Hmmm, I carry one of those pocket thermometer thingies (to use a technical term) that is used so I don’t have to guess how hot or cold water happens to be. Does anyone know the temps required to kill the various bacteria, virus’s or other pathogens? If you know the temperature that kills them, you don’t have to be concerned about elevation lowering the boiling temp of water, or extending the time so long there’s no water left in the container.