Thursday/ cooking with pressure is a pleasure

I have had my Instant Pot pressure cooker for a week now, and I’m still learning to use it —but I like it a lot.

So far I have cooked regular oats, steel-cut oats, rice, Brussels sprouts, asparagus and sweet potato in it. Asparagus is ready in an instant with an official cooking time of 0 minutes. You put them in, and they’re done. Howzat! 😂
Let me explain. The laws of physics still apply. Even if you put the water and asparagus in the cooker and tell it to cook for 0 minutes, it will still take 5-10 mins to get to the operating temperature and pressure inside. During that time it already cooks the food inside. Something as delicate as asparagus is then cooked already. Voila.

I put this sweet potato in for 20 minutes and it came out perfectly cooked. (I let the pressure go down by itself for another 10 mins or so). I used to bake these root vegetables in the oven: a 45-minute endeavor with tin foil, and then the sugar sometimes oozes out of the venting holes I made into the skin with a fork, and bake into black, as well.
Water, the versatile substance of life, comes in three phases, depending on its temperature⁠— and the pressure it is under. Liquid water under a higher pressure cooks (turns into steam) at a higher temperature. A pressure cooker operates at roughly 2 atmospheres of pressure —12 to 15 pounds per square inch (psi) above atmospheric pressure (which is roughly 15 psi). At 12 psi above sea level pressure, pressure water boils at 117 °C (243 °F). Yes, that sounds like a modest temperature elevation compared to an oven, but the steam sealed in the cooker has an enormous capacity for carrying and transmitting heat to the food to cook it. 
Just as an interesting aside: the triple point of water occurs at 0.01 °C in a near-vacuum. That point at the upper right called the critical point is where water vapor (steam) is warm enough so that no amount of pressure brought to bear on it, will liquefy it.

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