Gelatinizing Starch in an Emergency

I've been thinking more about disaster preparedness recently, and an important piece of that is food. And for many foods, before you can eat them you need to cook them. For example, a large fraction of the calories in our house are dry rice and pasta. These have ungelatinized starch, where the nutrition is bound up very tightly in starch granules. We mostly can't digest these as-is, but heat and water gelatinize the starch and make it bioavailable. [1] This means you need some way to heat things up. If the power grid is working then you have lots of options, including immersion heaters and boiling water with a kettle, but in many disasters this is not an option. What else can you do? Various options with fuel and batteries are possible, but a solar oven is hard to beat. Most would have what they'd need to put one together from tinfoil, cling wrap, tape, and cardboard. It would be worth putting some effort into identifying the best DIY-from-on-hand designs and distributing them. A simple one probably can't get water to the boil, but luckily you don't need that for starch: 180F is enough, and even 160F gets your pasta about halfway bioavailable. You do want to pre-soak, though: as starch gels it becomes less permeable to water, and without stirring or boil to disturb the surface gelling it may not fully hydrate. The main limitation of a solar oven is, of course, lack of sun. When I look at a place like Boston, though, you should be able to cook a pot of pasta on ~60% of days (~30% in the winter). If you have a mix of foods, including starches that can be eaten without heating, like crackers, cereal, and ramen, you can probably just eat those when there's not enough sun for the cooker. Alternatively a propane stove does pretty well: if you pre-soak, bring to the boil, turn the stove off, and move to an insulated container, you should be able to cook several hundred pounds of pasta with a standard 20lb propane tank. [1] Now, our stomach isn't the only way to get nutriti