There are a number of appliances that can turn off automatically, and a rice cooker is one of them. How does this work? A container with boiling water maintains a constant temperature (212 degrees F /100 degrees C at sea level). When all the liquid has evaporated or, in the case of the rice cooker, as soon as all of the water is absorbed by the rice, the temperature inside the container immediately rises. A thermostat within the appliance can detect when the temperature rises above water's boiling point, and it turns itself off.