xkcd #3187: High Altitude Cooking Instructions
Title text:
1,300,000-1,400,000 ft: Ask a crew member to show you how to use the ISS food warmer.
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Source: https://xkcd.com/3187/
this post was submitted on 29 Dec 2025
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If you're cooking something at altitude you shouldn't lower the heat - you still need to cook it properly.
Boiling water is a fixed temperature at a given air pressure. Turning up the heat doesn't make the water hotter. You just lose it faster. If you need higher temperatures and are cooking in boiling water, then you have to use a pressure cooker.
Who said anything about turning the heat UP?
I meant up relative to the boiling point. Since the boiling point is lower, the same heat output is relatively higher. It just boils the water faster and does nothing to the temperature. You just need enough heat to get it to a boil if you don't want to waste extra water and heat.
The pressure difference doesn't change how many joules of energy needs to enter the food to cook it.
But it does change how much power you need to use. If you leave the power the same, you'll need more joules because you need more time and are sending more of it to the atmosphere.