Speaker 1: Welcome to brain Stuff, a production of iHeartRadio, Hey brain
Speaker 1: Stuff Lauren Bobobomb. Here the principle of cooking food in
Speaker 1: a pot or pan atop a heat source that hasn't
Speaker 1: changed much since the dawn of cookware. The cookware acts
Speaker 1: as the intermediary between the heat source and the food.
Speaker 1: The main weakness here is that the heat source, be
Speaker 1: it an open fire or a tiny gas flame or
Speaker 1: an electric element, only directly heats the part of the
Speaker 1: cookware that touches it. The rest of the cookware is
Speaker 1: warmed by heat conduction, and as a result, the food
Speaker 1: receives different amounts of heat from different parts of the
Speaker 1: pot or pan. This is why with conventional heating elements
Speaker 1: like an electric or gas stovetop, we have to rely
Speaker 1: on the slow process of convection to heat a stew
Speaker 1: all the way through, and have to stir some foods
Speaker 1: constantly to prevent them from from burning in the pan.
Speaker 1: Electric elements, in particular, tend to toggle on and off
Speaker 1: to keep an overall steady temperature, which can lead to hotspots.
Speaker 1: This is why recipes for delicate sauces like chocolate ganache
Speaker 1: or a hollandaise traditionally want you to heat your ingredients
Speaker 1: in a vessel over steaming water instead of directly on
Speaker 1: a cook top. This conducts heat to the floor of
Speaker 1: the pan more evenly, helping you reduce the risk of scorching, boiling, separation,
Speaker 1: and other heartaches. And this has been what's up for millennia.
Speaker 1: But within the past fifty years or so, a new
Speaker 1: use of technology has provided a different option. Induction cook
Speaker 1: tops help you heat food more evenly by cutting out
Speaker 1: the middleman and turning the cookware itself into the source
Speaker 1: of heat as long as that cookware is made of
Speaker 1: the right stuff. Iron or steel pans work well, but
Speaker 1: pretty much any other material that you put on the
Speaker 1: cook top, like aluminum or pyrex or your hand won't
Speaker 1: get hot. Induction cooktops also feature precise temperature control and
Speaker 1: the capacity for very low temperature settings, all while working
Speaker 1: more efficiently and producing less waste heat in your kitchen.
Speaker 1: An induction cooktop can do all of this because of
Speaker 1: the properties of electricity and magnetism. Magnets are not magical.
Speaker 1: We know how they work, though it is true that
Speaker 1: the force that governs them electromagnetism, is many times stronger
Speaker 1: than gravity. The suspension of a maglev train above its
Speaker 1: track is a striking example of this point. Electricity and
Speaker 1: magnetism can affect each other without physical contact through electromagnetic fields.
Speaker 1: This is what's happening in induction. Cooking a circuit with
Speaker 1: an alternating current flowing through it inside the stovetop generates
Speaker 1: current in another circuit in the pan simply by placing
Speaker 1: the pan nearby. The pan converts that current into heat.
Speaker 1: But okay, that's a lot. Let's unpack it. There are
Speaker 1: some basic principles of electromagnetism at work here. Every electric
Speaker 1: current has a magnetic field surrounding it. An alternating current
Speaker 1: is an electric current that periodically reverses direction, which is
Speaker 1: useful because that means that its magnetic field also fluctuates.
Speaker 1: This is useful because fluctuating magnetic fields induce currents to
Speaker 1: start flowing and electrically conducive materials placed within those fields.
Speaker 1: Alternating current is the type of current used to send
Speaker 1: power through lines to homes and businesses and libraries and
Speaker 1: everything else on the grid. Because of these properties, induction
Speaker 1: allows high voltage current from power lines to be stepped
Speaker 1: down through passive conductive devices called transformers that make the
Speaker 1: current low voltage and safe enough for actual use by
Speaker 1: you and all of your appliances. Induction is also the
Speaker 1: principle that makes everything from electric generators to electric toothbrushes possible.
Speaker 1: For induction cooking, it's important to remember one more principle,
Speaker 1: electrical resistance. You know, some materials are good at conducting electricity,
Speaker 1: and some materials conducted poorly or resist it. Induction cooking
Speaker 1: works because iron and steel are magnetic, so you can
Speaker 1: induce current in them, but they are also just complete
Speaker 1: crud at conducting electricity, so they convert that current to
Speaker 1: heat and heat up like almost instantly. A lower current
Speaker 1: will create less heat, a higher current will create more,
Speaker 1: and you can use the controls on the induction element
Speaker 1: to turn it up or down. I find it useful
Speaker 1: to think about light bulbs when considering electric current flow
Speaker 1: and resistance. An incandescent light bulb on a cord is
Speaker 1: a great example of both. You've got current flowing to
Speaker 1: it nice through the conductive wire in that cord, but
Speaker 1: inside the bulb the current encounters a different kind of wire,
Speaker 1: a filament that resists flow like all heck, and as
Speaker 1: a result, it gives off visible light and heat. So
Speaker 1: that's a simple example of how you can harness the
Speaker 1: flow and resistance of a current in different materials. An
Speaker 1: induction cooktop is a little more complicated. It contains an electromagnet,
Speaker 1: a type of magnet in which you create the magnetic
Speaker 1: field by introducing electric current to the device, So you
Speaker 1: can turn the magnet on and off, and you can
Speaker 1: make the magnetic field weaker or stronger with the amount
Speaker 1: of current you apply. In the case of an induction
Speaker 1: cooktop element, your electromagnet is probably a spiral of tightly
Speaker 1: coiled copper cable. So you turn the element on and
Speaker 1: it sends an alternating current through the cable, which creates
Speaker 1: an alternating magnetic field above the cable, which is near
Speaker 1: the surface of the cook top, just below a protective
Speaker 1: finish made of glass and ceramic, you know, the same
Speaker 1: as what you'd have on some conventional electric cooktops. Well,
Speaker 1: when you put something that is not magnetic in that
Speaker 1: alternating magnetic field on that cook top, nothing happens. You
Speaker 1: can toss a stack of paper on there, or put
Speaker 1: your big silly hand right on it, and you won't
Speaker 1: feel any heat because there isn't any unless you happen
Speaker 1: to be wolverine, and we've decided that adamantium is ferromagnetic. Anyway,
Speaker 1: when you put something that is magnetic in that field,
Speaker 1: like a ferromagnetic cast iron, stainless steel, or carbon steel pan,
Speaker 1: the field will induce an electrical current in the material
Speaker 1: of the pan. Because the field is alternating, the current
Speaker 1: in the pan flows or kind of swirls like an
Speaker 1: eddy or it tries to, but the metal resists it,
Speaker 1: and thus it creates heat. In order to create enough
Speaker 1: heat to be useful for cooking, you need a very
Speaker 1: high rate of change in the magnetic field, and this
Speaker 1: a high frequency of alternating current flowing through the electromagnet.
Speaker 1: Induction cooktops accomplish this via a series of electronic devices
Speaker 1: that increase the current and frequency while also protecting your
Speaker 1: home and appliance wiring, including a transformer, rectifier, and inverter.
Speaker 1: When the current finally reaches the induction coil, it's been
Speaker 1: increased to a frequency roughly a thousand times higher than
Speaker 1: that of a wall socket. But practically all of this
Speaker 1: means that not all cookwar will work with induction devices.
Speaker 1: A ferromagnetic materials work because they are susceptible to magnetic fields. Basically,
Speaker 1: because their electrons are unbalanced. Any given atom in them
Speaker 1: will have an upspin or a down spin, and thus,
Speaker 1: in certain circumstances can behave like a magnet. Some stainless
Speaker 1: steel even will contain too much nickel for this to work.
Speaker 1: If you've got a favorite pan and you're not sure
Speaker 1: what it's made of, you can check whether it'll work
Speaker 1: on an induction cooktop by taking a normal old fridge
Speaker 1: magnet and trying to stick it to the bottom of
Speaker 1: the pan. If you've got a newer pot made of
Speaker 1: a copper or whatever, you might want to check. Some
Speaker 1: manufacturers have started adding an iron plate to the bottom
Speaker 1: of their non ferrost cookware to allow them to work
Speaker 1: with induction. If the magnet sticks, you're good to go.
Speaker 1: If it falls off, you're out of luck. Also, some
Speaker 1: induction cooktops have built in detectors that will tell you
Speaker 1: if a potter pan is appropriate. Oh, and they usually
Speaker 1: include an indicator light to tell you when the unit
Speaker 1: is on. Since you won't feel any heat, so this
Speaker 1: is certainly a clever way of producing heat for cooking,
Speaker 1: but like all technologies, it does have its pros and cons.
Speaker 1: Induction cooktops are more energy efficient. It's estimated that gas
Speaker 1: cooktops are able to convert about thirty eight percent of
Speaker 1: their energy in to the food in the pan. Electric
Speaker 1: can convert about seventy percent, Induction can convert over eighty percent.
Speaker 1: Induction cooktops also heat faster than gas or electric, and
Speaker 1: as precisely or more so than gas. Induction is also
Speaker 1: safer because these ceramic glass cook top doesn't get hot,
Speaker 1: you reduce the risk of burns or fires, though note
Speaker 1: that the surface can get warm due to heat transfer
Speaker 1: from the pan. Gas in particular causes indoor air pollution
Speaker 1: and is volatile. Misalignments and other issues can cause gas
Speaker 1: to leak into a home, creating serious hazards. Induction surfaces
Speaker 1: are also easier to clean than exposed electric coils or
Speaker 1: gas grates. Downsides include that it's just a different technology
Speaker 1: that you have to get used to using. It can
Speaker 1: heat things some fifty percent faster, so you've got to
Speaker 1: watch stuff at first and adjust your expectations. Induction units
Speaker 1: are still more expensive than conventional units as well, enough
Speaker 1: so that as of now you're unlikely to make up
Speaker 1: the cost difference in energy savings. Induction does tend to
Speaker 1: operate with a bit of noise, a buzz or vibration,
Speaker 1: and or some fan noise. Some are designed with fans
Speaker 1: in the base, so you might not be able to
Speaker 1: install them over an existing oven and would have to
Speaker 1: replace the whole range. If you are replacing an existing
Speaker 1: cooktop or range with induction, check with an electrician to
Speaker 1: be sure that your wiring, voltage and ambriage can handle
Speaker 1: the load. Improper installation can also interfere with radio or
Speaker 1: television reception, and experienced electrician can help you avoid that
Speaker 1: or constantly tripping your breakers or worse. There are some
Speaker 1: other rare safety issues because this is an electromagnetic device.
Speaker 1: If you have a pacemaker or something similar, you might
Speaker 1: want to check with your doctor first. You certainly don't
Speaker 1: want to create any interference with that. In a similar
Speaker 1: but less serious vein, you probably won't be able to
Speaker 1: use a digital thermometer to read the contents of a
Speaker 1: pan while the induction unit is on. Cooktops using induction
Speaker 1: technology were experimented with as early as the nineteen thirties,
Speaker 1: but didn't hit the consumer market until the nineteen seventies.
Speaker 1: It's caught on faster in Europe and Asia, but the
Speaker 1: market is becoming more competitive in the US too, especially
Speaker 1: as fuel expenses rise and with legislation in places like
Speaker 1: California moving away from new gas installations, it's expected that
Speaker 1: more people and businesses will be induced to adopt induction.
Speaker 1: Today's episode is based on the article how induction cooktops
Speaker 1: work on how stuffworks dot Com, written by Nicholas Jervis.
Speaker 1: Brain Stuff is production of iHeartRadio in partnership with how Stuffworks.
Speaker 1: Dot Com is produced by Tyler Klain. For more podcasts
Speaker 1: from my heart Radio, visit the iHeartRadio app, Apple Podcasts,
Speaker 1: or wherever you listen to your favorite shows. Hmm