When I'm out camping in the winter, I take a flexible drinks pouch and get it filled with boiling water at the last pub before pitching camp and bedding down. Works well as a hot water bottle, and makes the first brew of the day less of an effort.
Nalgene bottles are good for this too, rated to be safe with boiling water. A couple of these in ski socks in the sleeping bag at night kept us toasty in Nepal.
When I'm out camping in the winter, I take a flexible drinks pouch and get it filled with boiling water at the last pub before pitching camp and bedding down. Works well as a hot water bottle, and makes the first brew of the day less of an effort.