Natural Hog Casings are shipped and stored unrefrigerated. Store in refrigerator when received and they will last up to 2 years (if package is airtight). Once opened, unused casings can be stored in a brine solution or granulated salt in original resealable pouch. Refrigerate unused casings. Do not freeze. Use within 3 to 4 weeks. Collagen Casings can be stored up to 2 years if unopened. Rehydrate in refrigerator overnight to reconstitute. Once opened, unused casings can be stored up to a year, in resealable pouch and stored in a refrigerator. Fibrous Casings can be stored 2 to 3 years or longer.