Rudolph wrote:I do question the statement that heating the water for two meals is quicker and more fuel efficient than heating one after the other. I reckoned it was the other way about.
Yeah, I pondered this for a while (as you do) and would love to hear your reasoning. I'm no scientist, but I decided that the thermal energy required to boil 2 litres of water is the same whether it's in two 1 litre pots or one 2 litre pot, so heat loss variables should be considered. As well as heating the water you'll also need to heat the pot, and in a real-life situation once the first 1l of water has boiled and you've messed around pouring the water into the pouch, the pot (and anything else that gets hot) will have cooled, and require bringing up to temperature again. Meths stoves will also require you to wait for the stove to cool before relighting (unless you leave it burning, but that's not particularly fuel efficient). Smaller capacity pots tend to have smaller external dimensions, which can lead to an inefficient use of heat if the flames are licking up the side of the pot - a wide and shallow pot is best. Of course, two stoves and two 1l pots may be the most fuel efficient, but then you'd have to carry two stoves.
If you're a two-course hot dinner person boiling two consecutive pots of water may be more practical, using the first boil for your main course, and then boiling a further pot whilst waiting for it to rehydrate. Timed right, the second pan of boiling water can be added to your dessert just as the main course is ready, and the dessert rehydration will be complete when you finish your main course. There's something to practice now that the nights are drawing in!