The siren song of the mountains calls loud and also clear to many backpackers, which means we’re regularly camping well over sea level. Besides impacting our own physiology, altitude has actually an influence on how long it takes to cook water—and, therefore, just how long it takes to prepare uncooked food. For plenty of of you, the complying with will it is in a no-brainer rehash, but a goodly number of people still acquire (understandably) confused around the relationship in between boiling point, cooking time, and altitude, for this reason we thought we’d run through a quick and basic primer top top the subject. Whether you"re walking ski-touring in the near future or you"re security this winter scheming increase awesome high traverses because that the summer, review on for a small boiling-water-at-altitude 101!

The Basics of cook Water in ~ High Altitudes

At increasing altitude, atmospheric pressure declines. Very roughly speaking, you deserve to think that it prefer this: There’s much more air above a suggest at sea level, which means the atmospheric pressure is higher here than at higher altitudes wherein there’s much less air bearing down above. This fundamental physical rule explains a lot of important weather phenomena as well as that stroked nerves ear-popping thing when you’re paris in an plane or driving up or down a mountainside.

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It additionally impacts the boiling suggest of water: the temperature at which liquid water begins turning to vapor, i m sorry occurs once its vapor pressure equates to the atmospheric pressure. At a greater elevation, the lower atmospheric pressure means heated water get its boiling point much more quickly—i.e., in ~ a lower temperature. Water in ~ sea level boils at 212 degrees Fahrenheit; at 5,000 feet above sea level, the boiling suggest is 203 degrees F. Up in ~ 10,000 feet, water boils at 194 degrees F.

This is the contrary of what many civilization suppose: that water takes longer to cook on high. As we’ve just demonstrated, boiling water in ~ altitude is quicker. But the fact that the cook temperature is lower at greater elevations way food takes longer to cook, i m sorry is whereby the confusion lies. At 5,000 feet, whereby water boils nearly 10 degrees cooler than at sea level, you should roughly double the cooking time.

In regards to a unstable boiling allude elevation equation, subtract around one degree from the cook temperature with each 500-foot boost in elevation.

photo Kristian Keenen

The Wind aspect & other Caveats

Now, keep in mind that high-elevation cooking sites often complete with wind, and that, that course, can affect how lengthy water involves a boil by whipping that gas fire around and also otherwise making the harder to warmth up your pot. Picking a sheltered spot and also shielding your stove and also cook vessel from the gusts with a windscreen will help ward versus this factor, i beg your pardon may also explain why some outdoorspeople think it takes much longer to heat water come a boil up in the mountains.

And climate there"s the reality that different stove fuels perform far better or worse at high elevations and in the colder temperatures commonly encountered increase there. All things considered, liquid-fuel stoves are the finest bet because that high-elevation camping. At high altitude or subfreezing weather, canister stoves won"t work-related as well, and also at ideal it may take much longer to bring your water come a boil, if it gets there at all. (Learn much more in our "Choosing a Backpacking Stove" blogpost.)

The advantages of Mountain residence in the High Country

That longer food preparation time at higher elevations has critical impact ~ above backpacking. To cook the same meal up in the mountains or plateaus, you’ll need to invest much more fuel and much more time. On expanded trips in the high country, foods items that require lengthy and/or multi-step food preparation aren’t good choices, due to the fact that they’ll analyze to hauling the much more fuel in her pack.

Instant-type meals that just require heating are the far better choice, and also that has our just-add-hot-water Mountain home delicacies. In fact, you don’t also need warm water to prepare mountain House: You deserve to use cold water to rehydrate ours freeze-dried meals—just give the food about double the food preparation time provided on the package.

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photo Uncage the soul Productions

Boiling Point, Altitude, and also Water Purification

Now, what around using boiling come purify water—how is that influenced by altitude? cook is the surefire method to kill pathogens and make water for sure to drink. Carry out you need to worry about the reduced boiling temperature that water in the high country?

Basically, you don’t. The Centers for an illness Control & avoidance recommends letting water stand at a rolling boil for a minute in ~ sea level to purify it, and also extending that to 3 minutes of rolling boil above about 6,500 feet. Many experts, however, compete that simply enabling water to with a roll boil renders it safe, nevertheless of her elevation—see this people Health organization document, because that example, and these short articles from turn off the Grid and Backpacker. Also the lower boiling-point temperatures at high mountains on earth is sufficient to death pathogens. If you desire to covering all her bases, by every means, follow the CDC guidelines, however if you’re being fuel-conscious you’re likely going to it is in fine simply bringing water to a rojo boil.

For much more information, check out our Mountain residence blog post on "How come Purify Water" and also definitely our "Tips for cooking at High Altitude."