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Heading to Mars tomorrow, and I want to make sure I can still make my famous bean soup. Ordinarily I just cook it in a pot, but I remembered that beans are hard to cook at high altitudes, and Mars is like really high up, so I guess I need a pressure cooker. I'm at a department store now, and all the nice adjustable-pressure pressure cookers are out of stock, but there's a remarkably wide range of cheap fixed-pressure pressure cookers. What pressure rating should I choose, so that the effect is likely the same as cooking at sea level on Earth?

NOTE: I'll be cooking my beans outside.

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You want

a pressure equal to that of the earth's atmosphere.

But (I think) the way a simple pressure cooker works is by

having a weight which needs to counterbalance the force exerted by vapour trying to escape --

so because

Mars's gravity is only about 0.38x that of earth, you'll need a proportionally heavier weight.

So you'll want a pressure cooker rated for

1/0.38 of normal Earth atmospheric pressure, or about 2.6 bar. (Plus the atmospheric pressure of Mars's atmosphere, but that's something like 1% that of earth so we can ignore it.)

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  • $\begingroup$ Well done! [Like the beans!] $\endgroup$ – Sneftel Nov 24 '17 at 15:15
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I'm not sure if this is how fixed-pressure cookers work, but:

1 bar

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  • $\begingroup$ mm, not quite... the pressure ratings given are the difference between the ambient pressure and the internal pressure. $\endgroup$ – Sneftel Nov 24 '17 at 14:26
  • $\begingroup$ Ah, I see, changed it then. $\endgroup$ – mr23ceec Nov 24 '17 at 14:38
  • $\begingroup$ Still not right, though that's the logical answer. $\endgroup$ – Sneftel Nov 24 '17 at 14:39

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