- 1 Two types of glass stove tops
- 2 Canning on Glass Stove Tops
- 2.1 The issue from point of view of the stove top can be:
- 2.2 The issue from point of view of the canning pot can be:
- 2.3 Steam canning on glass top stoves
- 2.4 Water-bath canning questions in relation to glass stove tops
- 2.5 Pressure canning questions in relation to glass stove tops
- 2.6 Presto Canners
- 2.7 Special Notes about Induction Canning
- 3 Utah State’s advice on about canning on glass-top stoves
- 4 Ball’s advice on canning on glass tops
- 5 Further Reading
Two types of glass stove tops
There are two types of glass (aka ceramic aka smooth) stove tops:
1. Regular smooth tops, also known as radiant
In wells below the smooth top, there are electric heating elements. These elements radiate heat which passes up through the glass top to the surface on top, and then via the surface to the pot on top of that burner area.
The heating elements cycle themselves off and on as necessary to maintain the requested heat so that the heat does not go higher than requested (via the burner dial.)
2. Induction stove tops
In wells below the smooth top, there are electric elements. They generate a magnetic field which does not radiate heat. The magnetic energy transfers up through the glass top to the pot on top of the burner area. The magnetic waves “excite” the metal in the pot, causing the metal to get hot. The metal in turn then heats up the food.
Induction is considered more energy efficient as it skips the step of having to heat a burner on top; and just heats the cookware directly.
The induction heating elements DO NOT cycle themselves off and on. They emit a steady constant precise power, which some say is so precise that you can make it steady and gentle enough even to melt chocolate without the need of a double boiler.
If a magnet will stick to the bottom of a canner pot, then it will work with induction. If it won’t, then the canner won’t work with your stove top. (What the pot bottom needs is some iron content in its metal.) For that reason, induction won’t work with aluminum, glass or ceramic cookware, etc.
Induction burners are more expensive.
Canning on Glass Stove Tops
Both types of glass tops, regular and induction, can in theory be fine for canning on.
The issue from point of view of the stove top can be:
- because the strong, heat-resistant glass is only in the burner areas, it’s important not to transfer too much intense heat out past the burner area where the heat might damage more frail glass;
- scratching the stove-top if you drag canners across it;
The issue from point of view of the canning pot can be:
- a smooth bottom to ensure good heat transfer up into the pot;
- steady reliable heat.
Steam canning on glass top stoves
If you have a glass top / smooth top / induction stove and want to steam can, as of summer 2016 there is only one model of steam canner on the market currently certified for that. That is the Victorio Stainless Steel Multi-use Canner .
Water-bath canning questions in relation to glass stove tops
- The water in water-bath canning is supposed to come to a boil more quickly on induction burners — some people have wondered if this shorter “coming to a boil” time is a problem;
- The traditional grey or blue Graniteware canners have very large bases and would extend out onto the non-tempered glass;
- These traditional Graniteware canners usually have ridged bottoms.
- The answer to 1 appears to be — with water bath-canning, it’s the processing time and the cool-down time that are important. I’m not yet aware of any studies showing the sterilizing value of coming up to heat being counted in water-bath canning because processing time only starts when a full boil is reached;
- The pot base should extend out past the burner by no more than 2 – 3 cm (1 inch) on all sides;
- The canner needs to have a flat, non-ridged bottom. The large Graniteware water bath canners traditionally had ridged bottoms designed to deliberately limit contact with a burner to prevent warping of the bottom of the pot.
Therefore the old-fashioned, Graniteware water bath canners might not work.
Apparently some users have reported that their induction stove manufacturers have even advised that the enamel on the Graniteware pot might melt onto the stove top.
While the metal used for Graniteware water bath canners has some iron in it, the metal is very thin, and might not be enough “metal” to engage an induction burner’s safety threshold (apparently, this is a safety feature built-in to stop the burner from heating up a ring on your hand passing over an element, or heating up a metal utensil placed somewhere off to the side.)
You can get conversion disks for induction burners, though: the disks heat up, thus enabling any type of pot to work on the burner. (If the disk raised a broad bottom off the stove surface, that could possibly make the broader bottom safe for the stove top as well.)
FYI the Ball stainless steel water bath canner, even though it has an aluminum core, is 18/20 gauge stainless steel, so it will work on induction. It has a flat bottom, so that it will work on induction and glass stove tops. And , it is not as wide as the old Graniteware ones that extend way out past the burner. Ball says,”Its flat stainless steel bottom allows it to sit and work perfectly on glass top stoves….Compatible with all variety of stovetops.” 1
Pressure canning questions in relation to glass stove tops
- Some have wondered if the cycling of the burners on a regular glass stove top (aka radiant) would affect the temperature inside the pressure canner;
- If the base of the canner were larger than the burner and extended out past the burner onto the plain stove top, there was worry that heat transference from the base of the canner would damage other parts of the stove top;
- Some question the weight load, especially when a large pressure canner is double-decked.
1. Induction burners don’t cycle. With Radiant Heat (Regular Glass Top Stoves), the expressed worry by the experts is actually something quiet different: it’s about the burner actually turning itself right off.
The National Center for Home Food Preservation (NCHFP) writes, “Many of these cooktops 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 underprocessed and cannot be salvaged as a canned food.” 2 .
Note that the NCHFP is talking about a safety, emergency cut-off when heat becomes excessive that turns the burner right, completely off. This is completely different from the normal operation of the radiant heat burner, cycling off and on as required to maintain the current heat so that it doesn’t go higher than you requested via the stove dial. The burner is not shutting off. There is no pressure being lost, the requested heat is being maintained — as you can tell from your dial-gauge or weighted gauge. Either type of gauge will let you know if the burner has done an emergency shut off, because you will see / hear the corresponding loss in pressure.
So you do not need to worry about the normal operation of cycling of the radiant burners. And, if you have regulated your heat down to just enough heat to maintain the proper pressure on your pressure canner, as you need to do anyway for a successful canning session, you should never experience the emergency shut-off, either.
2. In both cases, for both glass and induction, the canner needs to have a flat, non-ridged bottom. The pot base should extend out past the burner by no more than 2 – 3 cm (1 inch) on all sides.
3. Check with your stove manufacturer to see what the maximum weight load is that they support for the stove top. Some stove manuals may advise “max 50 lbs weight load” on the burners. It’s best to check your model manual and see what it says, or if it says nothing, contact the manufacturer. For instant, the Maytag “Gemini Smoothtop Double Oven Range” manual says canning is fine on the stovetop, and even has a section dedicated to home canning usage of the burners.
Presto is the only manufacturer (as of spring 2015) saying that their pressure canner models currently in production are safe for glass stove tops.
Note that while Presto supports double-decking of pint jars in its 23 quart canner for pressure canning, it does not support the same for water bath canning. They don’t say why; one could speculate that it might be a weight issue impinging upon their claim to support glass stove tops.
Read more about Presto Canners.
Special Notes about Induction Canning
- You can get conversion disks for induction burners, which allow aluminum canning pots such as the Presto above to be used on the burners;
- Some people worry that with induction, the magnetic waves will reach up to the top of the jars in the canner, excite the metal lids and bands, and interfere with a seal happening. We have seen no research on this.
Utah State’s advice on about canning on glass-top stoves
Utah State says the following about canning on smooth, glass-top stoves: 3
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 manufacturers guide to determine what recommendations they are making. If you no longer have their guide, contact them via their toll-free consumer numbers.
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.
Ball’s advice on canning on glass tops
Piper, Jessica. Canning with a Glass Top Stove. Ball Corporation. May 2014.
Botzek-Linn, Deb. Canning On a Smooth or Ceramic Cooktop. University of Minnesota Extension Service. 2014. (Link valid as of May 2015)
National Center for Home Food Preservation. Canning on Smooth Cooktops . (Link valid as of May 2015)
Ball Product page for ‘Collection Elite® Stainless Steel Waterbath Canner’. Accessed March 2015 at http://www.freshpreserving.com/products/collection-elite/stainless-steel-waterbath-canner ↩
National Center for Home Food Preservation. Canning on Smooth Cooktops: Accessed March 2015 at http://nchfp.uga.edu/publications/nchfp/factsheets/smoothtops.html ↩
Nummer, Brian A. Cook Surface Precautions for Home Canning. Utah State Cooperative Extension. FN/Food Preservation/2009-03. September 2009. Accessed March 2015 at http://extension.usu.edu/files/publications/publication/FN_Food_Peservation_2009-03.pdf ↩