Nescafé self-heating coffee is
exactly what it says on the tin. It comes in a 330ml can, it's coffee and it heats itself. It is designed for people who need hot coffee
anytime, anywhere. It comes in white, and white with sugar flavours.
The can contains a heating element in the base, which contains water and calcium oxide (quicklime). To heat the coffee, a button in the base of the can is depressed, which allows the water and quicklime to react, producing an exothermic reaction.
calcium oxide + water = calcium hydroxide + energy
CaO(s) + H2O(l) = Ca(OH)2(s) + 66 kJ/mol
The reaction heats the coffee to an optimal temperature of 60 degrees C.
The product, called the Thermotic Can, was designed by Thermotic Developments Limited in 1996, was developed at the University of Southampton, England, and is marketed by Nescafé, owned by Nestlé, the world's largest food company. However, the idea is not a new one. Armed forces in 1939 used a self-heating can that burned cordite to create the heat.
The coffee itself is nothing special. While there are benefits to heating coffee with a controlled heating process (apparently boiling water scalds the coffee and spoils the taste), it has a taste reminiscent of roast potatoes. Also, it is overpriced, presumably to regain development costs, and while the can is the standard 330ml size, much of it is taken up with the heating element.
I am not a chemist. If the chemistry above is wrong, let me know and I'll fix it.