In this paper, we upgrade the mathematical model for pressurized rice cooking developed in our previous work by investigating the boiling and the steam generation process in detail. To understand the physical phenomenon of pressurized rice cooking, we measure the internal pressure by a durable data logger and estimate the valve operation from the driving signals of the stepping motor. To improve the model accuracy based on these data, we focus on the pressurized boiling phenomenon. We show the simulation results to evaluate the effectiveness of the proposed model.