What is a pressure cooker and what does it do?

One of the most effective ways to cook food is by use of a pressure cooker. Originally invented in the 1600s by Denis Papin, a resident of France, the basic concept of a pressure cooker involves the use of steam pressure within a sealed pot to cook food more quickly. Although it has taken centuries to perfect this concept into a safe and efficient practice, the original method of using steam pressure in the food preparation process remains unchanged.

Process of Pressure Cooking

The process of pressure cooking involves placing uncooked food and water into a sealed pot. Once the pot is heated, the water turns into steam and is unable to escape, placing 8 to 15 pounds per square inch of pressure on the food, cooking the food at a fast rate. The environment generated cooks the food with moist heat, ideal for making meats more tender and soups and sauces more delicious.

Conventional/Passive Pressure Cookers

Conventional or passive pressure cookers are not heated within the pressure cooker itself but instead rely on heat from an outside source, usually a stove. These types of pressure cookers usually contain a handle, attaching the lid to the pot, and have two different valves on the handle for different aspects of cooking food. One of the valves regulates the amount of pressure to be applied to the food, ranging from lower pressure settings around 8 pounds per square inch to higher pressure settings around 15 pounds per square inch. The other valve is a safety feature and will pop up to release excess steam if too much steam pressure is being applied to the pot. To trap the steam, pressure cookers contain a rubber sealing gasket around the inside of the lid to keep the steam from escaping.

Electric Pressure Cookers

Electric pressure cookers do not need outside sources of heat to operate, but instead, use electricity to heat the cooker itself. These pressure cookers also utilize both a heating valve and safety valve like conventional pressure cookers, and also contain a rubber sealing gasket around the inside of the lid to prevent steam from escaping. Electric pressure cookers essentially regulate themselves, and unlike conventional pressure cookers, do not have to be constantly monitored to make sure that outside heat sources aren’t fluctuating to negatively affect the food cooking process or causing too much steam pressure on the device itself.

Process of Using a Conventional Pressure Cooker

Set pressure cooker on an outside heating source, preferable a stove
Place food inside the pressure cooker
Place water inside the pressure cooker, adhering to the amount specified by the pressure cooker
Place the lid over the pressure cooker
Rotate and lock the lid
Set the pressure valve to the specific pressure setting for cooking the food
Turn on the stove on a high setting to bring the water to boiling
When the safety pressure valve pops, turn down the stove to a medium setting appropriate for prolonged pressure cooking
Cook food for the specified amount of time needed, keeping a careful watch on the pressure cooker and outside heating source to make sure that excessive amounts of pressure do not build up
If there is a small amount of liquid in the pressure cooker, enact a quick pressure release and open the lid
If there is a large amount of liquid in the pressure cooker, wait until the steam is released through the safety pressure valve before opening

Process of Using an Electric Pressure Cooker

Properly rotate the metal plate containing the rubber sealing gasket so that the nob on the metal plate is not obstructing the pressure regulating valve
Place food inside the pressure cooker
Place water inside the pressure cooker, adhering to the amount specified by the pressure cooker
Place the lid over the pressure cooker
Rotate and lock the lid
Set the timer on the pressure cooker for the specified time needed to cook the food
Set the specific pressure setting for cooking the food
Turn off the pressure cooker when the food is done cooking
If there is a small amount of liquid in the pressure cooker, enact a quick pressure release and open the lid
If there is a large amount of liquid in the pressure cooker, wait until the steam is released through the safety pressure valve before opening

https://www.thekitchn.com/a-primer-on-pressure-cooking-193715