A pressure cooker is a special pot with a lid that locks in place, creating an airtight seal. This traps moisture inside the pot and also allows pressure inside the pot to increase. Cooking under pressure gives you a number of benefits. You will be able to cook food faster while also retaining more of the food’s nutritional value, but to understand how a pressure cooker works, we need to look at a pressure cooker scientifically.
The boiling point of water at sea level is 100°C or 212°F. If you are boiling a pot of water on your stovetop, it doesn’t matter how long you leave the pot on the stove or how much you crank up the heat on the burners, as long as there is water in the pot the water will never get any hotter than 212°. Turning up the heat on the burner may cause the water to boil faster and the water will turn to steam, but the temperature of the liquid water will remain constant. The only way to heat water beyond 212°F is to heat the water under pressure and that is what a pressure cooker is designed to do.
As pressure increases, the boiling point of water also increases. A pressure cooker will typically operate somewhere between 5 PSI and 15 PSI above atmospheric pressure. Normal atmospheric pressure at sea level is 14.7 psi and with a pressure cooker, you can effectively double the atmospheric pressure. This would increase the boiling point of water from 212°F to approximately 250°F. By getting the water and steam inside the pressure cooker to reach higher temperatures, you can cook foods faster. You will be able to cook many foods in one third of the time it takes with other cooking methods.
In addition to cooking foods faster, cooking under pressure also tenderizes foods and allows flavors to mingle quickly. You will also be able to retain more of the nutrients in your food when pressure cooking than you would with other cooking methods. There was a study published back in 2007 by The Journal of Food Science that measured vitamin C retention in broccoli when using five different cooking methods. Broccoli that was cooked with a pressure cooker for 2 min. retained 92% of its vitamin C compared to just 22% vitamin C retention for steamed broccoli.
So far we have discussed how a pressure cooker works and some of the benefits of pressure cooking. There are some additional benefits that we haven’t covered yet. In addition to reducing cooking time and retaining more vitamins and nutrients, pressure cooking can be done using less gas or electricity than cooking with conventional methods. Pressure cookers are also a valuable tool for people that live at high altitude because at high altitude the boiling point of water is reduced and water boils at cooler temperatures, meaning that it takes longer for foods to cook. This can be corrected with a pressure cooker.
I hope we have answered any questions you might have about how a pressure cooker works. If reducing cooking time and cooking healthy, delicious meals is important to you, you may want to consider investing in a pressure cooker.