Preventing the water in your canteen or water bottle from freezing can be a problem when the temperature is well below 0*C/32*F. It’s true that in this situation there’s a good chance there will be snow around which can be melted and used for drinking and cooking, but this isn’t always convenient or possible.
One way to keep a supply of liquid water with you is to use a thermos as a canteen. Everyone is familiar with using thermoses for their intended purpose of keeping hot drinks/soups hot, but they are also effective at preventing slightly warm or room-temperature liquids from freezing in the winter, thanks to their insulative properties. Just fill yours up with water at home before you head out or with boiled/filtered/treated water while in the wilds, just like you would with a regular canteen or water bottle, and you’re good to go. It’ll save you both time and effort!
By the way, did you know you can use a thermos to cook some foods as well? Just add the correct amount of boiling water and the contents of your favorite rice or pasta meal package to the thermos, shake it up well and hit the trail/woods. Your food will prepare itself without any chance of it burning and will stay hot for hours! I picked up this tip from The Backwoodsman Magazine.
And to my Finnish readers: hyvää itsenäisyyspäivää! :)