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How Does a Rice Cooker Know When the Rice is Done?


Rice is a staple dish in many households, and while we’ve cooked rice manually for centuries, the rice cooker has become the best and most favored way to get perfectly cooked rice for every meal. 

While there are different kinds of rice cookers on the market today, with our standard and simple ones versus the more advanced rice cookers with different cooking options, they all basically have the same main function: to cook delicious fluffy rice automatically and prevent undercooked rice or rice overcooking.

Curious about the cooking process of your rice cooker and how exactly it knows your rice is done cooking? Here’s how rice cookers work to give you good quality rice every time. 

How Do Rice Cookers Know When Rice is Done Cooking?

A rice cooker is a fantastic kitchen appliance that can make cooking rice an effortless task. Rice cookers come in a variety of different shapes and sizes, and each rice cooker has its own unique set of features. However, all rice cookers – whether it’s a cheap rice cooker for the basics or the best rice cooker with the most complex options – have the same three basic functions and cooking cycle: cook mode, warm mode, and steam mode. 

A rice cooker works by using a heat source to cook the rice. The rice cooker will first soak the uncooked rice in water to soften the rice grains. Then, the heating element warms up until the internal temperature rises to the water’s boiling point (212 degrees Fahrenheit). The thermal sensor of the rice cooker detects when the water boils, and the heating element will turn off to let the rice sit in the hot water and continue cooking. 

The rice cooker will then turn on again and the temperature begins to rise to reheat the water to the boiling point, with the heat and pressure being released through the steam vent. This process will continue until all the water is absorbed and the rice cooker senses that the rice is done or has finished cooking. At this point, the rice cooker will turn off the heat and switch to its warm setting. You’ll know when the rice is done when the power light indicates the rice cooker is on its warming cycle.

What is the Cooking Rice Sensor in a Rice Cooker?

A rice cooker can be as simple as an outer shell that carries the heating mechanism, thermostat or temperature sensor, and an inner metal bowl that holds the rice.

The rice and water are put inside the metal bowl that sits inside the rice cooker. The weight of the cooking bowl, water, and rice inside will push down a spring-loaded thermostat, which will allow the bowl to sit on the heating element.

When the rice cooker is turned on, the heating element heats up, boiling water in the rice cooker and creating steam. This constant temperature gradually cooks the rice as the rice absorbs the water and expands.

The temperature inside is the boiling point of water, 212 degrees Fahrenheit or 100 degrees Celsius, and the rice cooker will not go above this internal temperature as long as there is water in the dish. The spring-loaded thermal sensor at the bottom measures the temperature of the bowl and when all of the water in the rice cooker is absorbed. This indicates that the rice is done and the temperature rises, the rice cooker turns off and will stop cooking, and the indicator light will move to warm mode.

Most rice cooker bowls are made of aluminum because it is a low-cost metal that transfers heat very effectively. They can have a non-stick coating which makes it easier to remove the rice when it is done.

Why Does My Rice Burn or Get Dry in the Rice Cooker?

While cooking rice in a rice cooker should mean good quality rice, some of us may experience burnt or dry rice. 

Burnt rice can be a result of not washing your rice before putting it in the rice cooker. Excess starch that remains on your rice causes grains to stick together and cook unevenly, resulting in uneven or even burnt rice.

On the other side of things, your rice may come out of your rice cooker dry because you aren’t putting enough water, especially for different rice types. Brown rice, for example, requires twice as much water as white rice.

What Kind of Rice Cooker Should I Get for Perfectly Cooked Rice?

If you cook rice regularly, a rice cooker is definitely a worthy investment. Now that you know the answer to “how does a rice cooker work?” or “how does a rice cooker know rice is done?” you can figure out what kind of rice cooker best suits your needs.

While pretty much all types of rice cookers on the market can give us perfect rice, the right type of rice cooker for you will depend on what you need from it. Traditional rice cookers are simple and very user-friendly, with only one purpose: to cook rice just right. Usually, this type of rice cooker will only come with a steaming tray as an add-on.

On the other hand, high-end rice cookers allow us to cook other foods than rice, and also have special settings for brown rice, wild rice, and rice pudding, telling us whether we need twice as much water as white rice and automatically setting the right cooking time for each rice type.

Final Note

While we have many different appliances today to help us cook our food, from pressure cookers and slow cookers to Instant Pots, rice cookers are versatile kitchen appliances that are perfect for those who love eating and cooking rice regularly. With a rice cooker, you can enjoy perfectly cooked rice without any hassle.

So, do rice cookers know when rice is done cooking? Thanks to the internal thermal sensor, the cooking time of your rice will always be exact to give you perfect rice. In the case of a rice cooker, the thermostat turns on the heating element when the water inside reaches 212 degrees Fahrenheit and turns it off again when the required cooking time has elapsed. This is how your rice cooker knows your rice is done and good enough to eat.


Hailing from California, USA. Ji-hyun is a Korean American 🇰🇷🇺🇸 with two growing boys who eat their weight in rice each week. After graduating UCLA & becoming a mom she started We Know Rice as a guide for all the students and moms out there looking to cook healthy and filling meals.

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