Pressure cookers.

Slow cookers.

Rice cookers.

Whatever this is.

Are all these gizmos taking up space on your countertop actually bringing anything to the table?

Or are they just so many glorified pots?

The answer depends on how you want to use them.

And a bit of cooking chemistry.

These are all "wet" cooking methods -- they rely on water to transfer heat into your food, and that results in the chemical and physical changes that make raw meat palatable and dry grains tender.

First up: the pressure cooker.

If you want dry beans ready in a flash, this is for you.

You might actually have noticed that water boils at a lower temperature when the pressure is low, like up high in the Rocky Mountains.

And the opposite is true as well.

Ramp up the pressure, and the boiling point of water goes up too.

Depending on the model of your pressure cooker, it can boost the pressure on your food by 11 to 15 pounds per square inch.

And that will increase the boiling point of water from 100 degrees Celsius to 120.

Hotter water will cook food faster.

There's more energy, in the form of heat, to drive the chemistry that leads to doneness in meat -- stuff like dissolving tough collagen into gelatin, making it tender.

And the pressure also drives water into your beans and rice, so those get done faster too.

The increasingly popular sous vide style of cooking is almost the polar opposite of a pressure cooker.

If pressure cookers are for cooking things fast and hot, sous vide is for cooking them low and slow.

That's because you can control the exact temperature your food will come to without ever overshooting.

And it's once again thanks to water.

See, it's possible to calculate the exact temperature that will result in food being done, but not overdone.

We know the temperature it takes to dissolve collagen and disrupt other proteins to cook meat.

And we know the temperatures that are required to kill harmful bacteria for food safety.

But with normal cooking methods, we tend to overshoot those temperatures badly.

That's because for a piece of meat to reach the doneness temperature in the middle, you need a hot pan at a much higher temperature to get enough heat to diffuse into the center.

Those high temperatures, if you're not careful, can result in burning, or dryness, or other not so great stuff.

But with sous vide, you vacuum seal your food and sink it into a water bath set to the exact temperature you want.

Water conducts heat into the food more efficiently than air, hence the vacuum sealing.

And over time, the food comes to equilibrium with the temperature of the water bath.

The perfect doneness temperature, and not a degree more.

Slow cookers are a little bit like sous vide lite.

You're still heating to a relatively low temperature, letting time do the work of carrying cooking reactions along far enough that your food is both fully cooked and safe to eat.

But you're not immersing the food in a perfectly controlled water bath.

Instead, there's a fairly ordinary heating element in there delivering relatively low heat to your food.

It's possible to overshoot, and therefore overcook.

But it'll take a while -- like, no need to panic if you let it go an hour longer than you meant to.

If you ask me, the real benefit to an electric slow cooker is being able to leave something to cook for a long time without worrying about leaving the gas on.