Crisps, a growing segment of snacks, require a different expansion technique than frying, hot-air popping or extruding. Items such as Popchips, produced by J.R. Short Milling Co., Kankakee, IL, are created using micropellets. Shaped like so many small split peas, the pellets undergo a controlled expansion that fuses the pellets together.

The micropellets sit inside a depression where a piston hits them. The resulting heat and pressure create a controlled explosion that expands the micropellets and fuses them together into crisp snack.