A pressure cooker is a cooking appliance that uses both heat and pressure, usually in the form of trapped steam, to cook food. The basic concept behind pressure cooking has been around for centuries. The simplest models are little more than pots with locking, tightly sealed lids that can be placed in fires or primitive ovens. More modern versions are designed to sit on the stove, though they can also be electric. They typically have pressure gauges and valves that allow for customized cooking, and settings can usually be changed depending on the ingredients. Some people also use these tools to preserve food in cans, usually as an alternative to water bath canning. Depending on the device, releasing the pressure can require a bit of finesse, and there are usually a couple of options depending on the desired outcome. Though these appliances are usually safe when used as directed, they can present a range of dangers when used inappropriately. Reducing risks of burns and explosions usually requires attention to details and common sense, as well as a firm understanding of how the device works before beginning.
Core Components and How it Works
In general, the main goal of any pressure cooker is to allow people to prepare foods in less time than required by conventional methods. Soups and stews that might need hours to simmer can take as little as 15 minutes in one of these devices, and they’re also a popular way to tenderize meats and soften vegetables. Many of the traditional recipes of cultures in high altitudes, for instance Andean communities in South America, rely on pressure to reduce what would otherwise be extraordinarily long cook times.
A typical pressure-based cooker comes in the form of a large pot that includes a locking lid. Once water or some other liquid inside the pot reaches a boil, the steam, unable to escape, becomes compressed. Water typically boils at 100°C (212°F) but when it is under pressure, the boiling point rises to about 121°C (250°F). This higher temperature drastically reduces cooking time and the moist steam serves to tenderize the other ingredients, anything from dense meats to whole vegetables. The effect mimics what happens when these foods are allowed to slowly simmer for hours on end: the proteins break down and the flavors release. Most of the dishes cooked in these sorts of devices taste like they’ve been cooking for hours.
Very traditional pressure vessels are usually simple pots with locking lids. These require the person cooking to pay attention to timing and external heat in order to know when the food is done; much of this is learned through experience or is handed down from other family members. Modern appliances sold for use in standard kitchens often have more in the way of measurements and readers that can allow users to specify different settings or temperatures. As such, people can adjust for foods of different weights or densities, and can accommodate for the addition of ingredients that are frozen or already partially cooked.
For Day-to-Day Cooking
Pressurized cookers can be used to prepare a wide variety of foods. Some of the most common are soups and stews, meals that would otherwise need a lot of time to simmer in order to achieve the right flavor, but vegetables and even certain pastas are also good choices.
As a Means of Preserving
Sometimes people also use their cookers as a way of preserving foods, essentially using the pressure to seal bottles and jars of sauces, jams, or fruits and vegetables. Pressure canning is usually recommended for foods with a high acid content, like tomatoes. Canning these foods in ordinary water baths may not get them hot enough to kill harmful bacteria, which can make the end results dangerous to consume. While canning in a pressure cooker can work, most experts don’t recommend it. A separate appliance known as a pressure canner is usually safer and easier to use.
Releasing the Pressure
Commercially produced cookers usually come with an instruction booklet at outlines a couple of different ways to release pressure and thereby finish the cooking process. This can be dangerous, as the steam that’s released is usually extremely hot. In general, there are three main methods: the cold water method, which requires slowly pouring cold water over the outer surface of the cooker; the manual method, in which users open the lid or release a valve to allow the steam out all at once; or the natural method, in which the device is removed from heat and allowed to cool on its own. Each has advantages and disadvantages, and choosing one is often a matter both of the food being cooked and personal preference.