Pressure cooking is the process of cooking food, using water or other cooking liquid, in a sealed vessel, known as a pressure cooker. Pressure cookers are used for cooking food more quickly than conventional cooking methods, which also saves energy.
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 cooking can be used for quick simulation of the effects of long braising or simmering.
Almost any food which can be cooked in steam or water-based liquids can be cooked in a pressure cooker.
In 1679, the French physicist Denis Papin, better known for his studies on steam, invented the steam digester in an attempt to reduce the cooking time of food. His airtight cooker used steam pressure to raise the water's boiling point, thus resulting in a much quicker cooking. In 1681, Papin presented his invention to the Royal Society of London, but the Society's members treated his invention as a scientific study. They granted him permission to become a member of the Society afterwards.
In 1864, Georg Gutbrod of Stuttgart began manufacturing pressure cookers made of tinned cast iron.
In 1919, Spain granted a patent for the pressure cooker to Jose Alix Martínez from Zaragoza. Martínez named it the olla exprés, literally ""express cooking pot,"" under patent number 71143 in the Boletín Oficial de la Propiedad Industrial.In 1924, the first pressure cooking pot recipe book was published, written by José Alix and titled ""360 fórmulas de cocina Para guisar con la 'olla expres,'""or 360 recipes for cooking with a pressure cooker.
In 1938, Alfred Vischer presented his invention, the Flex-Seal Speed Cooker, in New York City. Vischer's pressure cooker was the first one designed for home use, and its success led to competition among American and European manufacturers.At the 1939 New York World's Fair, National Presto Industries, which was then known as the ""National Pressure Cooker Company,"" introduced its own pressure cooker.