I found this quote:

"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."

on this page of survival topics:

http://www.survivaltopics.com/survival/how-long-do-you-need-to-boil-water/

Problem is you may not have a thermometer with you, hence, bringing the water to a boil to be absolutely certain. Sorry to digress, now back to your regularly scheduled topic.

They are incorrect in part-water at high altitude and low
barometric pressure water will be boiling at lower temperature.
It will likely kill living pathogens as they say.

IIRC, the boiling point at 29,000 feet (summit Mt Everest) is 170F. You will be able to kill the bad guys in your water. At really high altitudes, water contamination should not be problem, except in exceptional situations.

Just don't eat yellow snow.

Although not common water borne pathogens, 160/185 degrees F will not kill spore forming bacteria (Cloistral and Bacilli), nor heat stable exo- and endo-toxins.

Pete

I did prelim testing on the stoves I plan on trying out this weekend, in sub freezing weather. I put it in my blog in my sig, but here it is if you dont feel like linking:

Good afternoon, its been a while since I updated this blog. Without going into detail, suffice it to say that life just sometimes gets crazy, and you cannot always accomplish everything you want to do, so you make sacrifices where you can. This was one of them. But, I want to put something in here, and TRY to post monthly. I had asked a question on the ETS forums regarding the use of alcohol stoves in below freezing weather. Well, I decided to take it upon myself instead, and do a practical test. This is by NO means a definitive one-this is simply something that I wanted to try & test out to gather some general data. I am using the following equipment for my test:
a GSI 1L cookset-filled consistently with 16 oz of water (measured from my nalgene bottle)
A Snowpeak Gigapower piezo stove, with a small gas canister (full for this test)
A homemade cat stove
A Mini-Trangia brass stove
A Minibull Designs mini Atomic stove
A Pepsi Stove

The first of the two tests I am doing is the control test. What I did was simply boil 16 oz of water on each stove, and timed the stoves until it reached a rolling boil. Note; yours may vary. The fuel I used was standard denatured alcohol, that was about a year old. I also picked some up for this test, as I only had enough left to test indoors. Which means that the outdoor test will be done with relatively fresh fuel (canister stove being the exception.). I measured out the 16 oz of water, for each test, using a standard nalgene bottle, filling it up to the hash mark. I used tap water, cold, for each test. Additionally, I cooled the cookpot in between each test, so as to minimize possibly skewing the results with a warm pot (I simply ran cold water into it each time, until the pot was cold again-nothing fancy). Here are the results of my indoor control test:

Gigapower canister stove-reached rolling boil in 3:56. Of course, thats the advantage of these types of stoves-a rolling boil, fast. This was by FAR the quickest of all boil times. The fuel is isopro, so I am anxious to see what the outside performance will be, as they traditionally dont operate well at low temps.

Homemade cat stove-reached rolling boil in 10:42. I used a heat reflector shield with this as well. The design for the stove is simple-its an empty cat food can, with holes punched in it. You fill it with alcohol to the bottom of the row of holes, light it, and set the pot directly on the top. The boil used ALL the fuel for this-I suspect that, when doing this test outdoors, it may not reach boiling, due to the lower temps. But, right now, that is only a suspicion.

Mini Trangia-reached rolling boil in 10:46. This only consumed roughly 1/3 the fuel in the stove. This is the standard brass Trangia alcohol stove, that has been in use for damn near ever. Honestly, these are my favorite alcohol stoves, due to their heavy duty build. And, you can keep alcohol within the stove itself, with its lid. This also came with a simmer lid, which I find completely useless, as I am of the mind that cooking, while hiking, consists of boiling water & adding it to the dehydrated food. But, again, this is personal preference. Your experiences may differ. The simmering gizmo is simply a lid that restricts some of the heat output, by limiting the amount of jets being used.

Pepsi Can Stove-reached a boil in 5:23. This was a LOT faster than I expected! I used a pot stand for the test, as this type of stove isnt a sit-on-top kind. It took about 15 seconds for the jets to ignite. Used about a 3rd of the way up for fuel, which seemed to be maybe just a little too much, by about a minute's worth of burn time.

Minibull Designs mini Atomic-reached boil in 5:34. This was surprising, as I expected it to hit boil before the pepsi can stove did. The first time I tried, I didnt add enoug fuel-its hard to judge how much you put in it without graded measuring lines on your fuel dispenser. So, the second time, I filled it with more than I thought I would need, which worked (I cooled the pot off in between too-in fact, I ate dinner between the first & second tries).


My control experiments left me with a few thoughts-first, canister stoves are quick & easy. But, that is expected. The downside is that you need to pack out empty fuel canisters, which are still heavy (comparitively speaking). Also, if they break, you are pretty much SOL, if it cannot be fixed immediately.
Alcohol stoves can be lightweight, and with the correct design, are within acceptable boiling times-comparable to my canister stove-at least inside. We will see what changes, if any, to boil times outside, in the cold. The great thing about alcohol stoves is that they are simple-pour fuel in, light, and go. No moving parts, nothing to clog. Fuel I keep in an empty soda bottle. They are delicate though (with the exception of the Trangia), and can be easily crushed if stepped on. Of course, if you can find another one, and have something small to poke the jets through with, you can make another one. The design is insanely simple. From everything I have read, the downside is that these will not work in sub-freezing weather. I have no first hand experience with that-which is what I will be testing this coming weekend!

Look for another post shortly after the coming weekend with post-outdoor test information.