A pressure cooker makes short work of cooking a roast or other tough cuts of meat that need to be tenderized. They also cook cheap ingredients like dried beans very quickly.
Modern electric pressure cookers plug in and operate with the push of a button. They’re generally safer to use than the old stovetop models that tended to explode.
Temperature
A pressure cooker increases the boiling point of water and other liquids inside it. This means it can reach a higher temperature than an open pot of boiling water at the same time, thus cooking foods faster.
The heat is also more intense under pressure, so it penetrates the food more quickly than in a traditional open pot. This makes for more even and quick cooking, especially when the food is diced so it has a greater surface area to absorb the heat.
Unlike boiling, which requires constant stirring to maintain a uniform temperature, a pressure cooker can be set and left alone. This makes for quicker cooking and easier cleanup.
It is important to note that a pressure cooker has a built in safety valve, usually a red button or valve on the lid, to prevent over-pressurization. This means that you should never overfill the pressure cooker with food or use it for recipes that call for more than one bar/15 psi (gauge) of pressure because it could damage the device and create dangerous levels of steam inside the vessel.
This is especially true for cooking at high altitudes. For example, at 5000 feet above sea level in Denver, CO, water boils at only 212 degrees Fahrenheit, so the cooking times for various foods must be increased to compensate for this.
Pressure
Pressure cookers increase the temperature at which water boils by increasing the atmospheric pressure. Since boiling point temperatures rise with pressure, your food will cook much faster than it would in a pot that’s at sea level. It also heats foods more evenly, and breaks down tough fibers in meats for tender brisket or stews.
In addition, the vapor produced in a pressure cooker is quickly transmitted to the surface of your food, killing any micro-organisms that might be present and making your cooked food safe for storage or eating. This rapid transmission of steam energy is one reason why pressure cooking is so effective at sterilizing containers, for example glass baby bottles or jam pots.
The type of container used in a pressure cooker also impacts the cooking time of your dish. If a recipe calls for a metal pot but you use a non-metal plastic or ceramic one, your food will take longer to cook. In general, recipes for pressure cookers call for stainless steel or aluminum vessels that can withstand high temperatures.
It’s important to begin heating your pressure cooker as soon as you turn it on to create a high enough level of pressure for fast cooking. Most recipes will tell you when the correct pressure has been reached and suggest a suggested cooking time. Some electric pressure cookers have a built-in sensor that detects when the appropriate level of pressure has been achieved and will automatically switch to a simmer setting.
Time
With a pressure cooker you can cut huge chunks of time from recipes, from stew to casserole and braised meat, and even make risotto in half the usual cooking time. The reason is that the boiling point of water increases with increased pressure, and at higher pressures it is much hotter.
Inside the tightly sealed pressure cooker, as the liquid heats up it turns to steam and this traps some of the air molecules around the food. This raises the pressure, and with it the temperature of the food, so chemical reactions that normally take a long time – such as breaking down tough meat or softening starch – happen very quickly indeed.
Obviously, you must have enough liquid in the pressure cooker to generate this high-pressure environment, so that is why most recipes include a minimum level of water. You also need to be careful that the pressure cooker is firmly sealed and not tampered with or moved while it’s heating up, as this could cause it to explode.
You also need to follow the instructions carefully for releasing the pressure after your meal is cooked. This is typically done using the natural release method – by leaving it off the heat source for 10 to 15 minutes and waiting for the coloured pin in the lid to drop (many modern electric pressure cookers have safety valves that prevent this from happening). It’s important to do this carefully as not doing so can leave your food overcooked.
Safety
While modern pressure cookers have many safety improvements, they can still be dangerous if not used properly. The high temperatures and fast cooking times in a pressure cooker can cause food to explode, making it imperative to use proper technique and follow the manufacturer’s instructions. In addition, the steam that is released during pressure cooking can burn or scald people handling the pot. This risk is reduced by using a pressure cooker with a stainless steel lid and a stainless steel trivet, and by keeping the pot away from counters and cabinets where it can damage these materials.
Some foods, such as beans, need to be soaked or “boiling” before they are cooked in order to soften them. This is best done in a separate pan before placing them in the pressure cooker to reduce the amount of water needed to reach pressure. Adding a small amount of water to the pressure cooker during this step will also help it cook faster.
The pressure cooker should never be overfilled and the valve must be checked to make sure it seals tightly. A leaking valve can cause the pressure inside to build up too quickly and explode, so it is important to regularly check that the gasket is sealing well and that the vent is not blocked. Some foods, like pulses or rice, can get into the valve and clog it. This can be prevented by filling the pressure cooker only half full and using a heat-safe container that fits inside the pot.
