Not all corn will pop correctly. In fact, it takes a kernel with an especially tough outer shell to produce the puffy pieces you know and love. When you heat these kernels to the right temperature, steam builds up inside. Eventually, it explodes like an overheated boiler, forcing the starch inside out into irregular puffs.

The popping process doesn’t work right every time. Some pieces of popcorn have weaker shells that allow steam to leak out. That keeps them from exploding on cue. Others don’t have enough moisture inside them to produce the right amount of pressure. The starchy interior of the corn stays locked inside and your popcorn bowl remains full of hard kernels. According to NBC News, cheaper brands of popcorn tend to have more leaky kernels -- for a nearly 47 percent failure rate.

Reduce the number of unpopped kernels in your next batch by storing it correctly. Always keep yet-popped popcorn in an airtight container at room temperature, not in the refrigerator or the freezer. These appliances can actually leach moisture out of the popcorn, making it more likely to burn instead of popping. If you have a batch of popcorn that is stale or dried out, soak the kernels in about a tablespoon of water for every 3 cups of unpopped corn. After a few days, the corn should absorb the moisture, making it easier to pop.

While it’s best to make sure your popcorn is in good popping condition, a few kernels are always destined to fail. If you want to try repopping them, save the duds in a separate container. Once you have enough, place them in a paper bag and microwave it on the popcorn setting. At least some of the kernels should pop. Just make sure you stop the microwave about a minute early to reduce the chance of burnt corn.