Pressure Canners

A pressure canner is a pressure cooker that is large enough to hold quart jars.

I still remember my mother sternly admonishing me not to mess with the pressure cooker, because it can explode. She did indeed succeed in scaring me enough that I decided to keep my distance from the pressure cooker. On the other hand, that fear was counter balanced by the fact that my mother used the pressure cooker countless times without any problem. The end result is that I am not afraid of pressure cookers, but I am afraid of people who don't read and follow instructions.



Since pressure canners vary from one model to another, I won't pretend that anything I write can replace the instructions that came withyour pressure canner. However I would like to write a little bit for people who may not have ever used a pressure cooker before.

Backup Safety Valves

New pressure canners have one or more backup safety valves in the lid. If the petcock (which is the primary safety valve) becomes plugged, then one of the backup valves will pop open to release steam.

A pressure canner that is more than about 30 years old might not have any extra safety valves in it. If you choose to use such a canner, then it is extremely important to keep the petcock clean and monitor the pressure.

Petcock

The petcock (which is also called a steam vent or a steam pipe) is the primary safety feature on a pressure canner. The backup valves should only come into use if the petcock is plugged. If your pressure canner did not come with a cleaning rod for the petcock, or if the cleaning rod has been lost, then pipe cleaners work well.

Dial Gauge or Rocker Weight

Pressure canners that use a rocker weight seem to be becoming less common all the time. This is probably because they are harder to learn to use. The one advantage that they do have is that they don't loose accuracy over time.

Dial gauges on the other hand, can loose accuracy. You should have them checked annually. The owners manual will usually give you an address that you can mail the gauge to and have it checked for free. I think the Presto corporation will check any model (not just their own). Alternatively, your USDA extension office may be able to check it or tell you where it can be done locally. You can find the nearest extension office with this map
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Lid

The way the lid is fastened depends on the model. Be sure that the lid is always fastened properly and do not remove the lid until the pressure has returned to zero. Some pressure canners have a safety feature that prevents the lid from being removed while it is still pressurized, but I wouldn't rely on this. I say, "use your own head."

Sealing Ring

If your canner has a lid that fastens down by turning it, then it should have a rubber sealing ring. If it is dried up and stiff or if it is sticky, then it should be replaced.