This may be the sound of our culinary future.
[buzzing sound]
Technically that's not a sound. Or, at least, it wasn't a sound until your speakers or your
headphones converted it into a sound. It was not in the air in the room when I shot that
footage. It is, instead, electromagnetic interference messing with my camera — interference coming
from this induction burner, which cooks with magnetism.
These are still pretty rare here in the United States, but they're getting more popular,
most notably in China, which accounts for about 60 percent of the global induction market
share, according to this Industry Research report.
We're gonna learn the science of how induction works, why it only works with certain pots
and pans, and why you might prefer it to gas or electric. Or not. I dunno. You do you.
Let's start with a little experiment.
Here's two cups of cold tap water in a saucepan on my electric stovetop. Brits would call
it hob — any stovetop, not just an electric one, they call it a hob. Anyway, the burner
has an inner ring and an outer ring. I'm turning them both on, so this is the maximum BTUs
I can get out of this thing. My thermometer is on Celsius, and as you can see, this took
about 4-and-a-half minutes to reach a full boil. 100 degrees.
Now, same experiment on this little induction hot plate that I've got. On full power, it
takes about 3-and-a-half minutes to reach a full boil. It got there a minute faster,
despite the fact that this is an underpowered little mobile "hob" that I've got here, compared
to my state-of-the-art electric stove, which is an absolute beast, and will instantaneously
burn a steak if I've heated my pan on high for more than a couple minutes.
How is it possible that the puny induction burner heats faster than the beefy electric
burner?
Let's go ask Dr. Shannon Yee, an expert on energy and heat transfer at Georgia Tech.
"When you add more interfaces, or more material in-between, you still have to push that heat
through, and so you're getting different temperature drops along the way. With induction heating,
you're heating the pan directly."
Now what are the "thermal interfaces" on the electric stove? Well, there's the resistance
coil — that's the metal coil under the glass. Electricity heats that up. Then the heat passes
through the ceramic top (that's another interface), and only then does it reach the pan.
"You're passing electrons around and that's creating inelastic scattering, generating
heat. In the case of an induction heater, you're using a magnetic field, causing electrons
to move around and create eddy currents. Those eddy currents are causing scattering and heating
up that way. And so you're directly heating the pan, rather than heating a coil and then
relying on heat transfer to the pan."
Here's a way to see that difference in action. If I take the boiling pot off my electric
burner and then touch my thermometer to the glass, it really quickly reaches 200 degrees
Celsius, almost 400 Fahrenheit before my hand gets so hot I can't hold it there anymore.
"Ow."
I do the exact same thing on the induction burner, and the thermometer reads just 40
degrees Celsius. There was just a boiling pan of water on here, and and even though
this thing says "CAUTION, do not touch," and that's good advice, I can nonetheless gingerly
touch this glass surface. That's because the burner wasn't heating the glass. It was emitting
an alternating magnetic current that heated the pan, and then the pan conducted some of
that heat back down to the glass.
And that's good?
"Yep, you won't heat the other things around it. It minimizes burns or other injuries.
I worry about getting burned in the kitchen."
I'm sure that my lawyer and the manufacturer of this induction burner would like me to
emphasize once again that you really shouldn't just slap your hand right down onto the thing
after it's just been heating a screaming-hot pan. However, if you were to do such a thing,
the burn would probably be way less severe than if you put your hand onto a screaming-hot
electric burner, and for me, a guy who has little kids running around the house, reaching
up on things, that's a big bonus for induction.
There's also less heat going out into the air around the pot. Here, I'm holding the
tip of the thermometer in thin air, right in the crook between the pan and the burner,
and it's reading like 95 Celsius. Compare that to 40 degrees Celsius over on the induction
burner. Induction heats up your kitchen way less than electric, and WAY less than gas.
Look, I went over to my friend Seth's house. He's got a beautiful old gas stove. I tried
to do the same water boiling experiment there, and when it got it around 50 degrees Celsius,
the thermometer just stopped working.
"Hey, wake up. &$^%. Whoa, oh my god."
"Did you melt it?"
"I melted it."
"Nice!"
Yeah, that's how much heat escapes out the side of a gas burner. It's a lot of heat,
which I think probably has particular significance in the professional kitchen.
One of my favorite celebrity chefs is a big fan of induction, despite being an adorably
analog man in a digital world. That's my man Michel Roux Jr., right there. He cooked with
induction at home for a long time, and then in 2014, he brought into his kitchen at Le
Gavroche in London.
"All the sauces getting ready for lunch. And what's great about the induction is there's
no heat. It's lovely. It's a great environment to be working in."
For most of the history of professional cookery, kitchens have been miserably hot places to
work, hence the expression, "If you can't stand the heat, GTFO the kitchen." It's kinda
profound to think that now, all of a sudden, it doesn't have to be that way.
But one reason why professional chefs have traditionally liked gas is that it is "responsive."
When you fiddle with the knob, there's less of a lag time between changes that you make
here, and food actually getting cooler or hotter.
To a great extent, I think the responsiveness of gas stoves is really overstated when compared
to modern, high-quality electric ranges. This Consumer Reports article that I'm showing
you about that is linked in the description.
But regardless, induction is more way more responsive than electric. We already established
that it heats up the food faster. Now watch what happens when we turn the heat off. It
takes the boiling water over the electric burner nearly four minutes to cool down by
just 10 degrees C. On the induction burner, the same trip takes less than a minute.
That's really important when you're trying to keep something from burning. Likewise,
induction burners are probably better than electric at maintaining low constant heat,
like the bare simmer needed for making stock.
Electric burners have to constantly cycle on and off to maintain a temperature, and
at the hottest point of that cycle, they might burn your sauce. A heavy pan helps to mitigate
that, but it's still a risk. Induction burners generally only have to cycle when you get
them on full blast — they'll cycle on and off to avoid meltdown.
I should say that induction cooktops are generally more expensive, though the price is coming
down. They also only work with certain kinds of pans. The pan has to be made of a magnetic
metal — a ferrous metal, i.e. cast iron, or enameled cast iron, or steel, which of
course is mostly iron. If you're not sure what you've got, put a magnet on it — extra
points if it's shaped like a horsey. If the magnet sticks, it's gonna work. If it doesn't,
it's not gonna work. I mean, it's not gonna hurt anything. The pan just isn't gonna get
hot. I can't, for example, use my aluminum stock pot on induction. Big stock pots like
this are often made out of aluminum because aluminum is light, it's cheap. Copper pans
won't work. Pans that are clad, where you've got some copper or some aluminum sandwiched
between some steel, those will generally work. The magnet trick will tell.
Another drawback is that induction burners aren't very good for cooking with woks — forgive
me, this is the closest thing that I have to a wok. The heat doesn't really kinda wrap
up around these sloping edges the way it does with a gas flame, for sure.
With induction, the burner has to be actually touching the bottom of the pan, or at least
be very, very close to it.
That's the same reason, by the way, why it's probably perfectly safe to cook with induction
while wearing a ring. People asked me about this when I did my video about cooking in
rings. I couldn't really test this directly because my wedding ring is made out of gold,
which is not particularly magnetic. But I suppose if you had a steel ring, or maybe
a nickel ring, yeah, there's sort of a risk that the induction burner could heat up the
ring around your finger and burn you. But I just don't think that's very realistic.
Here's how we can test that. Here's my pairing knife. It's made of steel. It's ferrous. I'll
grip it tightly and then hold it right next to the induction burner on full blast, and
... I feel absolutely nothing heating up.
So yeah, the sloped sides of the wok are not gonna get very much heat on an induction burner,
nor will any of the wok if you are pulling it up off the burner to toss the food, as
traditional stir-fry technique demands, which leads us back to the interesting case of China.
They love their woks in China, and yet, oddly, they also love their induction cooktops. One
study by the research firm iResearch found that 82 percent of Chinese survey respondents
say they own one of these — a standalone, dedicated induction burner, which is great
at many things, but not at working a wok.
This report by Allied Market Research links the popularity of induction with increased
health awareness. People want to cook with less oil, which might mean less stir-frying
in woks.
A Chinese viewer of mine told me via Twitter that one of these is very handy in cramped
Chinese apartments. I imagine it's also safer there — a lot less likely to start a fire.
Then there's the issue of energy efficiency. Induction probably is a little more efficient
than electric, though the true degree of that difference is a matter of some debate. There's
some links about that in the description.
Induction certainly is more energy efficient than gas if you look within the closed system
that is your kitchen. But you gotta think about where the energy comes from. How close
do you live to your power plant? What kind of power plant is it? What kind of transmission
lines connect you to your power plant? Do you live in a hot climate or a cold climate?
All of these things can affect energy efficiency in the broader sense. And the energy cost?
Man, I couldn't tell you anything about that. The price of electricity and gas depends so
much on where you live. I have no idea what is the better buy for you in the long term.
I can tell you which burner is the noisiest though, which is where I will leave you — right
back where we started.
[buzzing sound]
No, you're not actually going to hear this sound while you're cooking with induction.
That is the electromagnetic interference acting upon the incredibly cheap audio circuitry
that is inside my camera. If I switch over to some high-quality audio gear — gear that's
actually designed to be shielded from interference, you can hear what this thing actually sounds
like in the room.
[whirring and lesser buzzing]
Yep, that's kinda noisy. There's a fan that cools it down, there's all these weird clicking
and creaking sounds, especially at maximum power. It's kinda noisy. And that is why induction
may be a great option for you, but for me, a guy who makes cooking videos with sound?
Nah, not yet.