[Stratovarius]

I found this nice read here.

$this->bbcode_second_pass_quote('', 'T')he correct amount of time to boil water is 0 minutes. Thats right, zero minutes.

"According to the Wilderness Medical Society, water temperatures above 160° F (70° C) kill all pathogens within 30 minutes and above 185° F (85° C) within a few minutes. So in the time it takes for the water to reach the boiling point (212° F or 100° C) from 160° F (70° C), all pathogens will be killed, even at high altitude."

[steam_cannon]

Great find! And it makes sense too, solar water pasteurization is effective well below a roiling boil...

[SILENTTODD]

Thank you Stratovarius for posting this thread! Drinkable water after air is the most important resource readers of these pages may face in the future. You can survive a 2 to 3 weeks without food. You can only survive a few days without Potable (drinkable) water.

You are absolutely correct that water does not have to be raised to boiling temperature to remove dangerous pathogens. A temperature of 149 F/65 C is all it takes to kill pathogens in drinking water. Read more on this site.

Water Pasteurization

Here is a site you can get a WAPI:

Water Pasteurization Indicator (WAPI)

[gg3]

Excellent find, Strato. Truly excellent and will no doubt save some lives around here.

Generalization: If you don't have a thermometer for measuring water temperature, just get the water to the boiling point and then immediately turn off the heat and let it cool.

However there may still be a bug in the works:

Question: Aren't there some nasty little waterborne bacteria (cryptosporidia?) that form spores or encapsulate themselves in order to survive extreme conditions?, and what measures are needed to deal with those?

[jeezlouise]

CDC says boiling takes care of cryptosporidia too:

CDC website

The tough outer shell allows the germ to survive outside the human body for a while, but boiling gets 'em.

[TheDude]

$this->bbcode_second_pass_quote('SILENTTODD', '[')url=http://www.solarcooking.org/pasteurization/default.htm]Water Pasteurization[/url]

[Stratovarius]

Note that the water remains at a high temperature for a fairly long time after cutting off the heat source since it doesn't drop from 212 F to 100 F in 2 seconds. Thanks to high specific heat capacity and hydrogen bonding, your water will continue to be de-germized while it cools down.

[Chaparral]

There are some bacteria that form endospores that can survive autoclaving. Bacillus subtilis I believe is one but it's not pathogenic. If you just grab a container of water out of an irrigation ditch and commence heating within minutes, those bacteria that can form endospores may not have a chance to do so. If you get water from a puddle that's been drying up in the sun for a few days, its likely that more bacteria will have formed endospores since they do it for the same reason that peakniks prepare: impending hard times. Whether or not such endospore formers are also pathogenic species would be anyone's guess.

[basil_hayden]

I think the point of boiling water has been missed in this thread.

Water that is boiling is 212 degrees or so, you can tell that because it's boiling, without a thermometer.

Sure, 150 degrees might kill almost everything, but if you didn't have a thermometer, how would you know thw water was 150 degrees and not 110 degrees.....

So boiled water is not a myth, but having a thermometer when you need one might be.

[Stratovarius]

You don't have to get the water to 160.000000 F or whatever lol. The point is, occasionally some huge water main breaks in the city and the news-person is telling you to boil your water for 15 minutes which is an arbitrary time.

You just can get it to bubbling then cut off the heat source. You don't need a dang thermometer.

[steam_cannon]

$this->bbcode_second_pass_quote('basil_hayden', 'I') think the point of boiling water has been missed in this thread.

Water that is boiling is 212 degrees or so, you can tell that because it's boiling, without a thermometer.

Sure, 150 degrees might kill almost everything, but if you didn't have a thermometer, how would you know thw water was 150 degrees and not 110 degrees.....

So boiled water is not a myth, but having a thermometer when you need one might be.

[Kingcoal]

The problem here is that we are assuming that you are dealing with fresh water. What about water contaminated with chemical toxins? Also, some bacteria produce toxins that remain after they are dead. In some cases, you might have to distil your water to be absolutely certain it is potable. In a survival situation, a method to collect rain water might be a very good idea. Rain water might contain traces of chemicals from pollution, but not enough to produce harm to humans.

[steam_cannon]

$this->bbcode_second_pass_quote('Kingcoal', 'T')he problem here is that we are assuming that you are dealing with fresh water. What about water contaminated with chemical toxins? Also, some bacteria produce toxins that remain after they are dead.

[Pops]

Actually the EPA says to boil for one minute. Which makes sense in that you might see a few little bubbles coming from the bottom of the container and think you are done but haven’t completely heated the whole thing.

If you've ever had the Sierra Squirts 3 days from the trailhead you would understand that few extra minutes over the fire is well worth the effort.



BTW, thanks for posting those links s_c!

[PrairieMule]

I boil all water 5 min because those that believe 1 min or less is fine are unable to bring a roll of toilet paper or Pepto to my campsite.

I filter everything, period. Even if its clear mountain spring water. Ill use a coffee filter, and even then I'll go back and hit it with a UV Steripen.

Most of the backpacking trails in North Texas revolve around giant lakes full of "Lake Lice"(Jetskis and bassboats). They tend to give lake water a oily taste. Boiling does not remove engine oil.

[Pops]

Just to add another wrinkle: boiled water is only good for immediate use.

Otherwise why pressure-cook some foods in canning to reach a temp higher than 212*?

The answer being, stuff grows from spores in an anaerobic medium given time and some little food if not heated above boiling.

Like Botulism.

[davep]

$this->bbcode_second_pass_quote('Pops', 'J')ust to add another wrinkle: boiled water is only good for immediate use.

Otherwise why pressure-cook some foods in canning to reach a temp higher than 212*?

The answer being, stuff grows from spores in an anaerobic medium given time and some little food if not heated above boiling.

Like Botulism.

[Ludi]

To my knowledge, the organisms which produce botulism do not grow in plain water, so once boiled, and kept in a clean container, water is safe. Water decanted into a dirty container can breed pathogens, however.

[davep]

$this->bbcode_second_pass_quote('Ludi', 'T')o my knowledge, the organisms which produce botulism do not grow in plain water, so once boiled, and kept in a clean container, water is safe. Water decanted into a dirty container can breed pathogens, however.

[PeakOiler]

Here is a pic of the SolAqua water distiller taken earlier this summer:


The still does not boil the rainwater, but it evaporates and recondenses on the underside of the tilted glass, leaving most organic and inorganic impurities behind in the basin.

Flushing a batch still is important, especially if the feedwater is hard, like seawater, or many well-water sources. The still overflow is collected and given to plants (except if the feed water is salty-that's why rainwater is the best!--no salts...) The distilled rainwater goes in the frig or freezer.