How Long Does Popcorn in a Tin Stay Fresh?
Once you open your popcorn tin, it can stay fresh for up to two weeks if stored properly. If you seal it, it can last for three weeks.
However, your popcorn in a tin can stay fresh for up to two months if you keep it unopened in the original tin in a dry, cool place. Keep the popcorn in its original tin or airtight plastic or glass containers with sealable lids to preserve freshness.