Pressure Cookers are receiving a revival recently as we demand more energy efficient household appliances. A pressure cooker is a simple device, and does not need electricity to work it’s magic. In fact, pressure devices are used not only for cooking but also in laboratories for sterilizing equipment, are life-saving devices for mountaineers who would otherwise find it incredibly difficult to simply boil water at the high mountainous altitudes.
HOW DOES COOKING UNDER PRESSURE WORK?
To start the process, food is placed in the pot, then a fixed amount of liquid is added to them depending on the volume and type of food being cooked. It is this liquid that steams the food at high heat to cook it quickly and efficiently. Once the item being cooked and prescribed amount of liquid are in the pressure cooker pot, the lid is placed on the pot and locked into place, forming an airtight seal through which no liquid or steam can escape.
Pressure cookers work just as their name implies. As the liquid inside the pot begins to heat up, it starts to boil and steam is produced. In a typical non-pressurized pot, even with a lid, quite a bit of this steam will escape around the edges. Because the steam inside a pressure cooker pot cannot escape, pressure builds up inside the pot. This causes food to cook faster and more evenly in two ways.
First, pressure buildup within these pots causes the boiling water and steam to heat up more than it would in a non-pressurized environment. Boiling water (and the steam it produces) has a temperature of 212 degrees Fahrenheit. Under pressure, steam reaches much higher temperatures. Secondly, the pressure inside actually forces the steam into the food, facilitating efficient and evenly distributed heat transfer.
Pressure inside a pot has its own unit of measure called PSI, or pounds per square inch. Most recipes for them call for relatively high pressure (typically of around 15 PSI) which heats the inside of the pot to a temperature of approximately 250 degrees Fahrenheit; an increase of about 40 degrees above foods boiled or steamed in a typical kitchen pot.
Of course, if you kept boiling a completely sealed pressure cooking pot, then eventually it would explode. As many did, in fact, until someone had the handy idea of including a pressure release valve. When the pressure builds up too much, it is released.
Why cook with one?
Firstly, steam is much more effective at heating food and killing bacteria that other methods of cooking, requiring far less energy to cook that say an oven, or simply boiling something. Steam is a better conductor of heat than air – which is why you can put your hand in an oven at full blast and not get burnt, but steam from a kettle will burn quickly.
Technically, food cooked via this pressure / steam method will take 2/3rd less time than conventional methods.
Another surprising reason to cook with a pressure cooker is that the nutritional value and moisture of the food is maintained. This is because you are heating for less time, and the nutritionally rich steam doesn’t escape – most of it condenses back in the pot and stays there.
These device is safe and well-engineered. Used in accordance with the manufacturer’s directions and a hint of common sense, modern day pressure cookers work well, last a long time and do NOT blow up.
So if you’re looking to feed your family food that is more nutritious for less energy costs, you should definitely look into getting a pressure cooker. They’re not expensive at all, and you can usually pick up an old one from a charity or goodwill shop.