Pressure cooking is a method of cooking in a sealed vessel that does not permit air or liquids to escape below a preset pressure. Because the boiling point

Boiling point

The boiling point of an element or a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid....

 of water increases as the pressure

Pressure

Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...

 increases, the pressure built up inside the cooker allows the liquid in the pot to rise to a higher temperature before boiling.

Pressure is created at the beginning by boiling a liquid, such as water or broth, inside the closed pressure cooker and then trapping the steam.