Rice Cookers: They Do it with a Magnet!

Back in May, 2018, we had a post here about rice cookers.  That was about a very high-end unit, but the bottom of the line products often used a remarkably clever means to cook perfect rice every time, regardless of variables such as the kind of rice, altitude, initial temperature of the water, and the exact quantities of rice and water (within reasonable limits) put into the cooker.  Here is a Technology Connections video about how they did it.

Like the elegant toaster I discussed on 2019-04-24, there is no microprocessor, sensors, or complex mechanism.  It’s as simple, and reliable, as the properties of magnetism in metals and phase transitions in water.  I’ll not spoil the genius of the design, which is revealed toward the end of the eleven minute video.

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Author: John Walker

Founder of Ratburger.org, Autodesk, Inc., and Marinchip Systems. Author of The Hacker's Diet. Creator of www.fourmilab.ch.

8 thoughts on “Rice Cookers: They Do it with a Magnet!”

  1. 10 Cents:
    A rice cooker is one of the best tools to have in the kitchen because it is so easy to use.

    Yes, but so is the tenderising hammer and rolling pin, and they have so many other uses….

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  2. John Walker:

    10 Cents:
    A rice cooker is one of the best tools to have in the kitchen because it is so easy to use.

    Yes, but so is the tenderising hammer and rolling pin, and they have so many other uses….

    Do you have any evidence of your prior “cooking” with those tools?

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  3. 10 Cents:

    Phil Turmel:
    That is elegantly simple.

    Was this a Japanese invention? The video was unclear.

    Seriously, to the Japanese, rice is a staple food. Now as to how it works, the trigger metal is designed to have such a chemical makeup that it will be attracted to a magnet up and slightly beyond the temperature of boiling water. 210 degrees Fahrenheit or 100 degrees Celsius. Under those conditions, as I see it, the molecules of the trigger metal are aligned and will correspond to the field of an external magnet, above the set temperature the molecules become misaligned  and do not respond well to a magnetic fields so the trip metal disengages from the magnet and the switch turns off the heater.

    Out of necessity, or trying to make life easier for the Japanese cook, chef or wife, it was designed.

    Actually pretty clever!

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