Pressure cooking is the process of cooking food in a sealed vessel (known as a pressure cooker) that does not permit air or liquids to escape below a pre-set pressure. Pressure cooking allows food to be cooked with greater humidity and higher temperatures than possible with conventional boiling or steaming methods. In an ordinary non-pressurised cooking vessel, the boiling point of water is 100 °C (212 °F) at standard pressure; the temperature of food is limited by the boiling point of water because excess heat causes boiling water to vaporize into steam. In a sealed pressure cooker, the boiling point of water increases as the pressure rises, resulting in superheated water. Pressure is created initially by boiling a liquid such as water or broth inside the closed pressure cooker. The trapped steam increases the internal pressure and temperature. After use, the pressure is slowly released so that the vessel can be safely opened. Pressure cookers heat food quickly because the internal steam pressure from the boiling liquid causes saturated steam (or “wet steam”) to permeate the food. This results in faster cooking times compared to conventional cooking methods because liquids and steam conduct heat more rapidly than dry air.