consumer Reports. (Lucky them! The Inflation Reduction Act contains incentives to do exactly that.)
So, how exactly does the stove of the future work? Let’s break it down.
Induction 101
Imagine yourself in front of an induction cooktop. You put an induction-compatible pan down on its scratch-resistant ceramic-glass surface and turn it on. What happens next?
Well, first we have to understand what's under the "burner."
When powered on, an alternating electric current begins to course through this electric coil. In the U.S., alternating current reverses its direction 60 times per second. But in the induction stove, power electronics make the current cycle much faster: 20,000 times or more per second. That process requires a huge amount of power, which could come from an upgraded 240-volt outlet or an added battery.
As the coil’s current ping-pongs at superfast speed, it induces a fast-changing magnetic field. And that changing magnetic field has a superpower: It can induce electric current to flow in a metal pan.
These currents flow in a way that counteracts the magnetic field, generating their own magnetic field to oppose the original one.
As these “eddy currents” swirl like eddies in a river, they run into resistance and generate heat. While certain pans don’t work with induction cooktops, pans made of ferromagnetic materials, such as cast iron and some stainless steels, are really good at heating up in this way.
And voilà! Induction makes your pan hot so you can cook whatever you want, like pancakes, polenta or water for pasta. (The same induction physics also pop up in other futuristic applications, from eddy-current brakes to wireless charging.)
Other forms of cooking aren’t as elegant as induction, according to Sam Calisch, co-founder and chief scientist at Channing Street Copper Company, an induction-stove startup, who explained induction to me one sunny afternoon. With a gas stove, a flame must heat up ambient air to warm a pan. But induction cuts out the middleman; with its invisible electromagnetic tendrils, the technology can heat a pan directly. And that makes for a better cooking experience, he contends.
“As soon as you turn the knob, a different amount of heat is flowing into the pan, and therefore the temperature changes much more rapidly and much more precisely,” Calisch said.
Now that’s cooking with electromagnetism.
Want to see induction cooking up close? Check out Canary Media’s Julian Spector trying it out.
