Pressure Canning

The definition of pressure canning

Pressure canning is one of the two methods used for home preservation of food in jars.

Pressure canning involves sealing food in jars, then putting the jars into a large, pressurized pot that raises the temperature of the food products inside the jar far above boiling for a given period of time. Typically, home pressure canning is currently done at 115 C (240 F).

Three things are done to the jars as a result of this simple process: 1

  1. Removal of oxygen: The jar expels any oxygen inside it which could spoil food;
  2. Heat sterilization: Any nasties that could interfere with food safety are killed off;
  3. Sealed jar: As a result of the expelled air, a vacuum seal is created inside the jar so that nothing can re-enter the now sterile environment inside the jar.

 

Pressure Canner History

Pressure canners for a time had a competing technical: adding calcium chloride (which is now used to crisp pickles) to the water instead to raise the temperature:

[Appert] did experiment with pressure processing, but at that time ‘digesters’ were quite dangerous, and it was not the norm. Around 1863 processors used ‘chemical baths’, in which high concentrations of calcium chloride enabled ‘water’ to boil at up to 121 C. This allowed for significantly shorter cooking times. By 1870 basic retorts were being used to temperatures up to 121 C but they were still quite dangerous and hand operated.” 2

During World War Two, pressure canners in America were limited by rationing.

A limited number of pressure canners – the size to process seven quarts at one time — are being manufactured and distributed by rationing. There are not nearly enough steam pressure canners to go around. But if individuals and groups owning canners share them and keep them working at capacity, steam pressure canners will preserve millions of jars of food. If you have no steam pressure canner, team with someone who has. Or go to a community food preservation center. Or if you would make extra good use of a canner, apply through your county farm rationing committee to buy one.”3

Pressure canner brands

See separate page dedicated to pressure canner brands.

Further Reading

Utah State University Cooperative Extension. General information about pressure canners (Link valid as of spring 2015.)

Pressure Canning Information

Can I just pressure can everything instead of water bathing?

Can I just pressure can everything instead of water bathing?

When you first take the step of getting and using a pressure canner, it's typical that you want to pressure can everything instead of water bathing. But, you can't. Oh, it's not a safety issue. You won't kill anyone. But they might kill you, because...
Dirty lids after pressure canning

Dirty lids after pressure canning

Often, the lid on whatever jar in the centre of the pot under the gauge comes out looking as through it's been through a war zone. It will happen both to standard single-use metal lids, and to the resusable Tattler lids. It cleans off the Tattlers ...
Minimum jar load for pressure canners

Minimum jar load for pressure canners

Until now, attention has always been focussed on what the minimum physical size a pressure canner can be, and on what the maximum number of jars we can all cram into a canner load is. Now, Ball has issued advice on what the minimum allowable number...
Mirro Pressure Cooker & Canners Instructions Manual & Recipe Book

Mirro Pressure Cooker & Canners Instructions Manual & Recipe Book

  We provide this link to the Mirro manual as a courtesy because people have a hard time finding it online. This is not an endorsement of the manual as a whole. We'd recommend that you consider referring to it only for operation and maintenance...
Pressure Canner Altitude Adjustments

Pressure Canner Altitude Adjustments

As altitude increases, the temperature that can achieved at a given pressure will decrease. Consequently, as altitude increases,  you have to also increase the pressure inside the pressure canner to reach and maintain a desired temperature. You ...
Pressure Canner Brands

Pressure Canner Brands

A pressure canner is an essential tool to have when a home canner wants to expand his or her range of knowledge and skill. Yet, it can be a leap at first. While not overly expensive, it's not cheap either, and does require storage space, so a home ...
Pressure Canner Gaskets

Pressure Canner Gaskets

Most pressure canner brands (as of 2015) use rubber gaskets inside the lid cover, to help seal in pressure: A pressure canner is a deep, heavy kettle that has a rack on the bottom for jars to stand on, a tight-fitting lid with a gasket, and a pressure...
Pressure Canner Heat Source

Pressure Canner Heat Source

Sometimes concerns are raised about the heat sources for pressure canners. The concerns can be summed up as follows: Bottoms of canners Pressure canners with concave bottoms (Mirro models) can't be used on flat stop stoves because the heat won't...
Pressure Canners: Dial Gauge or Weighted Gauge?

Pressure Canners: Dial Gauge or Weighted Gauge?

The pressure on a pressure canner can be controlled in two ways: A dial gauge shows you what the pressure is, and you control the pressure using the stove burner knob to adjust the heat up and down as needed to raise or lower the pressure; OR...
Pressure Canners: When size matters

Pressure Canners: When size matters

Minimum Size of Pressure Canners The smallest size of pressure canner that the National Center for Home Food Preservation and the USDA are willing to call "canners" are pressure canners that can hold a minimum of 4 x 1 litre (US quart) jars. This...
Pressure Canning Fish and Seafoods

Pressure Canning Fish and Seafoods

There is no safe method for canning fish and seafood other than pressure canning. Guidelines for pressure canning fish and seafood are online on the National Center for Home Food Preservation's page for meat, fish and seafood, and, are in the...
Pressure Canning Principles

Pressure Canning Principles

 What foods is pressure canning used for? low acid; meats; poultry; seafood; soups; vegetables (generally all); mixtures of low-acid and acid foods (e.g. spaghetti sauce).   What is it about pressure canning ...
Pressure Canning Step-by-step

Pressure Canning Step-by-step

Pressure Canning Procedures Here's a step-by-step guide to how to use a pressure canner. If you're looking for information on the "why" -- as in, what's the theory and the reasons behind all these steps, see our page on Pressure Canning Principles...
Pressure Cookers versus Pressure Canners

Pressure Cookers versus Pressure Canners

Pressure canners are a range of pressure cookers, but they are pressure cookers on steroids. Pressure canners are not the same thing as pressure cookers, and it is important to understand the difference. Pressure cookers or pressure saucepans are...
Pressure Gauge Testing

Pressure Gauge Testing

Over time, the dial gauge on a pressure canner can become inaccurate by showing either too high or too low. If the dial shows lower than the actual pressure, then that means you will be running the pressure too high and over-processing your food,...
Presto Canners

Presto Canners

The Presto Pressure canners are one of the big three brands of pressure canners. The Presto canners also do double-duty as water-bath canners, so if you have one, you don't need to buy a separate water-bath canner as well (though note further down...
Presto Pressure Canner 3-piece Regulator Weight

Presto Pressure Canner 3-piece Regulator Weight

Presto makes a 3-piece adjustable weight that can "convert" your Presto Gauge Pressure Canner into a dual-gauge pressure canner, like the All-American. It's a 3-piece weight that adjusts easily to 5, 10 and 15 lbs of pressure; the Presto part number...
Presto Pressure Canner Accessories

Presto Pressure Canner Accessories

Most people who purchase Presto pressure canners end up, sooner or later, purchasing one or both of the following two accessories, which are sold separately. These two accessories will change your canning life -- seriously. Note: when shopping...
Presto Pressure Canner Gauge Testing

Presto Pressure Canner Gauge Testing

Presto Pressure Canner Gauge Testing If you get the Presto 3 part weight , you don't need to get your gauge checked yearly -- or ever, really. The weight becomes all that you need to rely on. That being said, even those who have the 3-part weight...
Presto Pressure Canner Manual

Presto Pressure Canner Manual

  It has become fashionable in some "Safe Canning Groups" to slag all manuals that come with all pressure canners. The Presto manual comes in for this disregard. In the category of "a little knowledge can be misleading", the experts who...
Presto Pressure Canner Replacement Rings / Gaskets

Presto Pressure Canner Replacement Rings / Gaskets

The Presto Pressure Canners require a rubber gasket (aka sealing ring) to go inside their lids. It will need replacing from time to time. The lifespan of a gasket and plug depends upon the amount of pressure canning you do. For Presto models.... 01745...
The cool down process is important in pressure canning

The cool down process is important in pressure canning

Don't try to rush the cool down period after a pressure canning session. It's actually vital for both food safety and food quality. Let it cool naturally. You can remove the canner from the burner and slide it over to another burner, if you...
Why is 10 pounds and not 15 pounds the base for pressure canning?

Why is 10 pounds and not 15 pounds the base for pressure canning?

Commercial sterilization of canned goods is done at  15 pounds pressure / 250 F [103 kPa / 121 C], which consequently requires a far shorter period of processing time. We can achieve 15 pounds pressure in our home pressure canners, but all home p...

 


  1. Andress, Elizabeth. “History, Science and Current Practice in Home Food Preservation.” Webinar. 27 February 2013. [42:00] Accessed January 2015 at http://nchfp.uga.edu/multimedia/video/nchfp.wmv  

  2. Featherstone, Susan.  A Complete Course in Canning and Related Processes: Volume 2. Cambridge, England. Woodhead Publishing. 2014. Page xxxi. 

  3. Wartime Canning of Fruits, vegetables. USDA Bureau of Human Nutrition and Home Economics. Washington, DC. June 1943.  

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