I saw a whole stack of these at the grocery store a few weeks ago and the first thing through my mind wasn’t “Hum, I wonder if the coffee tastes good?”. Hell no! It was “Oh yeah! Self heating cans! I have to buy a few and take them apart!” Well my lack of money got the better of me and I put the idea of exploring new tech away for a while. I figured it was an exothermic reaction of something coming in contact with water. I used to play with that when I was a kid. I have a bit of fun my heating cupric sulfate over a flame until it turned from blue to white. Once it was cooled if you added water to it you would get quite a bit of steam and some nice ‘SSSS’ sounds to boot! What fun. Well, I lived in the sticks what else was I going to do? (Someone ask me about ‘ Pink Fizzing Smoke’, now that was fun! 🙂 )
I know you get the same thing from one of the heaters in an MRE, but that uses iron powder to do the same thing. I think the by product of that is hydrogen though. Not what you want being generated in your car on the way to work. (“Mmm, that coffee sure smells good [FWHUMP!!!] AIEEE!!!” Yeah, that would be PR nightmare wouldn’t it?)
These use calcium oxide and water to make heat, I don’t think there is any gas created by this reaction. Any chemists out there care to comment?
MAKE has a great pictorial on how the new Wolfgang Puck self heating coffee cans. Go buy a few before they are all recalled because of an idiot who can’t read the directions.
Wolfgang Puck self heating can hacking…