How an automatic rice cooker works

I would like to posit that penning a long monologue with sarcastic flourishes as the first sentence is shit writing.

Also people who think cooking rice is difficult are inept.

Electric pressure cookers are actually descended from electric rice cookers. The fancier sealed lid kind like your zojirushi, not the crock pot kind in the video. Basically you start from the sealed lid and very slight pressure in the rice cooker, and track the pressure up and add functions over time. And you got an Instant Pot.

So they tend to be really good at cooking rice.

It has never worked for me. What does is the craggy rice method.

So basically the same but 2:1 water to rice.

Crack the lid heat at max.

Turn down once it’s boiling to prevent boil over, but keep it boiling. Until the level of the water falls below the surface of the rice, leaving no visible liquid at the surface and the titular craggy top.

Close the lid, remove from heat. Let sit for 5 minutes covered.

Seems to work for all rice, washed or not. Provided you don’t forget about it until all the water boils off. Where in it will be alternately mushy on the bottom or scorched on the bottom depending on how late you got to the “oh shit” moment.

I want a rice cooker because I have too many “oh shit” moments.


I’m asking myself, did I really make it 42 years without knowing that ferromagnets will lose their magnetism when heated to a specific point? Maybe I learned this decades ago and forgot it, or maybe I just never knew. Huh!


Every time I use my rice cooker, I wonder about that button, and what part it plays in the dance. I’m so happy to finally get my itch scratched! I knew somehow that the answer would seem simple and elegant and clever, what I didn’t know, was that the physics of the curie point was involved. Thanks!


Not having seen this video, I think we need something similar for electric pressure cookers because I’m pretty sure they don’t actually detect pressure, just temperature.

I got halfway through the video this time. I’m improving.

A similar explanation?

Pressure cookers need not detect anything, they use a valve that opens when they hit a given psi. And a gasket that lets air out, that locks when the pressure gets high enough. It’s all mechanical.

Different valve for different pressure settings. And since temperature is directly connected to the pressure, based on the way it alters the boiling point of water. You wouldn’t have to worry about temperature anyway. It’s a direct factor of whatever pressure you’re set at.

Whole idea is that as pressure rises above ambient, the boiling point tracks up in tandem.

Cooking in liquid you can’t cook higher than the boiling point of water at ambient pressure (212f/100c at sea level). Increase the pressure and you increase the temp. Higher temps cook faster. So the pressure cooker cooks faster.

This is also why food cooks slower at high altitude.

The 15psi of a standard stove top cooker on high puts the boiling point at 250f at sea level.

And its just valves and gaskets. That’s why you can have a completely analog pressure cooker you stick on a burner.

The electric ones do it the same, and they don’t really need to detect anything. The pressures and temps are fixed. Which pressure level is programmed in for preset/programmed functions. At most they might need to know if the valve tripped so they can toggle the heat and off to maintain pressure without boiling off too much liquid. But you could do that with a simple switch.


I really enjoy this topic and your post, but seeing psi used in 2020 gives me the willies.


When the pot boils reduce heat to minimum, and set the timer for 17 minutes (near sea level).

Sure is a good thing all stoves produce exactly the same quantity of heat when you set them to ‘minimum’!
Oh wait.

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Look, you missed an obvious joke. You can either admit to it (it’s not a big deal, it happens to everybody from time to time), or you can be an asshole about it and keep blaming everybody else.

That said, this video is about the cool way a kitchen appliance is taking advantage of the curie temperature of a metal, not about the usefuleness of that particular appliance or about how superior you are to the people that does find it useful.


Quite right. We should all be indicating pressure in atmospheres, bar, or torr.

Well it’s how pressure cookers are labeled. Its also how the recipes and technical food processing instructions tend to be listed. So it’s consistent with the subject.

I think the high mark on stove tops is 1 bar. But excluding pressure canning, everything else is below that.

Thank you BB for something wonderful! We’ve used one like this for decades, and I’ve always wondered how they worked- specifically how it “knows” the rice is done, considering the only factor involved was weight and how does it know water weight vs. rice weight or if I left a wooden spoon on top. Always thought it was ingenious even without knowing how it worked, and now that I know it doesn’t take away the magic it just makes it more awesome.

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Strangely enough, Roger Ebert wrote a book about cooking in a rice cooker:

It came out of this blog post he wrote:

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If you, like me, don’t want to sit through 11 minutes of a guy talking about a simple thing, here’s the explanation:

Turn it on, the heater goes on and heats rice and water to 100 degrees centigrade, which remains more or less stable as long there’s water left. Once all the water is soaked up by the rice or evaporated, temperature jumps up, and a thermal sensor detects this sudden change and puts the heater into warming mode.

Read this for more details:


Thanks for that. I really don’t like videos, for most things text is better. I realized long ago that one reason I like newspapers over radio or tv news is I can read at my rate, and skip ahead as needed. But in this new age I actually have sampled videos, and I suspect most aren’t done well, “get to the point”.

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Oh, but what a thermal sensor it is—and how it puts the heater into warming mode!

Your facile dismissal breaks my heart!

:wink: I hope you know that I’m teasing a little, but there is more to it, and the guy explains it well. I already knew the part you tell, and I learned even more from the video :smiley_cat:

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Would the simple rice cooker in the video make brown rice? I’m assuming it would, figuring that brown rice would just take that much longer to absorb the water (at which point the rice temperature increases, the magnet does its thing etc.).

I almost never make white rice, and for that matter I don’t make brown rice very often (maybe once or twice a month), which is why I haven’t worried much about getting a rice cooker. (Though I imagine the dishes that I do cook, e.g. jambalaya and red beans and rice, would be better with white rice.)

My method for brown rice:

  1. Measure rice and rinse; place in the pot
  2. Measure slightly more than twice as much water; place in the pot
  3. Boil with the lid off, until the water level is down to the top of the rice
  4. Put the lid on, turn the heat to “low” and cook for 20 minutes
  5. Turn off the heat and remove from burner
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Yes! Deja vu, here is my answer to the same question from another user, just about one year ago, may as well just link to it :smiley_cat:

(And actually I saw my same rice cooker at the same store on sale for just $10 on their Black Friday sale.)

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I had a cheap rice cooker and never had a problem cooking brown rice. I can’t remember details about water to rice ratio. Nothing to set since the cooker checked for “properly cooked” rather tgan cooking for a certain time.

The reality is that brown or white, it always turned out right. No need to keep checking.

Though, cooking basmati rice with coconut milk was a problem, if I recall properly. I can’t remember details. I used a can of coconut milk and then water to make the total liquud but it seemed to fool the mechanism that normally knew when the rice was cooked.