For some strange reason I thought of using medical ice-packs to cool drinks after long expeditions and hikes. I googled around and found that ammonium nitrate (one ingredient of gunpowder) can be used too since it does absorb quite a bit (my estimate is about 26kJ) of energy when dissolved in water. Might be enough to cool a few beers. Wonder where I can get some medical ice-packs in Malaysia?
