Pressure Cooker
`text(Principle :)`
The basic principle is that food cooks faster at higher temperature.
The governing law in Physics is Gay-Lussac's Law: The Pressure Temperature Law. This law states that the pressure of a given amount of gas held at constant volume is directly proportional to the Kelvin temperature. As the pressure goes up, the temperature also goes up, and vice-versa.
`text(How do Pressure Cookers Work ?)`
Normally water will boil at `212^@F(100^@C)` at sea level atmospheric pressure at 1,01325 bar, i.e. normal atmospheric pressure on the sea level at `0°C` -'in an open system'. At this temperature liquid water turns to gas. Applying more heat to an open pot of water will only increase the rate that liquid water turns to vapor but will not increase the temperature of the liquid.
If the pressure is decreased (e.g., at higher elevations) the point that water boils will be decreased (since it is easier for water molecules to escape the surface). If we increase the pressure on water it becomes more difficult for water molecules to escape the surface and a higher temperature is required for the water to boil.
In a closed container things change. The water and vapor are in equilibrium and will maintain the same temperature. With no place to escape if heat is applied to the closed container the molecules in the gas state will increase velocity, hence temperature. This will increase the pressure on the surface of the liquid. And, the temperature of the water system will then increase.
`text(Parts of Pressure Cooker and their Functions :)`
`text(1. Pressure Regulator :)` The pressure regulator controls and maintains 15 pounds of pressure in the pressure cooker. This is the ideal cooking pressure and is obtained when the pressure regulator begins a gentle rocking motion. When purchasing a pressure cooker, choose one that operates at 14-16 pounds per square inch or PSI when it reaches high pressure. This will be the fastest type of cooker to use.
`text(2. Vent Pipe :)` The pressure regulator fits on the vent pipe and allows excess pressure to be released if needed.
`text(3. Air Vent/Cover Lock :)` The air vent/cover lock automatically "vents" or exhausts air from the pressure cooker and acts as a visual indication of pressure in the pressure cooker. When the air vent/cover lock is in the up position, there is pressure in the unit. When it is in the down position, there is no pressure in the unit.
`text(4. Lock Pin :)` The lock pin, located on the cover (or lid) handle, engages with the air vent/cover lock to prevent the cover from being opened when there is pressure in the unit.
`text(5. Sealing Ring :)` The sealing ring fits into the pressure cooker lid and forms a pressure-tight seal between the lid and the body during cooking.
`text(6. Over-pressure Plug :)` The over-pressure plug is located in the lid. It will automatically release steam in case the vent pipe becomes clogged and pressure cannot be released normally.
`text(7. Cooking Rack :)` The cooking rack is placed on the bottom of the pressure cooker for steaming foods. It also holds foods such as vegetables out of the cooking liquid which allows the cooking of several different foods at the same time without any intermingling of flavors. When it is desirable to blend flavors, do not use the cooking rack.
The basic principle is that food cooks faster at higher temperature.
The governing law in Physics is Gay-Lussac's Law: The Pressure Temperature Law. This law states that the pressure of a given amount of gas held at constant volume is directly proportional to the Kelvin temperature. As the pressure goes up, the temperature also goes up, and vice-versa.
`text(How do Pressure Cookers Work ?)`
Normally water will boil at `212^@F(100^@C)` at sea level atmospheric pressure at 1,01325 bar, i.e. normal atmospheric pressure on the sea level at `0°C` -'in an open system'. At this temperature liquid water turns to gas. Applying more heat to an open pot of water will only increase the rate that liquid water turns to vapor but will not increase the temperature of the liquid.
If the pressure is decreased (e.g., at higher elevations) the point that water boils will be decreased (since it is easier for water molecules to escape the surface). If we increase the pressure on water it becomes more difficult for water molecules to escape the surface and a higher temperature is required for the water to boil.
In a closed container things change. The water and vapor are in equilibrium and will maintain the same temperature. With no place to escape if heat is applied to the closed container the molecules in the gas state will increase velocity, hence temperature. This will increase the pressure on the surface of the liquid. And, the temperature of the water system will then increase.
`text(Parts of Pressure Cooker and their Functions :)`
`text(1. Pressure Regulator :)` The pressure regulator controls and maintains 15 pounds of pressure in the pressure cooker. This is the ideal cooking pressure and is obtained when the pressure regulator begins a gentle rocking motion. When purchasing a pressure cooker, choose one that operates at 14-16 pounds per square inch or PSI when it reaches high pressure. This will be the fastest type of cooker to use.
`text(2. Vent Pipe :)` The pressure regulator fits on the vent pipe and allows excess pressure to be released if needed.
`text(3. Air Vent/Cover Lock :)` The air vent/cover lock automatically "vents" or exhausts air from the pressure cooker and acts as a visual indication of pressure in the pressure cooker. When the air vent/cover lock is in the up position, there is pressure in the unit. When it is in the down position, there is no pressure in the unit.
`text(4. Lock Pin :)` The lock pin, located on the cover (or lid) handle, engages with the air vent/cover lock to prevent the cover from being opened when there is pressure in the unit.
`text(5. Sealing Ring :)` The sealing ring fits into the pressure cooker lid and forms a pressure-tight seal between the lid and the body during cooking.
`text(6. Over-pressure Plug :)` The over-pressure plug is located in the lid. It will automatically release steam in case the vent pipe becomes clogged and pressure cannot be released normally.
`text(7. Cooking Rack :)` The cooking rack is placed on the bottom of the pressure cooker for steaming foods. It also holds foods such as vegetables out of the cooking liquid which allows the cooking of several different foods at the same time without any intermingling of flavors. When it is desirable to blend flavors, do not use the cooking rack.