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University of Illinois Extension

Unsafe & Outdated Canning Methods

  • Open-kettle method; no processing was done, unsafe
  • Sealing jams, jellies, preserves, and butters with wax or paraffin; often allows harmful mold growth. Print a Fact Sheet on mold.
  • Do not use recipes from celebrity chefs and unreliable internet sources; often use unsafe, outdated, non-research based methods
  • The only safe and approved method is using the Water Bath Canner method (See Using a boiling Water Bath)
  • Do not invert hot jars of jam, jelly, etc.
  • Steam canning; inadequate research for processing times
  • Do not use microwave oven, electric oven, slow cookers, crock pot, convection oven, dishwasher, or sun canning methods
    • These methods can be extremely dangerous and are not allowed for processing jams, jellies, butter, and preserves for CFO
  • The only safe method is using the Water Bath Canner method