Sometimes a jar in a canner load fails to seal upon cooling. This may happen because of a cracked or nicked jar, or perhaps because food is fouling the jar rim where the lid sits. Due to loss of quality, reprocessing of jars is not recommended.
If you do reprocess, follow these steps for a safe product:
- Re-process within 24 hours. For a safe final product, you must have followed an up-to-date research-tested recipe on your first attempt, and you must reprocess within 24 hours.
- Remove the lid and empty the contents of the jar into a large pot and heat to boiling.
- Fill a clean jar with the heated food, remove air bubbles, and top with a new lid.
- Reprocess using a tested recipe for a hot-pack product. If there is no tested hot-pack recipe, the product may not be safely reprocessed.
If you did not follow a tested recipe on the first try, all jars, sealed or unsealed, may be unsafe and should be discarded.
To preserve quality of food where jars failed to seal (and discovered within 24 hours of initial canning), refrigerate the jars and consume contents within one week. Unsealed jars may also be frozen for up to one year, be sure to adjust headspace to one inch before freezing.
Source: National Center for Home Food Preservation – Newsflash
