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soumodeler
02-03-2015, 22:26
I was out hiking yesterday around Three Forks in about 25* weather and didn't really consider my Sawyer Mini in the lid of my pack. I was out for about 4.5 hours, and there was ice forming in my water bottles. Is this one useless now? It has not been used in a couple of months, so it was not full of water, but I am sure some was left in it.

I always sleep with it in my sleeping bag, but had never hiked in sub freezing conditions until yesterday, so I wasn't really thinking about it.

Starchild
02-03-2015, 22:37
From a former WB discussion the conclusion is the filter can no longer be trusted to be sae, and there is no test that is available to test it if it freezes.

Other filters cold be tested by filtering food colored water and if the color gets thru then it's no good, but this does not work for Sawyer.

Coffee
02-03-2015, 22:57
I have a trip coming up and I am probably going to take aquamira rather than my Sawyer for this reason. I don't want to start wondering if I was able to keep it from freezing.

saltysack
02-03-2015, 22:59
Had same thing happen....fortunately the mini had just come out days earlier....had excuse to buy...I now keep it in my pants pocket while hiking and at night in the bottom of my sleeping bag with breakfast cliff bar, fuel canister....


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pickNgrin
02-04-2015, 10:04
The Sawyer filter uses hollow fiber membrane which was developed for use in kidney dialysis. It is rated as "absolute", meaning that no pore in the entire membrane exceeds the stated filtration size (0.1 micron).

It is impossible to get all of the water out of the membrane once it has been used. If that water freezes, it can rupture some of the hollow fibers (water expands when it freezes). Then you no longer have an absolute filter. You have a possible way for large particles (e.g. giardia and cryptosporidium) to get through.

Since you witnessed water freezing in your water bottle, I would consider the filter compromised. As said before, there is no easy way to determine if the membranes have been ruptured.

squeezebox
02-04-2015, 23:43
So what's the best, easiest way to protect a sawyer from freezing? A pant's pocket just does not seem like enough insulation, the facing out side just might freeze, and there's no telling if it did. I'm thinking of tying it to a string or ribbon around my neck on top of my t shirt and under my base layer should work. Once it gets past freeze warnings I'll probably replace it, they are cheap. Your opinion?

Starchild
02-05-2015, 10:01
So what's the best, easiest way to protect a sawyer from freezing? A pant's pocket just does not seem like enough insulation, the facing out side just might freeze, and there's no telling if it did. I'm thinking of tying it to a string or ribbon around my neck on top of my t shirt and under my base layer should work. Once it gets past freeze warnings I'll probably replace it, they are cheap. Your opinion?


When I used to carry a camelback I sometimes froze the hose, usually by the valve. Placing just the end part inside my jacket almost always got it flowing again (when it didn't it was due to the rest of the tube freezing). So inside your jacket should be fine.

Steripen, well the Freedom model is also temp sensitive and I kept it in my front pants pocket and that worked great in the cold.

Chemical methods also don't work the best in the cold either, requiring a longer time to do their thing.

OTOH the ice cold water is not conducive to microbe growth so your risk is lower as well.

RangerZ
02-05-2015, 12:39
When I used to carry a camelback I sometimes froze the hose, usually by the valve. Placing just the end part inside my jacket almost always got it flowing again (when it didn't it was due to the rest of the tube freezing). So inside your jacket should be fine.

Steripen, well the Freedom model is also temp sensitive and I kept it in my front pants pocket and that worked great in the cold.

Chemical methods also don't work the best in the cold either, requiring a longer time to do their thing.

OTOH the ice cold water is not conducive to microbe growth so your risk is lower as well.


One way to reduce the chance of the drinking tube from freezing is to blow the water back out of it and into the bladder.

ny breakfast
02-05-2015, 20:54
i had mine freeze up i continued to use it for pre filtering with aquamira till i replaced it

CarlZ993
02-05-2015, 23:20
If it is cold enough to wear a jacket, I'd assume carrying the Sawyer in your shirt pocket underneath the jacket would be sufficient to keep it from freezing. Pants pocket? I don't know if there is enough body heat to ensure its effectiveness.

I recall reading that Aquamira drops will freeze somewhere around 15 deg. If you go south of that for any length of time, you may need tablets or another method.

Note: I used Aquamira drops my entire AT hike. The lowest temp I encountered was somewhere around 15 deg. I had purified my water the previous evening before it got that cold. I didn't have any problems w/ my water purification system the entire hike (sometimes the water looked a little murky).

saltysack
02-06-2015, 08:55
If it is cold enough to wear a jacket, I'd assume carrying the Sawyer in your shirt pocket underneath the jacket would be sufficient to keep it from freezing. Pants pocket? I don't know if there is enough body heat to ensure its effectiveness.

I recall reading that Aquamira drops will freeze somewhere around 15 deg. If you go south of that for any length of time, you may need tablets or another method.

Note: I used Aquamira drops my entire AT hike. The lowest temp I encountered was somewhere around 15 deg. I had purified my water the previous evening before it got that cold. I didn't have any problems w/ my water purification system the entire hike (sometimes the water looked a little murky).

Try putting ur bare hands in ur pocket while hiking...lots of heat generated....agree about jacket but I always just wear my cap 4 hoodie to hike in(no pockets) if under about 40 deg.....I overheat easily so seldom wear jacket hiking....granted 15 deg is about the coldest I've hiked in....have worn OR helium 11 rain/wind shell at 15 but no pockets....at night in bottom of sleeping bag....only bad thing about sawyer...don't know if it's ever froze.....


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barich942
02-10-2015, 23:00
I had this concern also. I bring a second method for back up.

The Solemates
02-11-2015, 12:01
so why do normal filters (say the popular 'Hiker' model) not have this freezing issue? Is it because they have glass fibers that will not expand and bust when frozen?

CarlZ993
02-11-2015, 14:31
Try putting ur bare hands in ur pocket while hiking...lots of heat generated....agree about jacket but I always just wear my cap 4 hoodie to hike in(no pockets) if under about 40 deg.....I overheat easily so seldom wear jacket hiking....granted 15 deg is about the coldest I've hiked in....have worn OR helium 11 rain/wind shell at 15 but no pockets....at night in bottom of sleeping bag....only bad thing about sawyer...don't know if it's ever froze.....


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You are probably right the front pants pockets. I was thinking about the side pockets in my hiking pants. That's where I'd put mine. Need a scientist-type do a field test on each premise. :)