What do pressure cookers do to food that traditional cooking methods can’t?
In: Chemistry
Heat impacts the rate at which food is cooked at an exponential rate: It roughly doubles every 10°C increase. So if cooking something in a regular pot at 100°C takes 4 hours, it will take just 1 hour in a pressure cooker at 120°C. There might be some other beneficial chemical reactions that only happen at a higher temperature, but I don’t know any specifics about that.
The benefit of a pressure cook is speed not cooking style. Think of a pressure cooker like being a crockpot on ultra fast mode.
A pressure cooker can cook FAR faster than other methods that would use similar ways to prepare the same food. Things that you would have in a crockpot all day to cook can be done in a pressure cooker in 30-60 minutes. Rice can be made in 5.
They don’t do anything another method couldn’t do just as well– they just do it way faster.
Pressure cookers increase the pressure which means that the water can get hotter and cook the food faster.
Water boils at 212 degrees Fahrenheit or 100 degrees Celsius at sea level. If you’re up on a mountaintop there’s less pressure and the water boils at a lower temperature. The reason is because boiling is the water getting enough energy for the water molecules to fly away from the other water. If there’s a lot of pressure around it has to get more energy to get loose if there’s not much pressure around it doesn’t need as much. In space it could just disappear when there’s no pressure.
When you heat up the water inside of a sealed container like a pressure cooker then the pressure keeps getting stronger and stronger and stronger and the water can get hotter and cook the food faster.
They allow the food to be cooked at a higher temperature than is otherwise possible. Food at atmospheric pressure, if it contains water, cannot itself get hotter than 212F/100C (at sea level). It may be exposed to higher temperatures than that, but it can’t be higher because the extra heat energy will go into evaporating the water. A pressure cooker allows the temperatures to go higher because the pressure increases the temperature at which the water will become steam.
Oh…that’s a great idea and makes a lot of sense!
Others explained how it works, but as an example I like to use mine to turn sweetened condensed milk into caramel or dulce de leche. You just put the whole unopened can inside, cover it with water, and let it cook for a few hours. The longer you cook it the thicker and more caramelized it gets. I buy the condensed milk when it goes on sale and I always have caramel to put on desserts or snacks or in coffee. It can’t burn because no part of the milk can can get hotter than the surrounding water and the can can’t explode because of the equal external pressure.
Without a pressure cooker you’d have to be standing over the stove for most of the day constantly stirring it to keep it from burning on the bottom of your pot.
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