Cold Weather Test for Water Bottles

Cold Weather Test for Water Bottles

Page Type Page Type: Article

Cold Weather Test for Water Bottles

Staying hydrated in the winter is very important. It is hard to drink frozen water! Here is a simple test of waterbottle done to simulate typical conditions in Colorado.

Cold Weather TestLeft to right: Walmart thermos, Nalgene bottle with OR insulating jacket, REI thermos.

Initial measured water temperature just before placement in the freezer was 69.8F. 850 ml of water was used for all items to prevent cracking of bottle during expansion.


The bottles were placed in the freezer at 8:07 PM October 11 2007. A digital high/low thermometer accurate to 0.1 degrees F was used to record the freezer temperature.

By morning it was found that the freezer temperature stayed between 3.5F and 7.2F throughout the night.


Average winter temperatures on Pike Peak are displayed in the following summary of the weather statistics:

Pikes Peak Weather Statistics

Of course it is often colder than average. Displayed below are some of the temperatures I have camped in the local area for each month of the year:

Overnight Temperatures in the Central (US) Rockies

It is evident that the recorded temperature of the freezer is fairly typical in temperature when compared with the weather statistics on the highest Colorado mountains.

The bottles were all removed from freezer at 7:22 AM on October 12 2007. This is 11 hours 15 minutes after their placement. As per my experience 10-14 hours is a typical time to climb in a day for winter ascents.



Nalgene bottle with OR insulating jacket

Notice that the Nalgene bottle (which was placed upside down in the freezer is frozen. It still did better than expected. Approximately 40% of the water in the bottle was frozen. The remaining portion of unfrozen water was at about 32F. Since I’ve had water freeze completely solid on climbs, it shows how cold those days were on those particular climbs.

Walmart thermos

This did surprisingly well. I have actually had water turn slushy in it on very cold days, but for this test the water stayed well above freezing. The measured temperature at the end of the test was 42.4F, well above the freezing threshold.


REI thermos

This is the best performer. I have never had water freeze while using this product. For this test the measured temperature at the end of the test was 50.2F, well above freezing.



For cold winter climbs, do not rely solely on Nalgene bottles and insulating jackets unless you have them close to your body the entire time. At a minimum, take at least one high quality thermos (such as the REI one) to make sure you have water available after the Nalgene bottle freezes.


Post a Comment
Viewing: 21-33 of 33
Eric Holle

Eric Holle - Oct 21, 2007 7:17 pm - Hasn't voted

Also check out....

the Thermos Nissan line. They are possibly higher quality than the REI thermos, a little pricier, but well worth the cost. They keep heated contents very warm, or cold contents cold for extended periods of time using double wall vacuum insulation technology.


deep6 - Oct 22, 2007 7:56 pm - Hasn't voted

I Wonder How These Would Hold Up to the Freezer Test?

i know these probably shouldn't be put into the freezer but, i was wondering how both of these popular water bottles (*both available at rei) would hold up in freezing temps and what would happen to the contents inside? here's a link to both the klean kanteen water bottles and sigg brand water bottles:

The Ogre

The Ogre - Oct 22, 2007 9:53 pm - Hasn't voted

Great experiment

I agree with others' comments that agitating the bottles would bring a different result.
Personally, I have been carrying three Nalgene bottles with insulating jackets (Granite Gear brand). I just bought an EMS brand jacket that seems nicer (similar to the OR but cheaper). I like to hang one of the bottles on my hip belt (for easy access) and keep two in my pack.
I think that I will try a new strategy: Still use a Nalgene on the belt, but keep one or two Thermoses in the pack (instead of the other Nalgenes). I am going to look into the REI and SIGG models.

Scott, on a related note, I wonder if it would make any difference with #2 plastic Nalgenes instead of #7 plastic. Word on the street is that the "classic" Nalgene (#7 plastic) are not good for you (leaching of chemicals into your drink, etc).


lins - Oct 24, 2007 8:08 am - Hasn't voted

good experiment

i used a pair of thermo bottles very similar than the REI (but from a European brand... maybe made by the same manufacturer) in an extreme race in northern Minnesota in February.
After 12 hours at -30 F average, my water didn't freeze

very good experiment ;)


Sawtooth - Nov 4, 2007 1:41 pm - Hasn't voted


I'd be interested in the comparative weights of the Nalgene/jacket and two thermoses, if you have them. Thanks. Great test and report!


Sawtooth - Nov 4, 2007 2:40 pm - Hasn't voted



Can you tell us what thermometer you used?


Scott - Nov 5, 2007 7:58 pm - Hasn't voted

Re: Thermometer?

An accurite digital hi/low.


TheBootfitter - Nov 9, 2007 2:01 pm - Hasn't voted


Hey! Thanks for posting this! I've done some controlled experiments along these lines as well. My objective has generally been to compare the performance of different types of foam insulators. I have found the Granite Gear Aquatherms to perform consistently better than the OR water bottle parkas. A thermos, of course, is far more efficient, but also a lot heavier. (The thermos in my experiments was also an REI 1-Liter.) See below for links.

[url=]"How to keep water from freezing" thread on a different forum -- with results of my experiment[/url]

[url=]Review of Granite Gear Aquatherms on Backpack Gear Test[/url]


Grampahawk - Nov 15, 2007 6:36 pm - Hasn't voted

heat wrap

In really cold weather I have started with hot water and have also used duct tape to hold a heat wrap around my Nalgene. This also provides a nice way to warm your sleeping bag if you are camping out.


big_g - Nov 17, 2007 2:01 pm - Hasn't voted

I have 2 new thermoses now

Thanks Scott. You influenced me to buy a thermos. I picked up a Mountain Gear branded model that looks very similar in construction to the REI model except with a black powder coat. I love it.

Filled with near boiling water after over 8 hours in the freezer it was still hot to drink. After 22+ hours it was room temp. So happy with it I decided to keep the 2nd one that I accidentally ordered at the same time.


Mountain4ice - Nov 19, 2007 12:55 am - Hasn't voted

Thanksgiving test

I will be doing some real world testing this Thanksgiving on Mt Whitney. Last year I had some frozen bottles this year I hope to keep them flowing. I will post results when we get back.


hikin_jim - Nov 19, 2007 3:58 pm - Hasn't voted

Great Post

Great post! I'm headed up to Canada for a little "fun" in December/January. I've got a 0.5 L thermos, but may need to pick up a bigger 1.0L one.

sgladbach - Feb 4, 2008 3:27 pm - Hasn't voted

I took your advice

At the beggining of this winter, i began carrying thermos on every trip. I love it!
I make a hot tea with lots of sugar and use it for a warm-me up/pick me up. i got a lightweight floating (mostly plastic) 1 quart thermos from Walmart $18. I works great, even in 20 below weather.

Viewing: 21-33 of 33