This is How a Rice Cooker Knows When the Rice is Ready

Have you ever thought about how a rice cooker works? What goes into the perfect rice? I hadn’t put much thought into it until a friend marveled at the ease in which my rice cooker finished cooking rice. She had always used the stovetop method.

I had been rushing around the kitchen trying to get dinner on the table. I needed rice cooked in a hurry. Without much thought I added the rice to the pot, added the appropriate amount of water, closed the lid, and pushed down the lever.

My friend’s comment stayed with me, so I decided to find out exactly how rice cookers know when the rice is ready.

The Heating Element

The heating element is the part of the pot that heats the water to cook the rice. It’s controlled by the on/off button or cook/warm lever, depending on the type of rice cooker you have. In most models, you’ll see it as a raised disk inside the outer pot. Once you’ve placed the inner pot inside, the disk will drop when you push the button or lever to cook, and it will pop up once the sensor tells it to stop heating.

The Thermocouple Sensor

All rice cookers, whether powered by gas or electricity, contain a thermocouple sensor that kicks off the heating element once the inside of the pot reaches a certain temperature.

Since water boils at 212 degrees Fahrenheit (and 100 degrees Celsius) at sea level, the sensor knows that once the temperature goes above the boil temperature there’s no more water in the pot. The rice has absorbed all the water.

This is when the sensor tells the heating element to turn off, although some rice cookers keep the rice warm. In that case the heating element has been programmed to maintain a steady temperature until someone unplugs the cord or turns off the rice cooker in another way.

So that’s a basic explanation of how a rice cooker works, but there are other factors to consider when cooking rice.

Water Amount

Whether your rice cooker is a simple model or it has all the snazzy bells and whistles, none of that matters if you don’t know how to control the water. This is crucial.

Too much water and you’ll get a soggy, mushy mess reminiscent of porridge. Too little water and you get undercooked grains and possibly a burned pot! Trust me—scrubbing a burned pot is not a fun way to spend your evening.

Other Advice

Here are some other tips I’ve discovered in all these years of cooking rice.

  • Make sure to follow the manufacturer’s instructions, particularly as you add more rice. The water to rice ratio changes, so pay attention.
  • Different types of rice require different cooking times. Preparation also varies. For instance, brown rice takes twice as long as white rice to cook. You’ll need to soak it in water to soften the bran. If you don’t take care to prep your brown rice properly, you’ll end up with a foaming mess.
  • Don’ forget to unplug the rice cooker. Leaving it on the warm cycle for too long can dry out your rice.

So there you have it.  Knowing about how the thermocouple senses the water temperature takes a bit of the mystery out of cooking rice, but it’s so much more convenient than the stovetop method.