45 minutes. The principle of pressure cooker is to exert pressure on water through the physical phenomenon that the boiling point of liquid will rise under higher air pressure, so that the water can reach a higher temperature without boiling, thus accelerating the efficiency of stewing food, so beef can be pressed in pressure cooker for about 45 minutes. Pressure cookers are aluminum and aluminum alloy pressure cookers, and their surface colors can be divided into white, light yellow and other colors. Before adding the pressure limiting valve, it is also necessary to check the air holes on the pressure limiting valve. You can detect it by blowing into the big hole with your mouth. If the air hole is found to be blocked, it can be used after being poked open with a thin wire. The earliest name of the pressure cooker was Pap Ping Guo, which was invented by a French doctor named dennis Papin. At first, it was only used as a disinfectant.