On the food
The principle involved in a pressure cooker is that increasing the pressure inside the cooker raises the boiling point of water, allowing food to cook at higher temperatures and reducing cooking time. This results in faster cooking and tenderizing of tough cuts of meat.
If you are referring to cooking with a pressure cooker, the higher pressure attained in this type of cooker allows the water to reach a higher temperature before boiling. This will cook food more quickly due to the higher temperature, which in turn is due to the higher pressure. Keep in mind that once water reaches the boiling point, the temperature remains constant; the only way to attain a higher temperature, then, is to increase the pressure.
Higher than 100°C, typically around 121°C at 1 bar pressure. The higher pressure inside a pressure cooker raises the boiling point of water, allowing food to cook faster.
Above 100 deg C The extent to which the temperature is higher than 100 deg C depends on the pressure inside the cooker and that is controlled by the weights on the cooker valve.
The higher the amount of heat the faster the food is cooked. Generally speaking the temperature of water doesn't go much over 212ºF(100ºC) and at higher elevations the temperature can be less. This is because water will boil at a lower temperature if it is under less pressure. When the pressure cooker maintains the contents under pressure the water can surpass the normal boiling temperature.
The boiling point of water in a pressure cooker is higher than normal because the sealed environment traps the steam produced during boiling, thereby increasing the pressure inside the cooker. The higher pressure raises the boiling point of water, allowing it to reach higher temperatures before vaporizing. This results in faster cooking times and more intense heat, which is advantageous in many cooking applications.
increased pressure inside the cooker, which raises the boiling point of water above 100°C. This allows food to cook at a higher temperature, leading to faster cooking times.
The universal gas law states that (pressure * volume/temperature) of a gas is a constant. Hence, if the volume stays the same (as in a pressure cooker), the air in the cooker can increase in temperature beyond the boiling point of water as pressure builds up over the normal atmospheric pressure. A higher temperature means faster cooking. The above is a very simplistic view of the physics involved.
An increase in pressure allows an increase in the boiling temperature of the liquid in the cooker. At 15 psi (the highest rated home kitchen pressure cooker) the boiling temperature of water is 250 degrees F.
The ideal gas law (PV=nRT) could apply to how a pressure cooker works. As the temperature inside the pressure cooker increases, the pressure also increases due to the trapped steam, allowing for higher cooking temperatures and faster cooking times. This relationship between pressure, temperature, volume, and number of moles of gas follows the principles of the ideal gas law.
At 117°C, the vapor pressure of water is approximately 2566 Pa.