The time required for cooking vegetables and other foods can be greatly reduced if the boiling point of the water is raised. This can be done by the use of a pressure cooker.

A pressure cooker is sometimes known as digester. It is in use since 17th Century and was invented by a Frenchman named Denys Rapin. In an account written in 1681, Rapin described how he used the digester to extract gelatin from beef bones. He afterwards added lemon juice and sugar to the gelatin and found the resulting lemon jelly much to his liking.

The modern counterpart of digester commonly takes the form of aluminium shout fitted with a lid having a rubber sealing ring. Steam is allowed to escape through a loaded pin valve which can be set to blow at excess pressures varying from a third to one atmosphere. By this means it is possible to cook at temperatures up to 120 degrees or more, which is a saving of time and fuel.

Explorers in mountainous regions find pressure cookers indispensable and they are useful in other places where the atmospheric pressure is low or where there are extremely cool temperatures.

 A pressure cooker is a valuable item to have for cooking everything from soup, vegetables and stews. My kitchen wouldn't be the same.