NDSU Extension Service - Ramsey County


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Questions and Answers about using a Pressure Canner

Questions and Answers About Using a Pressure Canner

Pressure canning is recommended for low-acid foods. Low-acid foods are not acidic enough to prevent the growth of bacteria and should be processed at temperatures of 240 degrees to 250 degrees, which is attainable with pressure canners.

Low-acid foods include:

  • Red meats
  • Seafood
  • Poultry
  • Milk
  • All fresh vegetables except for most tomatoes

These foods have a pH value higher than 4.6. Mixtures of low-acid and acidic foods also have pH values above 4.6 unless their recipes include enough lemon juice, citric acid or vinegar to make them acidic.

What Are Some Common Errors Using a Pressure Canner?

Air trapped in the closed canner during processing.
Air trapped in a pressure canner lowers the temperature and this results in underprocessing. To be safe, all pressure canners must be vented for 10 minutes before they are pressurized.

Using an inaccurate dial gauge.
Gauges should be checked for accuracy each year before the canner is used. If the gauge reads high or low by more than 1 pound at 5, 10 or 15 pounds of pressure, replace it. Weighted gauges are always accurate. If your canner has both a gauge and weight, go by the weight, using the gauge as a guide.

How Should a Pressure Canner be Stored?

Make sure your canner is clean and dry before storing it. Air should reach the inside of the canner to prevent a stale odor from forming. Put crumpled paper inside the canner and wrap the lid in paper or place it in a paper bag. Turn the lid upside down in the canner instead of sealing the canner shut. If storage space is available, place the lid in a paper bag and store it right side up on a shelf.

For more information on this and other topics, see www.ag.ndsu.edu.
(Click on "Nutrition, Food Safety and Health," then "Food Preservation and Storage")


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