You breeze through cooking today thanks to a plethora of electronic or mechanical devices; they reduce your time and effort in preparing food. Yet, all through history, cooking has been one of the most demanding tasks, which often wearied people, who tended to the hearth at homes, bakeries, factories and hotels.
The invention of pressure cookers
In 1679, Denis Papin, a French physicist famous for his experiments with steam, invented a ‘steam digester’. This was a thick and airtight vessel; it used steam pressure to raise the boiling point of water, and cooked faster the immersed food. When Papin presented this invention to the Royal Society of London, it was recognized as a scientific innovation. The device was used for a few decades at some inns and then quickly forgotten.
It took another two centuries before German entrepreneur George Gutbrod began manufacturing pressure cookers in 1864. A variation of Papin’s device, it was bulky and difficult to handle. In 1918, Jose Martinez, a Spaniard, designed a more compact ‘express cooking pot’ for which he received a patent. After that, there was no looking back and the world began to take pressure cookers more seriously.
The basic principle of creating steam pressure and regulating it to cook food has remained constant. However, the mechanisms used to generate steam and regulate pressure have changed in the last hundred years. So also, the materials used in pressure-cookers have seen some innovation. All such innovations can accordingly be divided into three types:
- First generation: These devices have a ‘jiggly valve’, a weighted mechanism that moves up and down as pressure builds up; it is displaced significantly to release pressure. The only innovation in this type is the availability of two or more weights, depending on the kind of food cooked or the degree of pressure required.
- Second generation: These gadgets have a pressure-loaded spring valve with multiple pressure settings to regulate pressure. Unlike the first generation cookers, which release steam to regulate it, these cookers do not release steam in the normal course of cooking; they indicate just the pressure built inside, so that you can turn off the heat.
- Electric Cookers: While the above two types were stovetop, or kept on a stove to get heated up, electric cookers use a heating coil to heat the water and generate steam. A pressure-loaded spring valve regulates pressure as in second-generation cookers. These cookers come with a timer to delay or program the cooking.
While stainless steel cookers are widely preferred, aluminum and copper-bottom cookers are also prevalent. Other innovations indicate to the user the way pressure is released, the way air is expelled from the cooker, and the way pressure changes.
Other variations include autoclaves used in laboratories to sterilize equipment, pressure canners for home canning of food, and pressure fryers for pressure-frying meat.
Pressure cookers conserve energy, as the time/heat required to cook food is much less. Furthermore, they work at temperatures above the boiling point of water, thereby killing microorganisms and rendering the food safe. All these factors have made pressure-cooking the most preferred mode to cook most of the foods we consume today.