Boiling Water for Better Drinking, Done Right
by Jeremy Elton Jacquot, Los Angeles on 07.17.07
So let's imagine you're stranded on an island, in a forest or any other isolated natural locale of your choice: one of your top priorities will undoubtedly be ensuring you have a proper supply of safe drinking water. But, assuming you've lost your way (or crashed, etc) and now find yourself in said natural locale, you're only likely to have access to sea water or water from a stream or river. What are you to do?
Well, if you happen to have this nifty survival guide lying around, you'll know that boiling water is the most effective way of getting rid of any nasty pathogens that might render your drinking experience, shall we say, "unpleasant." In fact, boiling water is a much better way of obtaining safe drinking water, even when compared to modern marvels like filtering devices or chemical treatments.
Once you get your hands on a container to hold the water and, of course, a source of heat to boil it, you're ready to go. Or are you? The next important matter to consider is the appropriate water boiling time. Various numbers are often thrown around: 10 minutes, 5 minutes, 20 minutes or even 1 minute (which doesn't really work in principle), but there appears to be little consensus as to which is best.
According to the guide's author, however, each above quoted time is wrong. The right amount? Zero minutes. As he explains, heating the water to a temperature of approximately 165°F (74°C) and leaving it for half an hour should be enough to kill any pathogens that are present. You can also raise the temperature up to 185°F if you're in a hurry and leave the water for a few minutes, which should also be enough to destroy any pathogens. No need to up the temperature once you reach the boiling point at 100°C, at which point the pathogens should be gone.
The benefits are clear: you save fuel by not having to consume as much firewood (or whatever biomass source you may choose to use) and don't waste any precious water by letting part of it evaporate. Handy advice to have if you're ever in a tight spot (and want to remain sustainable).
UPDATE: Yes, as several clever readers have already pointed out, you'd need a third device in your toolkit (which we omitted) to make this advice applicable: namely a thermometer. Good luck getting stranded with all three, though.
Also, another reader has just posted a comment noting the information is, as she puts it, "dead wrong," and she recommends checking out the following website. After conducting our own bit of research, we did find out that bleach can be used to eliminate most pathogens in water (if boiling isn't practical), but that it should only be used if boiling water is not practical at all. The main point the guide's author was getting to is that you don't need to boil the water for very long: once you actually reach the boiling point, you should be able to let it cool and safely drink it.
Via ::Survival Topics: How Long Do You Need To Boil Water? (how-to guide)
See also: ::All-Purpose Water Filters For Humanitarian Projects, ::What's in the Water? Ask the National Tap Water Quality Database, ::How to Green Your Water
Of course, if you are in the woods, more than likely you have no way to measure temperature.... except for letting the water boil.... which is a good visual indicator of the current temperature...
I guess if you're stranded with a thermometer, that's great advice.
You folks might need to do a little more research on this issue. The artiel you cite is dead wrong (and I do mean dead, cause this information could kill you!)
a) different pathogens die at different temperatures. While heating the water may kill some bacteria or protozoa, it will not kill all. In addition, there may still be viruses like cholera kicking around in local waterways, waiting to invade your blood stream. Remember, a huge number of folks died at the turn of the century in US and English cities and, more recently, in Peru, from cholera tainted drinking water.
b) boiling sea water will only concentrate the salt, making the water even more hazardous to your health.
c) in fact, boiling water that contains heavy metals will concentrate the metals. So, watch out for arsenic, lead, mercury or whatever else may be in the water. If the water is polluted by oils or oily pollutants, all the worse. Avoid water that looks polluted, it probably is.
Sad to say, but many times the information one finds on the www is simply not accurate or even downright false. Please do not spread this piece, I'd suggest you take it down off your blog.
A better article on this subject is at http://beprepared.com/article.asp?ai=30 and it talks about filtration and solar stills, too!
What? Did you actually READ the complete article you link to? You seem to have missed the final conclusion:
"The correct amount of time to boil water is 0 minutes. Thats right, zero minutes.
The fact is, with a water temperature of 165 degrees F (74 C) it takes just half an hour for all disease causing organisms to be inactivated. At 185 degrees this is cut to just a few minutes. By the time water hits its boiling point of 212 F (100 C) the water is safe. Even at high altitudes the time it takes for the water to reach a rolling boil and then cool means you can safely drink it.
You only need to get your water to a rolling boil. By that point the disease organisms in your water were destroyed quite some time earlier. End of story, turn off the heat. Stop wasting fuel. Let the water cool down. Your water is safe to drink!"
But if you're attempting to remove the salt from that seawater, ahem... which I'd recommend, you're still going to have to boil it.
"b) boiling sea water will only concentrate the salt, making the water even more hazardous to your health."
What Elle means is that you remove salt from saltwater by boiling the water and collecting it's steam as condensation. Yes, any water in the pot will still have salt in it, and at higher concentrations than you started.
Thank you, Ecobra, that is what I was trying to convey.
In short, heating water to sub-boiling temperatures is NOT a means to make unpotable water, potable and even boiling water will not be sufficient in most circumstances.
I do hope they take the original article off Treehugger. It is patently false and anyone who follows its suggestions could sicken and die from fallowing bad information.
Actually, Cholera is caused by the bacteria, Vibrio cholerae. But having said that, I completely agree with Elle--this post should be taken down.
The chance that someone would be in a situation to use this advice and remember it from Treehugger is about the same as Bush buying a Prius, but why risk being responsible for someone getting sick or dying because you posted a bad link?
Correct me if I'm wrong, but this post is not only completely false, but also very dangerous advice to follow. Please, use caution when following advice (OR GIVING IT) off of random sources on the web!
Places where it's absolutely imperative that things are sterile--hospitals, biology labs--use an autoclave. These use high pressure steam to get instruments well past the boiling point of water. Why? Because many microorganisms have no problem at all surviving at temperatures past 100˚C.
Some bacteria form spores in harsh environments--spores survive high temperatures, desiccation, detergents, UV light, etc. Cooking rice contaminated with Bacillus cereus for example, can turn the bacteria into endospores. If left warming in the rice cooker for too long, the bacteria revert back into its reproducible form, which can cause food poisoning.
If you're not convinced, a good place to start would be Wikipedia's entries on sterilization, bacteria (note the part about spores), and autoclaving.
point being if your ever in a situation that you dont have water, yet have ability to boil / find water... you should just die of thirst because of the risk of maybe possibly getting sick...
uh point is survival people... get a clue
I read the following articles before I found this site... they talk about how to filter and purify water when you're in the wilderness
"You need to know how to make a water filter if you face the fact that the only water you can find is dirty muddy water. When you filter water you remove all "visual" particles from the water.
There are a number of different ways to filter dirty water. One simple way to make your own water filter is to use sand and gravel."
http://www.wilderness-survival-skills.com/how-to-make-a-water-filter.html
"In the wild water is seldom pure, so you need to have knowledge about different methods of water purification.
Clean water is essential for survival. Water purification always has to be done if you aren't sure the drinking water is safe. Polluted water can contain harmful microorganisms that transmit diseases and can lead to serious stomach upsets, dehydration and other illness....and could really put you in a wilderness survival situation. "
http://www.wilderness-survival-skills.com/methods-of-water-purification.html
Water once boiled will remain pure for how long?
we can use it for 3 days/4days/6days or more?