Pressure Canner
All American, Presto, Mirro

with Sharon Peterson

How they work and why you should give this canning method a try.

Do you have visions of you pressure canner exploding and food covering your entire kitchen and ceilings? Have no fear... just have awareness. When used properly it is a perfectly safe piece of equipment.

Step by Step Instructions

How to use a pressure canner.
Step by step instructions.

Three Brands of Pressure Canners

Three main brands of pressure canners are popular on the market.

How a pressure canner works

Warning - You will see smaller pressure cooker/canners advertised on the market. In order to be safe your pot needs to be able to process at least FOUR 1-quart jars at a time. Any smaller than that and it is great for making supper, but not safe for processing food for storage.

Because of it's smaller size a pressure cooker has a shorter heating up and cooling down time. Thus, the total cooking time will be shorter even if you follow the recommended time lines. Stick with a standard size to be sure of safety.

Dial or Weighted Gauge Canner

There are two types of pressure canners; the dial gauge and the weighted gauge. Both perform the same task, only in slightly different manners.

The difference is the way they measure pressure. One uses a dial gauge and the other uses weights to control the amount of pressure build up.

The style pressure canner you choose is simply personal choice.

The Pot

Both weighted gauge and dial gauge pressure canners will have a base pot and a jar rack.

Unlike the rack of a water bath canner, it does not hang on the sides, it simply sets on the bottom and keeps the jars off the pot.

In this photo, my older dial gauge Presto is on the left, and the new weighted gauge Presto is on the right. I was surprised at the difference in size. Both canners hold seven 1-quart jars. However, my old pot is a bit narrower and taller than the new one. The jars fit more comfortably in the newer one with more room around them but the older style has more head room above the jars. Neither pot is better than the other, just different.

The Lid

Weighted Gauge Lid
Dial Gauge Lid

Both models have similar lids, however after closer inspection we see a few differences.

Overpressure plug

This plug is the safety net. If the pressure inside ever gets too high because of plugged vents this plug will open and release pressure.

Air vent lock

This opening allows air to vent or exhaust at the beginning of your processing time. As pressure begins to build the lock comes up and seals the opening. This vent lock is also a safety device that prevents us from accidentally opening the lid when pressure remains in the canner. It is a fail-safe, because it is IMPOSSIBLE to take that lid off until the pressure drops.

Any one of us could, without thinking, try to take off the canner lid just before the pressure was all the way down, but with that vent lock we are going to be spared the burns!!!

When the vent lock closes steam continues to stream out the vent pipe. You should allow this steam to escape for the complete venting time recommended in your directions. Usually 10 minutes.

Vent pipe:

On the weighted gauge, the weights set on the vent pipe. On the dial gauge a counter weight sits on the vent pipe. You'll notice this is separate from where the dial gauge sits. The two weights mentioned are different for each type of canner. Before each use, check the vent openings to be sure they are clear. You can visually check and/or run a string through the openings to clear out any obstructions.


Weights for a Weighted Gauge

canner wieght

This type of canner is set up so you will choose your own weight. Choose a pressure based on your altitude: 5, 10, or 15 pounds. Your recipe should tell you what pressure you need. 

The style of weights that I show here consists of the base and metal rings. The base and plastic tip without the rings will indicate 5 pounds of pressure, the base with one ring will indicate 10 pounds of pressure and the base with two rings will indicate 15 pounds of pressure. Add rings according to your required pressure.

When the chosen pressure has been achieved the weight will begin to rock. This indicates that the desired pressure has been reached.

Weight for a Dial Gauge

canner wieght

In this case the 'weight' is really a one piece counter weight. It is used to close off the vent, so pressure can build. It does not determine the amount of pressure build up. 

You will watch the dial to determine when the required pressure has been achieved, then adjust your heat level to maintain the level.

With a weighted gauge, you are limited to 5,10, or 15 pounds pressure. If your required pressure differs from these, you would have to choose the next higher level. For example if your required pressure is 13 pounds, you should use the 15 pound weight.

An will help you choose your pressure requirements.

You must have a dial gauge checked for accuracy. It is recommended that this be done once a year just prior to your main canning season. Extension services usually do this for a minimal fee.

The style you choose is simply personal choice.

Sealing Ring or Gasket

pressure canner lid gasket

Pressure canner lids have a sealing ring inside the rim. This gasket provides an airtight seal that allows pressure to build.

If you find you are loosing pressure and steam is leaking around the lid, this gasket is the culprit. Though they do last for years, it will need to be changed occasionally. Each year make sure the gasket is flexible and not cracked. If there is any doubt go ahead and check it before you have a load of food to process.

To do this simply fill your canner with 3 inches of water and bring to a boil. Place your lid and weights and let the canner build up a little pressure. As soon as you can see that the gasket is working and no steam is leaking around the edge of the lid, turn the heat off and let the canner cool. Do not lift off the weights or try to open the lid until the canner has come back to zero pressure. 

The All American pressure canner does not have a rubber gasket. The lids are made to clamp down tightly enough that a seal is not needed. It is recommended that you lubricate the lid with oil occasionally. Specific directions will be included with the care and maintenance manual.

Some things to remember

A dial gauge must be checked for accuracy. It is recommended that this be done once a year just prior to your main canning season. Extension services usually do this for a minimal fee. 

A weighted gauge is limited to 5, 10, or 15 pounds of pressure. If you required pressure differs from these, choose the next higher level. For example if your required pressure is 13 pounds, you should use the 15 pound weight. 

Remember, before each use check the vent openings on your canner lid to be sure they are clear. Visually check or run a string through the openings to clear out any obstructions.

New canners are sometimes fearful of their pressure canners. They have heard stories of explosions and big messes.

Please be reassured that your canner will not explode if you treat it correctly.

If vents get plugged the canners pressure will get too high and the over pressure plug will blow. Simply check the vents each time you process something and you should never have an explosion in your kitchen.

Online Canning Classes

Learn Home Canning

I've been teaching home canning for a long time.  I'd love to share what I've learned with you.  

Simply Canning School is what you need to start filling jars.

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by Sharon Peterson, Copyright © 2009-2020

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Any statements or claims about the possible health benefits conferred by any foods have not been evaluated by the Food & Drug Administration and are not intended to diagnose, treat, cure or prevent any disease. You are encouraged to verify all canning and food preservation advice on the USDA food preservation website. 

See my Full Disclaimer here.