One of the benefits of air popped corn is that it can stay fresh and crisp much longer than oil popped because there are no oils to saturate the corn and eventually become soggy and/or rancid.

However, you do need to take greater care in regards to environmental conditions when air popping.

Once the seed pops, it is very hygroscopic; meaning it will easily absorb moisture. This is especially true when it comes to air popping. The same oil that makes fried corn eventually soggy also offers some protection from moisture in the air.
Most people don't realize that popcorn seeds are roughly 13% moisture by weight. This might not matter much when popping corn in small batches, but when you have a high speed Vortex air popper it can really add up quickly.

Consider that our smallest machine will pop 25 lbs of seed an hour, and our largest pops up to 220 lbs per hour. This means, that depending on the machine, you're potentially adding between 3.25 lbs to 28.6 lbs of water into the air per hour.
If you don't manage this moisture, it will want to soak back into the popped corn, making it soggy and/or chewy.

Simple Steps to Crispy Perfection

Fortunately, there are simple solutions to combating this problem and making the crispiest corn possible:

1) Make sure you have an exhaust hood/vent above the output sifter of the machine to remove as much of that moisture out of your environment as possible.

2) If that's not enough, then consider a dehumidifier for your popping room as well.

3) Keep in mind that Humidity is actually Relative Humidity and this means that the warmer the room, the more moisture the air can hold. The solution is to keep your room cool, especially during the more humid months. We keep ours at around 68 degrees but know other processors that aim for as low as 65 degrees.

4) If you are storing your popped corn for any length of time before bagging, be sure to use moisture proof bins or barrels.

5) Don't pop at a higher temperature than necessary. Realize that popping at a very high temperature may pop seed somewhat faster and slightly reduce orphans, but at the same time it will slightly reduce the size of the popped corn while also making it over dried, and as a result both tougher and chewier than it needs to be.

There's no correct temperature for popping corn as the seed and local environment will both dictate the best choice. Instead, it is on the producer to choose quality seed and to test various popping temperatures in order to determine the lowest temperature setting that will produce satisfactory results.

Follow these simple suggestions and you'll be able to make crunchy popcorn that will store and/or be shelf stable for an exceptionally long time.

When it comes to packaging, it's important to realize that a single layer plastic bag is not as resistant to both oxygen and moisture transfer as most people seem to think. They are fine for same day vending or short retail shelf life, but they won't keep popcorn fresh for long periods of time.

If you need shelf-stable popcorn, be sure to talk to packaging vendors about their options for multi-layered bags, including foil lined. For the longest life, ask packaging equipment providers about machines that offer "nitrogen replacement" during the packaging process as well.