I have been trying various foods--ramen, rice noodles, dehydrated mushrooms, and these at least rehdrate quickly at room temperature, no need for heat. I played with a pack mounted solar water heater--Had a black mesh bag that could be attached to top of pack, in it went an inflated gallon ziplock. a piece of the mesh was cut out so that light got in, but bag stayed in mesh. Got one of the twist top containeers with a dark blue top. Water went in it, upside down. Cut out black mesh draped over this inside inflated gallon bag, inside mesh bag. Slow in VA sun, and I don't nee hot food, just loose a little crunch and I am happy. Take a little piece of everything you might want to rehydrate in water and test at 30 minute intervals. david