While the fear of Grandma’s old pressure cooker exploding might have you avoiding these kitchen tools, modern ones are quite safe and allow food to cook far faster than traditional stove top methods. The simple science behind this enables foods to tenderize and moisturize more efficiently, while cutting cooking times significantly.
Pressure cookers are able to radically cut cooking times for foods like beans, whole grains and stews. This is because they create high-pressure cooking environments inside their tightly sealed pots. This high-pressure environment boosts boiling temperatures by trapping water molecules in a way that doesn’t allow them to escape.
This raises the temperature at which chemical reactions happen, including those that break down tough meat and soften starches. It also increases the rate at which those reactions occur. That’s why food cooks faster in a pressure cooker than it does when cooked on the stovetop or in an oven.
But you must use a pressure cooker correctly to ensure the safety of your food. Modern ones feature built-in safety mechanisms to prevent them from accumulating too much pressure. They typically have a countdown that alerts you when they’ve reached the required level of pressure and then automatically turn off the heat source. If you try to open the lid before the timer goes off you could be scalded.
You also need to be sure to add the right amount of liquid to your recipe – most instructions tell you the minimum needed for pressure cooking. The liquid is necessary to produce the steam that raises the boiling point, allowing your food to cook faster. If you don’t add enough liquid your meals will be mushy and may not reach the desired consistency.
A pressure cooker works by bringing water to a boil under the force of steam. The pot is sealed tightly so that the steam can’t escape, which raises its atmospheric pressure and causes the boiling point to rise. This increased pressure allows food to be cooked at higher temperatures, which cuts cooking time and energy.
Pressure cooking also makes foods more moist, which speeds up the rate of water evaporation and helps the food absorb heat faster. Its sealed environment prevents nutrient loss, so foods retain more vitamins and minerals compared to other common cooking methods like boiling or steaming.
This pressurized environment does more than just raise the boiling point, it also creates intense heat that breaks down tough molecules and rapidly tenderizes meats and vegetables. It’s because of this high-heat, high-pressure method that many recipes’ cooking times are halved when using a pressure cooker.
Boiling is the most common cooking method, but it can take a long time to bring water to a boil and can cause some foods to lose nutrients. Pressure cooking, at the same temperature of 1 bar/15 psi, cooks food in half the time as boiling and saves energy. It also helps to preserve around 90% of nutrients like minerals and vitamins compared to 75% with steaming and 40% when boiling.
With less water or liquid in a pressure cooker, the steam is able to transfer energy much more quickly to food. This, combined with the higher cooking temperature, speeds up most foods’ cooking times by a good margin.
Additionally, at the higher pressure, the boiling point of water rises. While water still boils at 212 degrees Fahrenheit in a conventional pot, at the higher pressure it can reach a boiling point of over 250 F.
In fact, a well-maintained pressure cooker can cook many foods in half or a third of the time it would take on a stove top or in an oven. For example, a typical pot of beans can be ready in about an hour, while on the stovetop they can take more than three hours to cook until tender.
A pressure cooker can also be used to make nutrient-rich stocks in about an hour, versus the better part of a day it takes on the stovetop. And it can turn tough cuts of meat full of connective tissue into fork-tender, savory gelatin in about a quarter of the time it would take on the stovetop to render them.
A pressure cooker can save a lot of time and energy for the home cook, but it’s also useful in restaurants and other businesses that need to serve large quantities of food to customers in a short amount of time. And while the pressure cookers of decades ago tended to explode, modern electric and manual models are designed with safety valves that can reduce the pressure inside when it becomes dangerously high.
Unlike slow cookers that cook foods for long periods of time at low temperatures, pressure cookers make quick work of dishes that need to be cooked at high heat. This cuts cooking times by up to 50% and helps tenderise cheaper cuts of meat. It also allows people to eat nutritious meals like beans and whole grains even on weeknights.
The key to a pressure cooker’s effectiveness is its hermetically sealed environment. When you put food into the pot, a thick layer of inescapable steam is trapped and the atmospheric pressure is boosted up to about 1 bar (15 psi). At this pressure, boiling temperature rises from 100 degrees Celsius to between 121 and 250 degrees Celsius.
In this sterile, steamed atmosphere, chemical reactions take place more quickly and the food is cooked at much higher temperatures. This means that you can use less water to cook food in a pressure cooker because it will be heated faster and retain its liquid form longer.
The downside of this is that pressure cookers aren’t good for achieving crispy or crunchy textures, so don’t try making breaded chicken or frying anything in one. They are also not the best for milk and other dairy products that tend to curdle at high temperatures. For these reasons, it’s important to follow safe guidelines when using a pressure cooker.