It’s Canning Season: Tips for Safety

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picture of pressure canners with jars of greenbeans and carrotsWith the summer months here, there is more and more fresh produce available. Many are looking for ways to preserve it to have to eat later in the year. Here is some information about preserving fresh foods for later by canning them safely.

Fresh foods are perishable because they contain a high percentage of water. The practice of canning preserves fresh food by removing oxygen, destroying enzymes, and preventing the growth of bacteria, yeasts and mold. The type of canning method, Boiling Water Canning or Pressure Canning, is determined by the pH or acid level of the food you are canning.

The low-acid foods or foods with pH above 4.6, must be canned using the Pressure Canning method in order to destroy Clostridium Botulinum, which can be deadly. C. Botulinum will not release the toxin which causes illness if the environment is high acid or when there is oxygen available. Once we seal the jars during the canning process, the environment within the jar is anaerobic and if low acid, it will promote the growth of C. Botulinum and be a risk for becoming ill unless it is destroyed. We do this by getting the contents in the jar to 240°F. This is only achieved through pressure canning.

To safely can, we need to adjust our canning process when we live at higher altitudes, due to the fact that our water boils at a lower temperature. See the information below for adjustments when pressure canning and boiling water canning.

For dial-gauge processing changes:

  • 0-2000 feet                            11 pounds pressure
  • 2001-4000 feet                     12 pounds pressure
  • 4001-6000 feet                     13 pounds pressure
  • 6001-8000 feet                     14 pounds pressure

For weighted gauge adjustments

  • 0-1000 feet                            10 pounds pressure
  • Greater than 1000 feet        15 pounds pressure.

Boiling water canner adjustments

The processing time will increase because the water starts to boil at a lower temperature.

  • 1,001 – 3,000                                   add 5 minutes to time
  • 3,001 – 6,000                                   add 10 minutes to time
  • 6,001 – 8,000                                   add 15 minutes to time
  • 8,001 – 10,000                                 add 20 minutes to time

For more information about safe canning and safe recipes, go to NC State University: Safe Plates:  Canning Fact Sheet or The National Center for Home Food Preservation. You can also contact Cathy Hohenstein, FCS Agent at our office at She is available to meet and share more information or to check the pressure canner dial gauges for accuracy.