I have long believed that quality hot water bottles and steel vacuum thermos bottles and are very valuable survival tools. They are a wonderful intersection of high and low tech that can serve in a number of helpful roles.
THERMOSESFireless Cooking (retained-heat cooking) - I have cooked in WIDE-mouth thermoses many hundreds of times since the 1970s. There are a couple of other articles on this sight covering that fuel-saving application. I would amend the recommendation given re: Aladdin Stanley vacuum bottles, and I will cover that below. Using WIDE-mouth thermoses for “fireless cooking” is one very useful role for thermos bottles that saves fuel and allows mobility even while your food cooks. Summarized, fireless cooking in a wide-mouth thermos involves immediately transferring boiling-hot food into the thermos which is then sealed up for approx. two to three hours. It won’t burn or over cook the food. If the food temp drops over time into double digits fahrenheit, the food will eventually begin to spoil. If cooking grain, leave a half inch space empty at the top for expansion. If it is to be carried in a pack it should be maintained upright and placed within a plastic bag which can be secured against leakage. I’ve learned that the hard way.