Ever wonder how a rice cooker works or how does a rice cooker know when the rice is done cooking? The answer lies in the way a rice cooker is made and in the way boiling water is absorbed in food.
A rice cooker contains a rice pan (a container) to hold the rice and water. A heating element to heat the food, and a lid with a small hole to release excess steam. A small temperature sensor is hidden in the bottom of the rice cooker. When the water in the rice pan begins to boil, the temperature of the food stabilizes at 212 degrees Fahrenheit. As the water boils, the rice absorbs the steam and some steam escapes through the lid. When the water is nearly all gone, the temperature of the food will begin to rise above 212 degrees. This change in temperature is monitored by the temperature sensor inside the rice cooker and triggers a switch to turn the cooker off.
Some rice cookers like neuro fuzzy logic rice cookers (a popular example is the zojirushi brand) are more sophisticated and will adjust the amount of heat based on the amount of water, and the amount of heat absorbed by the food. If too much water has been added to the rice pan, these rice cookers can adjust the heat to compensate. Most rice cookers however, do not have this feature.
I found a video on Youtube by Neil Bertran who describes how a rice cooker works. You may find it useful.
