What is the difference between pressure canning and water bath canning?  Temperature!  A very high temperature to be exact.  Pressure canning allows the heat inside a pressure canner to build up to 240*F.  The water bath method uses boiling water, which only reaches 212*F, and even less if at higher elevations.  Something magical happens when a pressure canner processes food at 240*F… both bacteria AND botulism spores are killed!

While boiling will kill bacteria, the lack of bacteria and anaerobic environment of a water bath processed jar is the ideal environment for botulism spores to grow.  This is important because non-acidic foods, like meat and vegetables, are susceptable to develop botulism while canned and sitting quietly your food storage.  Acidic foods, like fruit, do not develop botulism because of their acid content.  It’s perfectly safe to use a water bath (boiling) for canning fruits. Vegetables, including tomatoes (because the acidity level is in question batch to batch), should be pressure canned. 

I love my pressure canner.  A pressure canner can be used for water bath canning as well (just leave the lid off), so you only need the one piece of equipment.  It can safely preserve anything from applesauce to venison without me having to worry about food safety.  There are only a few precautions:

  • Do not use a pressure cooker instead of a pressure canner.  They are different equipment.  The cooker will not heat as high as the canner.
  • Do not remove the lid from a pressure canner while canning.  Extremely hot steam is building in pressure inside the canner.  If you open it in the middle of canning, ridiculously hot water will explode all around you, and you will most like suffer intense burns from it.  Please use common sense.  You may be severely injured from the steam.
  • Do not can on a wood stove or wood cook stove.  It is very difficult to maintain a constant temperature on a wood-fired stove.  Without a constant heat source, the contents inside the jar may still grow bacteria or develop botulism.  Try a portable propane stove for canning if you primarily cook with wood.
  • Never use the “open kettle” method for canning.  This is when you fill a jar with hot food and let the steam from the food make the seal.  While you may get a decent seal, the contents have not been heated high enough to prevent either bacteria or botulism from growing in that jar of food.
About the Author Homesteading Mom

Homesteading Mom is run by Cat Ellis, an herbalist, prepper and aspiring homesteader. Cat is the author of two books, Prepper's Natural Medicine and Prepping for a Pandemic. Cat Ellis also blogs at KetoCat.com, HerbalPrepper.com, and TheOrganicPrepper.com.

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