Cook Surface Precautions for Home Canning
Can I pressure can using a camp cooker?
Here’s what ALL new Presto and National Canners say in their instruction manuals:
“Caution: Do not use pressure canner on an outdoor LP gas burner or gas range over 12,000 BTU’s.”
When contacted, their customer service also does not recommend using any (new or old) model Pressure Canners on LP gas burners over 12000 BTU’s.
The main reason is that the high heat can damage pressure canners, especially the newer and thinner aluminum versions. The damage can range from simple warping to severe warping (where the lid might detach) to fusing of the aluminum canner to the LP stove. In all cases the damage will make the canner non-functional.
The other potential damage results from boiling out the canning water too quickly. If a pressure canner goes dry, it almost certainly will warp. We here at USU know this for a fact during some of our research canning runs. A pressure canner ran dry for only a few minutes and the bottom warped so that it was no longer usable.
Can I can on my smooth cook top?
Some ceramic or glass cook-top manufacturers:
- advise against canning on their tops
- make no such disclaimers; or
- stipulate that the canner diameter be within a certain diameter of their burner.
Be sure and read your manufacturer’s guide to determine what recommendations they are making. If you no longer have their guide, contact them via their toll-free consumer numbers.
What can happen?
Some older glass-tops broke under the weight of the canner (water, jars and food). There can also be damage to the cook-top from excessive heat reflected around the canner, especially if the canner is larger than the burner circle. The damage can range from discoloration light colored tops to cracking of the glass tops. Note that dragging any pot across a glass top can cause scratching.
Many of these cook-tops have automatic cut-offs on their burners when heat gets excessive. If that option is built in, and the burner under a canner shuts off during the process time, then the product will be under-processed and will be a risk for botulism food poisoning.
If your manufacturer only recommends a pot of equal or smaller diameter to the burner, you can create a boiling water canner from any flat bottomed stock pot. The pot used as a boiling water canner must also be large enough to have lots of water boiling freely around the jars, and at least 1 inch over the tops of jars. Some newer pressure canners have a special bottom that was created to accommodate burner diameters.
- Check with the manufacturer of your smooth glass or ceramic top stove for their recommendations on canning.
- Use flat bottomed canners if allowed to can on them.
- Keep the canner as close in diameter to the burner as possible.