Originally Posted By wandering_daisy
You need to start the test with the temperature water you typically use backacking. It is amazing how much difference it makes. To save fuel I fill and solar heat a 2L platypus as soon as I get into camp. A few hours of sunshine will really heat it up, especially if you put a black stuff sack behind it. Heating breakfast water, cold from the night, takes almost twice as long. I have never had enough nerve to take the platypus inside my sleeping bag to keep the water warm for AM coffee.


Not sure if a Platypus would be right for the job, but I saw one youtube video where someone filled their Nalgene bottle with hot (but not boiling) water and put it in the bottom of their sleeping bag at night to keep their feet warm...Apparently it works very well. Not sure how warm it would be in the morning though.