Rice automatic cooker is a common cooking appliance in Asian kitchen. From ancient time, rice had been cooked either in source pan, large wok or deep pot. All has same principle : adding water to rice, bring it to boil, water will be absorbed into rice or evaporate during cooking; cooked rice is dry and soft.
The main types of rice cooker parts include electrical, sensor, controls and containment components, which vary in complexity depending on the functionality desired from the cooker. All of these components work together, with the controls dictating how and when the cooker should run, the sensor detecting temperature and completeness of cooking, the electrical components providing the current necessary for heat, and containment components holding in the food and moisture. Peripheral components allow the cooking of foods other than rice.
Automatic rice cooker use electrical power to cook rice. Add rice and water to cooker per predetermined ratio. Too much water will made cooked rice mushy, too little will result in undercooked rice. On cooker power. Cooking time is determined by a control device, either timer or temperature sensor.
Timer is less popular as it is troublesome. Timer keep rice cooked for a set time and will turn power off when it reach set time. This timing is predetermined by experiment. Rice cooking may not turned out as expected as heating devise may ware out so heat is reduced. Also changing rice variety or cooking amount will affect cooking time.
Temperature sensor is more popular. When cooker is turned on, thermal sensor will monitor cooking temperature. As water boil at 212 deg F so cooker will have temperature not higher than 212 F while rice is still wet with water. Immediately after water dry up, cooker temperature will rise above 212 F so cooker will turn off. As temperature in cooker is still high, some excess water will be absorbed or evaporated, leaving perfect cooked rice. Amount of water is important in this cooker as it determines cooking time. Thermal sensor cooker is a more accurate cooking as it indirectly check on the amount of water left in rice.