The siren song of the mountains calls loud and also clear to most backpackers, which means we’re often camping well over sea level. Besides impacting our very own physiology, altitude has an affect on just how long the takes to cook water—and, therefore, how long it takes come prepare uncooked food. For many of you, the complying with will it is in a no-brainer rehash, but a goodly number of people still acquire (understandably) confused about the relationship between boiling point, cooking time, and altitude, for this reason we believed we’d run through a rapid and simple primer ~ above the subject. Even if it is you\"re walking ski-touring in the near future or you\"re safety this winter scheming increase awesome high traverses because that the summer, check out on because that a little boiling-water-at-altitude 101!
The Basics of cook Water at High Altitudes
At increasing altitude, atmospheric pressure declines. Really roughly speaking, you have the right to think the it favor this: There’s more air above a allude at sea level, which way the atmospheric push is better here 보다 at higher altitudes where there’s much less air bearing down above. This fundamental physical rule explains a lot of of essential weather phenomena as well as that annoying ear-popping thing when you’re paris in an plane or driving increase or down a mountainside.
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It additionally impacts the boiling point of water: the temperature in ~ which liquid water begins turning to vapor, i m sorry occurs as soon as its vapor pressure equates to the atmospheric pressure. At a greater elevation, the lower atmospheric pressure means heated water will its cook point an ext quickly—i.e., at a lower temperature. Water at sea level boils in ~ 212 degrees Fahrenheit; at 5,000 feet above sea level, the boiling suggest is 203 levels F. Up at 10,000 feet, water boils in ~ 194 degrees F.
This is the contrary of what many human being suppose: the water takes much longer to boil on high. Together we’ve just demonstrated, boiling water in ~ altitude is quicker. However the reality that the cook temperature is reduced at greater elevations means food takes much longer to cook, i beg your pardon is whereby the man lies. In ~ 5,000 feet, wherein water boils nearly 10 levels cooler than at sea level, you need to roughly twin the food preparation time.
In terms of a turbulent boiling point elevation equation, subtract around one level from the cook temperature with each 500-foot increase in elevation.
photo Kristian Keenen
The Wind factor & various other Caveats
Now, store in mind that high-elevation cooking sites often complete with wind, and that, the course, can affect how lengthy water concerns a boil by whipping the gas flame around and otherwise making that harder to heat up her pot. Picking a sheltered spot and also shielding her stove and also cook vessel indigenous the gusts with a windscreen will assist ward versus this factor, i beg your pardon may likewise explain why some outdoorspeople think it takes much longer to warmth water come a boil up in the mountains.
And then there\"s the reality that various stove fuel perform far better or worse in ~ high elevations and in the cooler temperatures commonly encountered increase there. All points considered, liquid-fuel stoves room the ideal bet because that high-elevation camping. In ~ high altitude or subfreezing weather, canister stoves won\"t work as well, and also at best it may take much longer to carry your water come a boil, if it it s okay there in ~ all. (Learn more in ours \"Choosing a Backpacking Stove\" blogpost.)
The benefits of Mountain house in the High Country
That longer food preparation time at greater elevations has an important impact top top backpacking. To chef the exact same meal up in the mountains or plateaus, you’ll must invest an ext fuel and more time. On prolonged trips in the high country, foodstuffs that require prolonged and/or multi-step food preparation aren’t an excellent choices, since they’ll interpret to hauling that much more fuel in your pack.
Instant-type meals that merely require heating room the much better choice, and also that has our just-add-hot-water Mountain residence delicacies. In fact, friend don’t even need hot water to prepare mountain House: You deserve to use cold water come rehydrate ours freeze-dried meals—just provide the food about twin the food preparation time detailed on the package.
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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 way to kill pathogens and make water for sure to drink. Execute you should worry about the reduced boiling temperature the water in the high country?
Basically, girlfriend don’t. The Centers for condition Control & avoidance recommends letting water was standing at a rolling cook for a minute in ~ sea level to purify it, and also extending that to three minutes the rolling cook above around 6,500 feet. Many experts, however, complete that simply allowing water to with a rojo boil makes it safe, regardless of your elevation—see this world Health company document, for example, and also these short articles from turn off the Grid and also Backpacker. Also the lower boiling-point temperature at high mountains on planet is sufficient to kill pathogens. If you want to covering all her bases, by all means, monitor the CDC guidelines, yet if you’re being fuel-conscious you’re most likely going to be fine merely bringing water come a roll boil.
For much more information, check out our Mountain residence blog write-up on \"How come Purify Water\" and also definitely ours \"Tips for cooking at High Altitude.\"