On another thread, Larry Ledwick mentioned cooking in a thermos bottle.
You can also help hot foods steep and heat soak by taking them off the flame and wrapping them in a cotton towel so they don’t quickly cool. Similar to the thermos cooking I mentioned a while back. Heat the food to 165-185 deg and pour in a small lunch box size stainless thermos and let it sit for 10 minutes or so instead of wasting fuel trying to bring it to a simmer or boil.
So today I was out buying a 250 gram butane canister for a camp stove, and there on the shelf was a nice 24 oz. Stanley brand wide mouth stainless steel thermos for $22.xx (plus 9%+ California sales tax). About $25 out the door. I couldn’t resist the opportunity to experiment…
At home, I’ve now done my first thermos cooking experiment. I brought a small pan of water to the boil, and put some 3 inch long pieces of tubeti (think long macaroni) in it. Brought it back to the boil, then poured it through a canning funnel into the thermos. Lid on, let it sit about 14 minutes.
Upon opening, the measured temperature was around 190-195 F. So about a 17 F drop in the pouring and standing steps. I poured “the works” into a sieve to drain, then put the noodles in a bowl. A bare noodle was properly cooked, but with a slightly soft surface. Not quite “gummy”, but not as smooth as noodles cooked at a boil. Good enough, though. With Alfredo sauce and some chopped bits of cooked ham added, it was quite nice. I just dumped the sauce, from a refrigerated jar, onto the noodles and let the residual heat from the noodles warm the sauce from refrigerated temperature to “nice”.
If something really needs to be boiled, this will not quite get there. A preheat of the thermos with boiling water may get close enough.
“Slow Cooker” recipes ought to work OK. Just get it to the simmer / boil point, pour in, and wait about 8 hours. (This particular thermos claims a 15 hour hot temperature hold time)
It is a little hard to clean the thermos. I used a “bottle brush”. This isn’t going to be a main form of cooking for me just because I’d rather just run pots through the dish washing machine. Hand washing a thermos with a bottle brush to get out beef stew is not my idea of fun. (If anyone knows of a dish washer safe thermos, put up a note!)
It would work well as a fuel saving method “on the trail”, but it would take a lot of fuel savings to make up the weight. In a “survival” at home situation, it would be a good way to extend fuel, but at the cost of wash water. Cooking watery things would clean easier than those with a gravy.
It might work best to use an immersion heater (those small cup heater coils, if they are still made) to raise the contents to the boil inside the thermos for best cooking. In a pinch, what it does with the heat-then-pour is good enough for a lot of foods. Cut food into small pieces so you don’t have a big cold lump in the middle of a chicken leg causing equilibrium temperature to end up something like 150 F and growing cultures of “chicken germs”.
I’m now going to set about trying several different recipes to see what works. If anyone has known working recipes, post ’em! Oh Joy, a new kind of cooking to explore! ;-) Worth far more than $25 just in entertainment value… There are several web pages that claim to be recipes but that’s going to take a while to work through:
A “Thermal Cooker”, like a pot sized thermos: