Passing through the local Farm Store yesterday I spied what I initially thought was a great invention - self heating cans of things like hot chocolate or tomato soup. Push a button and let 'er heat up for 3 minutes.

What a great idea for a weekend where near single digit temp's are forecast and my son and I will be deer hunting. Steaming hot chocolate 3 minutes after pressing the button via a chemical reaction; I assume, need to check out www.hot-can.com for the actual details....

What a splendid product..... until I popped near 3 USD per can, and read the fine print after I got home. DO NOT store in temperatures outside the range of 50-90F. Who on earth wants hot chocolate when it is a balmy 80?

They almost knocked one outta the park. Almost.

sorry but I couldn't help myself

It's a pure chemical reaction. X amount of water added to Y amount of reagent produces Z amount of energy. The reaction creates enough energy to increase the heat of the container the same amount every time. If they start at 35 degrees, it will produce a warm, not hot drink or soup. Less than freezing their is no reaction. If it is stored in a hot envirionment it can get dangerously hot.