Mushroom / Brains popcorn kernels pops into a more solid, round popcorn, like the top of a mushroom. (we call them brains because they kind of look like brains!) This type of popcorn is excellent for caramel popcorn or popcorn coated in glazes and toppings. Its pieces are stronger than butterfly-shaped popcorn and won’t easily crumble when you mix in these types of toppings. These kernels are not recommended for hot-air poppers because they have a thicker hull that requires more heat than most consumer hot-air poppers put out.