I don't do any winter climbing but this was a very interesting home experiment.
Thanks for putting the effort for this interesting experiment. I have tried various thermoses, but REI one has been my favorite. There is nothing like a hot apple cider on a cold winter summit!
Try agitating the water a little - like what would happen while you are walking. This will help the water to freeze, especially if it's very pure (i.e. filtered water) because the water needs some impurities to start growing an ice crystal. With pure water, you might find it well below 32F and not frozen until you shake it! Nice experiment.
science fair project. Really cool and unefull information Scott. Great idea.
is to see the pipe of a camelbak freezing and getting useless, below 0°C.
I agree, my insulated camelbak tube has helped to keep water cool in summer as well as freezing in winter, but it has frozen over many times while I ski. I've found one of the best ways to prevent freezing in the tubes was to blow all the water back into the bladder because the water within the tube was an easier target for freezing. I'd love to see an article comparing the various bladder tube assemblies and the "insulation".
Great read-I'll have to checkout the REI insulated thermos...
...I see an REI purchase in the near future! Sometimes, I've even taken a stove just to melt snowobviously cumbersome and time-consuming! Thanks for making the effort on this, Scott!
...is that as you drink water from said bottle/thermos, the volume decreases and becomes more able to freeze. From pure field observations (not scientifically setup) I have inserted two nalgenes into identical OR sleeves with warm water, one full and the other a bit less than half full. After several hours of skiing around, the bottle with less water has begun to slush-up and freeze, while the full bottle is still warm.
So keep that in mind as water gets drunk from the bottle, the system is changing. On some very cold days I've had the bottom 10oz or so freeze solid and I just have to switch to another bottle.
thanks for your work....can you post the weights of each bottle tested?...or...i guess i can stop being lazy and look them up myself :)
Valuable experiment for all of us that venture out in the cold months...
Thanks for the experiment. It is one more valuable tidbit to take into acount.
Thanks for posting this article Scott.
Thakns for the home experiment. Gearing up for my first winter mountaineering season. Really usefull!
Awesome! I'm excited that the REI thermos performed so well. I'll have to remember that the next time I'm at work.
Way cool, now I can pull my thermos out of storage!!
Also as a note - frozen nalgene bottles can shatter if dropped on large rock from slight distance - but thats about the only time a Nalgene will break
Good stuff here - I also use a thermos as well
Good beta I just had two nalgene bottles freeze solid on me on Mt Langley a couple weeks ago. the REI thermos seems like the way to go
Do you work for REI? What do you reckon the difference between the two thermos is due to?
Do you work for REI?
Nope. Actually I just threw this experiment together to answer a question on the 14ers.com forum. I disagreed that Nalgene jackets are always adequate for winter climbs in this area and since I already wrote it all up, I thought I'd copy my forum post over there as an article over here as well. Here's the thread and my first post if you want to read it:
The same article here is the forum post at the beginning of page 3.
What do you reckon the difference between the two thermos is due to?
The REI one is definately better built. On the other hand, it's also almost 3 times more expensive, so it should be better built. The Walmart thermos is probably more meant for taking hot beverages to work or maybe the ski slopes; the REI for the outdoors. I'm actually surprised the Walmart thermos did so well. I still wouldn't want to drop it too many times, but it is still better than just a Nalgene with a jacket.