Popping to perfection

Ever wondered why you get that "crunch" from an unpopped popcorn kernel when you are munching on popcorn at the cinema? It's all down to the chemical change that takes place in the kernel.

The kernels must contain moisture on the inside (a minimum of 14.5% by mass) which will become water vapour when heated, which has a much larger volume and eventually the kernel's outer coating will not be able to contain the pressure build up. That's the pop.

It relies upon the "hull" of the kernel undergoing a chemical change. The cellulose structure changes to become more crystalline when heated, which is great for allowing a high pressure build up inside the kernel (keeps the moisture in, allowing it to expand sufficiently to cause that magic "pop".)

The best poppers have a cellulose that is especially good at turning into crystalline sheets, so that the water is contained inside the kernel when heated, instead of leaking out and leaving just the hard shell for you to crunch on! Read here for the full article.