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At my home and relative's homes I've never seen anyone using a pressure cooker to boil water (to make it safe for drinking). They just take an ordinary steel vessel, fill it with tap water, add some salt and jeera seeds, cover the vessel top partially with a lid and let the water reach boiling point.

I just realized that it might be far more efficient to boil water in a pressure cooker until the first whistle sounds, since it's a closed environment that would lose less energy to the environment. It may boil the water faster (less cooking gas consumption), boil it to a higher temperature (greater variety of bacteria dead) and perhaps lose less water to evaporation. Is this practical or are there downsides to this technique because of which people dont use it?

Elmy
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Julia
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    They add salt to drinking water? – GdD Mar 19 '19 at 08:49
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    Very little salt is added. Just to increase the boiling point. – Julia Mar 20 '19 at 05:40
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    That doesn't actually work @Anon, the amount you'd have to add is huge. See this question: https://cooking.stackexchange.com/questions/6641/does-adding-salt-help-water-boil-faster/6645#6645 . Don't waste your salt. – GdD Mar 20 '19 at 08:08
  • When we get a "boil water advisory" they generally tell you to hold it at a rolling boil for some amount of time ... generally you have to hold it at a higher temperature for less time (eg, it's usually 1 minute at sea-level, but 3 minutes in the mountains) ... so if you're in the mountains and the pressure cooker takes less than 2 minutes more, it's a benefit. (time is your easiest estimate for gas usage, assuming you have the burner on high the whole time ... which it's possible you might turn it down some once it boils) – Joe Mar 24 '19 at 16:06

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Overall it will make little if any difference.

The pressure cooker won't reach 100&degC; noticeably quicker than a normal pan with a close fitting lid, and the pressure cooker is made of thicker metal which will take more energy to heat. Simply closing the lid would help quite a bit.

If you want to hold it at a boil the sealed lid of a pressure cooker would help, except you can't really monitor the temperature. Waiting until it whistles will mean it has been boiling for long enough to produce enough pressure for a whistle, but that's still a measure of pressure, not time.

There are a few species killed by the temperatures achieved in a pressure cooker, and not at 100&degC; but my understanding is that these aren't the pathogens that tend to contaminate drinking water.

As you're flavouring the water as well, you may have to adapt the quantities of seeds if you use a pressure cooker, because the flavour will extract faster.

Chris H
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    This is not entirely true - pressure cookers in the US tend to function at 15 psi - which raises the boiling point to 121 C (250 F), which is the same temperature and pressure used in autoclaves in laboratories and is considered sterilizing. Some also have a lower pressure setting which is does not reach sterilizing conditions. – bob1 Mar 20 '19 at 13:57
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    Unless the OP lives on, say, the Tibetan Plateau, where water in an unpressurised container boils at 85C... but even that is enough to kill _active_ pathogens. – Robin Betts Mar 23 '19 at 07:39
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never ever boil water in a pressure cooker, because, that may result in serious burn injuries... especially your facial area...

manuja
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