The pressure cooker

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 of water increases as the pressure 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 with boiling liquid, such as water, inside the closed pressure cooker and the trapped steam increases the internal pressure and temperature, which is maintained throughout cooking time.

An early pressure cooker, called a steam digester, was invented by Denis Papin, a French physicist, in 1679. Large pressure cookers are often called pressure canners in the United States, due to their capacity to hold jars used in canning. A version of a pressure cooker used by laboratories and hospitals to sterilize materials is known as an autoclave.