Whether your kitchen has all the modern conveniences or you live off the grid, for canning purposes, some heat sources work better than others. When I bought the cooktop I use now, most of the manufacturers I contacted didn’t furnish information about their product’s suitability for canning. With today’s focus on home food production, the scene has changed dramatically. Now most manufacturers offer recommendations concerning the use of their units for canning. Other sources, like a portable electric burner, can come in handy as an auxiliary heat source.
The big issue for many home canners is whether or not canning may be done on a ceramic glass cooktop. Some manufacturers recommend not canning at all on this type of top. Ignoring that recommendation may void the warranty. Since smooth cooktops vary in their stability for canning, the most sensible plan is to follow the manufacturer’s advice.
One possible issue with smooth cooktops is a canner’s weight. Older glass cooktops were relatively thin and likely to crack under the weight of a full canner. Some newer glass cooktops are reinforced or otherwise thick enough to hold up under the weight.
Another issue occurs if the canner bottom is ridged or concave, rather than flat. On a smooth cooktop, a canner with a non-flat bottom won’t efficiently and evenly distribute heat. As a result, the canner may fail to maintain a full boil (in a water bath canner) or full steam (in a steam canner) sufficient to surround the jars.
Yet another issue is the intense heat reflecting back from the canner onto the cooktop surface, which may damage the top. To avoid this problem, manufacturers specify a maximum recommended canner diameter in relation to burner size, which may be as little as one inch. The diameter of a typical canner is about 12 inches.
Depending on the size of your cooktop’s burners, and on the manufacturer’s recommendation, finding a canner of suitable size may then be an issue. A pot that is too small for proper canning may come to a boil too rapidly, reducing the total amount of processing time and causing the jars to be under-processed, rendering the food in them unsafe to eat.
Using a canner that is larger than the recommended diameter reflects excessive heat back onto the cooktop, possibly resulting in damage to the burner, a cracked glass surface, or the metal canner fusing to the cooktop. To prevent the smooth top from overheating, many glass cooktops have a protective feature that automatically turns off a burner if it gets too hot. When that happens during a canning session, the food will be under-processed and unsafe. The automatic heat cut-off especially is a problem with a pressure canner, which operates at a higher temperature than a water bath or steam canner. If your smooth cooktop has an automatic cut-off, it may not be at all suitable for canning.
A smooth cooktop is either radiant heat or induction. A radiant top has electric heating elements beneath the glass surface, functioning much the same as a regular electric cooktop with coil burners. Some radiant cooktops have burners of different sizes. Others detect the size of your canner and automatically adjust the burner size accordingly.
An induction cooktop has copper elements beneath the glass that generate an electromagnetic field that transmits energy to the canner, causing it to heat up. Some induction tops automatically adjust energy output according to the canner’s diameter. For an induction cooktop to work, the canner must be magnetic, meaning a magnet will stick to it. Stainless steel canners are magnetic; aluminum canners are not. Therefore, you cannot use an aluminum canner on an induction cooktop.
Some people attempt to overcome this problem by putting an induction interface disk between the aluminum canner and the cooktop. The flat magnetic disk conducts heat from the induction cooktop to the canner, making the cooktop less efficient. It can also overheat the cooktop.
An enameled canner — constructed of porcelain enamel coated steel — poses a unique issue for induction cooktops. Although the steel is magnetic, the enamel coating can overheat, melt, and ruin the cooktop.
Even using a recommended type canner on a smooth cooktop that is rated for canning, sliding a full and heavy canner across the top may scratch the glass surface. And, of course, you want to be careful not to drop the canner onto the surface. If you can on a smooth cooktop, the best approach is to place the canner on the cooktop before filling it and heating it, then leave it in place until the processed jars are removed from the canner — thus minimizing the potential of damaging your smooth ceramic glass cooktop.
When my husband and I moved to our Tennessee farm, the kitchen was equipped with an electric range on which we canned for many years. One of the things I didn’t like about it was that the coil took a long time to heat up and then took a long time to cool down. Further, the coil that I used for canning had to be replaced so frequently I took to keeping a spare on hand.
An electric coil that is suitable for canning should be no more than four inches smaller than the diameter of the canner. For heating a typical 12-inch diameter canner, the coil must be at least eight inches in diameter.
If the coils on your electric cooktop are too small for your canner, you might opt to use a portable electric burner instead of an alternate food preservation method. Some home canners use such portable electric burners for many other reasons: their smooth cooktop is not rated for canning; they want to operate the canner where it won’t heat up the kitchen; their garden yields produce faster than the kitchen’s cooktop alone has the capacity to process.
A portable electric burner used for canning should pull at least 1500 watts. And, as with any electric coil, the portable electric burner should be no more than four inches in diameter less than the canner bottom, meaning the canner extends no more than two inches beyond the burner all around.
If you use the portable electric burner on your countertop, to prevent heat damage to the counter the unit must allow for sufficient air circulation underneath. The unit must also be stable enough to accommodate a heavy canner while remaining level. A restaurant supplier would be a good source for a quality portable electric burner that’s sturdy enough for canning and made of heat-resistant cast iron and stainless steel.
From online discussion groups, you can learn which currently available portable electric burners people are successfully using with specific types of canners. Options include not only portable electric coils but also portable induction burners. Yet another option is an all-in-one electric appliance.
When my farm kitchen was remodeled I opted for a propane cooktop as being the most suitable type for the considerable amount of canning I do. In terms of heat regulation, it is much more responsive than the old electric range. Also, the sturdy iron protective grate over the burners supports a canner of any size, and I can slide a canner along the grate without causing damage to the cooktop or the pot. Another big plus is that, given the unpredictability of power outages, gas is more reliable than electricity.
The four burners on my cooktop are rated for 5,000, 9,000, 11,000, and 12,000 BTU respectively. For canning, I most often use the 12,000 BTU burner. Gas burners rated higher than 12,000 BTU are not recommended for use with low-cost canners made of thin aluminum. Higher heat could warp and ruin a thin-wall aluminum canner.
Portable gas stoves are popular with canners who live off the grid, don’t want to heat up the kitchen on an already hot summer day, or have smooth cooktops not rated for canning. For outdoor canning, the unit must be operated in a protected area where the temperature won’t fluctuate because of breezes. Some people set up a wind break. Others use a covered porch or open garage that offers wind protection while providing plenty of necessary ventilation.
Some authorities discourage canning on outdoor gas stoves because of the danger of tipping and spills, especially where frisky pets and boisterous children might be involved. It goes without saying that kids and pets should play at a distance.
A portable gas unit used for canning must be stable enough to accommodate a heavy canning pot without tipping over. Both tabletop and stand-alone units have been successfully used by home canners. As with portable electric burners, the selection and use of outdoor gas stoves for successful canning are discussed in detail by many online groups.
One of the latest innovations in canning appliances is the Ball FreshTech electric water bath canner and multi-cooker, which may be used to process 7 one-quart jars, eight pints, or 12 half-pints at a time. Ball claims this appliance is 20 percent more efficient in energy use than canning on an average electric stove. As a multi-cooker, the unit may also be used as a stockpot or a vegetable steamer.
For canning, this appliance works essentially the same as a stove top water bath canner, with a couple of exceptions. One is that it comes with a diffuser rack that is placed on top of the jars during processing. The rack is designed to diffuse boiling evenly throughout the pot and reduce water splatter. Another difference is that, when the processing time is up and the appliance is turned off, after a cooling period of five minutes, the water is drained from the canner (through a built-in spigot) before the processed jars are removed.
The Ball water bath canner may be used to process any reliable high-acid food recipe. Approved food preservation examples and recipes may be found online at the National Center for Home Food Preservation (nchfp.uga.edu/), in the 2015 edition of USDA Complete Guide to Home Canning (nchfp.uga.edu/publications/publications_usda.html), and in the 2015 edition of Ball Blue Book Guide to Preserving.
Ball produces a smaller electric home canner that holds 3 one-quart jars, five pints, or six half-pints. It has a digital touch pad with easy-to-use food category buttons for, respectively, jams and jellies, fruits, tomatoes, salsas, pickles, and sauces. This appliance does not double as a cooker but is designed only for canning specific recipes provided with the unit or published by Ball Canning under the “auto canner” category on their website.
Similar-looking appliances are widely advertised as pressure cookers that double as pressure canners. Some even have buttons labeled “canning” or “steam canning.” Pressure cooking is not at all the same as pressure canning. For many reasons, using an electric pressure cooker as a canner does not ensure safe processing of food sealed and stored in jars. Why take the chance?
What heat sources have you found to be the most reliable when you’re canning? Let us know in the comments below.