I am generally against water bladders in winter. I don't really like them in summer either. smile Anyways, in winter I usually will bring water in a stainless canteen. When it is being stored, it is in a cozy I made from sleeping mat foam. When I store it over night, I turn it upside down and jam it into the snow. The snow insulates it, and if it freezes, chances are it won't freeze on the bottom. Turning it upside down makes the bottom the top, etc. Since it is in a metal container, it is easy to warm up/ thaw out.

If you have to have a bladder.....check out this video. This guy has an interesting take on it. It isn't my video, BTW.
water bladder in winter
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