Last night I had a brain wave.

I was thinking about winter survival (and winter hiking) and was thinking about the problem of water. Getting water is as simple as finding snow and melting it with a stove or fire...easy. Keeping it in a drinkable liquid form can be tricky. I decided that the next time I go out I would suck up the extra weight and bring a Thermos bottle. When I melt snow I also boil it unless I'm worried about running out of fuel. I can put the boiled water into the thermos and drink hot water until my next meal stop or until it's empty. Even if it's not warm, it shouldn't freeze for many hours.

This got me to thinking about taking this idea to the next level. If I'm going to stop for lunch and boil water to drink, why not use this time to prepare extra food? I could boil both servings out of my favorite freeze dried meal pouch (since almost all of these come in 2 serving quantities). I'd eat one for lunch and put the other into a 500mL Thermos canister. I could then carry the canister (inside my jacket if needs be) and when I get to my destination I can eat without having to bust out the stove. I thought this would be a fantastic idea up here where the days are so short that by dinner time it's nearly pitch black outside. This would allow me more time to gather wood, set up a fire and the put up my shelter. I could start a fire instead and melt snow using that instead...since I'd already eaten there would be no rush to get the fire to the cooking stage...any ol' fire would do fine. I could even get to bed early (assuming I didn't need any more water) without ever having to dig out the stove OR light a fire and get an early start the next morning.

Have any of you tried this? It seems so obvious I have no idea why I've never done it before.

This is pretty much how the Canadian Army has done it for years and there are issued thermos which are the same size and shape as the water canteen so it will fit in the TAC vest. These only have narrow openings and are great for soups etc. As a general rule remember that nothing will stay hot for very long unless it goes in very hot. Preheating makes the contents last a considerable amount longer but Stews and foods with less liquid content lose their heat very fast even in the best thermos. Normal temp water still may freeze if left out in the Alberta cold overnight in a thermos (had it happen to me in Wainwright) but if heated enough before it goes in it will remain drinkable for quite some time. Anything with a Glass liner would end up broken very fast.

Thermoses are commonly carried by backcountry skiers and mountaineers to keep warm liquids handy without having to break out the stove and pot.
Yes a thermos would be a good winter item.
Bill

I wonder if you could melt snow/boil water IN a stainless thermos? Fill it up and just sit it on the stove???

Smart. If you are not doing it already (and I'm sure you are), run very hot water over the outside and fill the inside of the thermos with same to warm the cannister itself. This should prevent the cool metal from wicking a few degrees of heat away from the liquid you plan on ultimately fill the thermos with.

I like the Stanley models. You know the heavy metal ones that construction worker use.

Dave

Hi Hacksaw,

Thermos flasks are a great idea during winter hikes. Best to get a wide necked one though as they can be used for soups etc. The only problem is the larger stainless thermos flasks tend to be a bit heavy.


I now use a Lifeventure Thermal Mug 330ml. It weighs just over 300 grams. The Thermal Mug will keep its contents, usually Scotch Broth, nice and warm for about 6 hrs during winter day hikes. A Thermos will be slightly more efficient in retaining heat though, at around 8 hrs.
A neoprene water bottle cosy can keep water suprising warm for a few hours as well and helps prevent water from freezing during the night. A neoprene cover helps turn a the water bottle into a cosy hot water bottle by adding a bit of heat in the sleeping bag.

Edit - Actual weights are 0.5L Thermos - 323 grams = 1.54 Litres/Kg
Lifeventure Thermal Mug 0.33L - 292 grams = 1.13 Litres/Kg

The 0.5L Thermos is more efficient.

I bought two Thermos Nissan vacuum bottles. They are more expensive but really work. I put one with boiled water in the freezer overnight and when I open it it was still steaming.

Frankie

This is what I was talking about: http://www.stanley-pmi.com/shop/product_detail.aspx?ProductID=5 It will keep hot coffee hot all day in -0 weather.

Dave

I've found the wide neck of food flasks makes them a lot less efficient than flasks for liquid, the stopper isn't a vacuum insulation. You could liquidise your food and use a liquids flask.
The Sock

-0 degrees? wow, mine only keeps it warm all day in +0 degree weather what kind do you have??

Stanley. I will per-heat it with hot water and put some really hot water in it tonight and leave it in the car over night and see what happens in the morning.

Dave

No Kidding: http://www.amazon.com/review/product/B000FZX93K?filterBy=addFiveStar

Dave

OBG, no, you can't. The same properties that keep hot stuff hot and cold stuff cold is working against you. Just carry a metal cup.

Sue

agreed. The insulative properties would keep the heat out and away from the water...to the point where you'd likely damage the Thermos.

What you might be able to do is half fill it with hot water and fill it the rest of the way with snow or ice and let the temperature equalize. Very little heat would be wasted while this equilibrium took place...unlike boiling where as you melt snow and ice, the pot and the water within give off tons of heat into the atmosphere the whole time.

Thermos loaded with 98C water and put out into 6 degree F weather. I first gave it a 10 minute warm up period with some 90C degree water. We will see.

Dave

This is pretty much how I've always done it with a little modification. I have to eat a little more often so generally didn't heat up anything for lunch then do a mid-afternoon meal that I split up and used the other part for my supper.

By doing it later it's always stayed hot even in wide mouth containers and I can have a hot meal without much extra effort. Which also gives me some more flexibility on when I eat in the evening

I also like not having to rush and more time to explore/gather after I've set up camp.

Ok I went out to collect my Stanley thermos and I was kind of afraid that I might have ruined it by letting it freeze. I grabbed it and on heading back into the house I gave it a shake to see if I could feel a frozen ice chunk inside.

I got a nice vacuum "pop" as I removed the stopper and poured the contents out and it was still pipping hot. I would say it went in a little under 98C or 208F and it probably was 130F or so when I poured it out. The temp out side when I put the thermos out was 6F and it did warm to 13F overnight I would the thermos to perform just as well and you will probably use it in a 12 hour span.

I give it 2 thumbs up for sturdiness (it weights at least 1.5 pounds), you really can't break it easily, unless you drive over it and replacement parts are available at Walmart or Target. IIRC I paid 19.00 for my 1.1 quart.

Here is a link: http://www.stanley-pmi.com/shop/product_detail.aspx?ProductID=5

Dave