Water-Bath Canning Without a Canner
Yes, you can water-bath can without buying a purpose-made canner, and this is Bernardin's own tip rather than a workaround: turn any large, deep pot into a boiling water canner and tie screw bands together to make a rack. Bernardin describes a boiling water canner as a large deep pot with a tight fitting lid and a rack to lift jars off direct heat, deep enough to cover the jars with 3 to 5 centimetres of water. Three things have to be true of your pot. It must be deep enough that at least 2.5 centimetres of water covers the jar tops with room left over for a rolling boil, it needs a lid, and the jars must never sit on the bare bottom of the pot. What you cannot substitute is a pressure canner. Only high-acid foods — jams, fruits, tomatoes with added acid, and pickles including relish and chutney — can be processed in boiling water at all. Low-acid vegetables, meat, poultry and seafood need 116 degrees Celsius and a stockpot cannot reach it.
Yes — and it is Bernardin’s own tip, not a workaround. From their home canning FAQ:
Tip: Turn any large, deep pot into a boiling water canner and tie screw bands together to make a rack.
That sentence sits under their description of what a canner actually is, which is the whole answer:
A boiling water canner is a large deep pot with a tight fitting lid and a rack to lift jars off direct heat. The pot must be deep enough to cover jars with 1 to 2 inches (3-5 cm) water.
Three things have to be true of your pot
Nothing else about it matters — not the brand, not the metal, not whether the word “canner” appears on it.
| What it needs | Why | |
|---|---|---|
| Depth | A pot 7.5 cm (3 in) taller than your jars — 2.5 cm of water over the lids plus 5 cm of air above it | The jars must stay fully submerged for the whole process time, and the air space is what keeps a rolling boil inside the pot |
| A rack | Anything keeping jars off the bare bottom, with water able to move underneath | Direct contact with the element cracks jars and leaves cold spots |
| A lid | One that fits reasonably flat | It is what holds a full boil for the whole time without losing the water |
Measure the depth with a jar, not by eye. Stand one empty jar of the size you plan to use on the rack, fill until the water sits 2.5 cm above its top, and look at how much pot wall is left. About 5 cm of clearance above the waterline is what stops a rolling boil going over the side — and that figure is Bernardin’s, not ours: p.7 gives 2 inches (5 cm) of air space, for exactly that reason. If the water is near the rim, that pot is too shallow for that jar size — it may still be fine for 250 mL jars, which is worth checking before you give up on it.
Making the rack
The jars cannot sit on the bottom of the pot. That is the only real gap between a stockpot and a canner, and Bernardin’s answer costs nothing:
- Screw bands tied together. Their own suggestion. Use bands you are not processing with, laid flat in a single layer and tied with kitchen string so they cannot drift apart.
- A round cake-cooling rack that drops into the pot.
- A folded tea towel, in a pinch — it works, but it shifts and it slows water circulation underneath, so it is the weakest of the three.
What none of these fixes is a pot with no lid, or a pot too shallow. Depth is the one thing you cannot improvise.
What this does not let you do
This is the part that matters more than the pot.
Only high-acid food can be processed in boiling water at all — a purpose-made canner has exactly the same limit. Bernardin’s list is specific:
Only high acid foods — jams, fruits, tomatoes with added acid, pickles (including relish, chutney) — can be processed safely in a boiling water canner.
Everything else — vegetables, meat, poultry, seafood, soup, stock, plain tomato sauce with no added acid — needs a pressure canner, because it needs 116 °C, which Québec names as the safe temperature only a pressure canner can reach. Water boils at 100 °C in an open pot and stays there. Boiling it for three hours instead of one changes nothing at all; the temperature is set by physics, not by patience.
There is no stockpot version of a pressure canner (Presto against All American). That is the honest end of the sentence: pressure canning requires the equipment.
Tomatoes are the seasonal trap here. They go in a boiling-water canner only with added acid — bottled lemon juice or citric acid in every jar, every time. How to can tomatoes has the amounts, and forgot the lemon juice covers what to do if they are already on the shelf without it.
What you still cannot substitute for the pot
A stockpot works because it does the same thing a canner does: holds jars under boiling water for a known time. The things that fail are the ones that change the method, not the container. Canning methods that are not safe covers the full list Bernardin names — but the four that come up when someone has no canner are worth naming here:
- The oven. Bernardin: “Not only is it unsafe, oven-canning can be extremely hazardous.” Jars break, and dry heat does not penetrate the food.
- A steam canner. Shallow pan, unpressurised steam, uneven temperature, and no established processing times.
- Open-kettle. Hot food straight into jars, lid on, hope for the ping. The jars are never heated to the temperature that matters.
- A slow cooker or multicooker. Bernardin’s line is that a boiling water canner and a pressure canner are the only currently approved methods for safe home canning.
Running it, in the pot you have
Same process as any water-bath batch, and the water-bath canning pillar has the full version. What differs with an improvised setup:
- Put the rack in first, before any water, and check it sits flat.
- Heat the jars in the same pot. Bernardin’s convention is to hold washed jars at 82 °C until you fill them. Do not preheat the lids — they advise against it, because the sealing compound performs better at room temperature.
- Lower the filled jars in so they do not touch each other or tip. Tongs work; a jar lifter works better and is the one tool genuinely worth its price.
- Check the water covers the tops by at least 2.5 cm before you put the lid on. Add boiling water, not cold, if it is short.
- Start timing when the water reaches a full rolling boil, not when the jars go in.
- Adjust for your altitude — the table below is Bernardin’s, and it applies to any pot.
- Turn off the heat, take the lid off, and wait 5 minutes before lifting the jars out. Then leave them undisturbed 24 hours and do not retighten the bands.
When a real canner starts earning its money
Not on safety — on batch size and your evening.
A 21–22 litre canner takes seven 1 L jars in one load — the Complete Book puts the standard 21 quart (21 L) canner at exactly that (p.7) — comes with a rack that fits, and is deep enough without measuring anything. On a September afternoon with 20 lb of tomatoes on the counter, doing that in three loads of a stockpot is the difference between one evening and two.
If you put up a few jars of jam a summer, the pot in your cupboard is genuinely enough. Our water-bath canner guide is there for when the batch size, not the safety, is what is costing you.
Related
- Canning methods that are not safe — the eight Bernardin names, and why the oven is not an option
- Water-bath canning — the full method, start to finish
- Canning equipment checklist — what is genuinely required versus nice to have
- How to can tomatoes — the added acid a boiling-water batch depends on
- What to do with 20 pounds of tomatoes — the September problem this page usually arrives with
Altitude adjustment
Process times in a boiling-water canner are written for altitudes up to 305 m. Above that, water boils below 100 °C and the time printed in the recipe is no longer enough. Find your elevation, then add the minutes Bernardin publishes for that band.
| Elevation (m) | Elevation (ft) | Add to processing time |
|---|---|---|
| 0 – 305 | 0 – 1,000 | None — use the recipe time as written |
| 306 – 915 | 1,001 – 3,000 | +5 minutes |
| 916 – 1,830 | 3,001 – 6,000 | +10 minutes |
| 1,831 – 2,440 | 6,001 – 8,000 | +15 minutes |
| 2,441 – 3,050 | 8,000 – 10,000 | +20 minutes |
On the line between two bands, round up to the higher one. Slightly over-processing is safe; under-processing is not.
Bernardin’s published tables stop at 3,050 m.
Find your Canadian city · Full altitude guide
Figures from Bernardin, “How do I can at a high altitude?” (bernardin.ca). Confirm against your own Bernardin edition before you start — a book edition and the website can differ.
Frequently asked questions
Is a stockpot really as safe as a real canner?
For the process itself, yes — provided it meets the three conditions. What a boiling water canner does is hold the filled jars fully under boiling water, off the direct heat of the element, for the recipe's time. Bernardin describes it as a large deep pot with a tight fitting lid and a rack, and their own tip is to turn any large, deep pot into one. Nothing about the pot's brand affects the process. What a purpose-made canner buys you is a rack that already fits, a lid that already fits, and enough depth for tall jars without measuring.
What can I use as a rack?
Bernardin's suggestion is to tie screw bands together to make one, which costs nothing if you already have bands. A round cake-cooling rack that fits the pot works, as does a folded tea towel in a pinch, though a towel can shift and lets less water circulate. The requirement is only that the jars do not sit on the bare bottom of the pot and that water can move underneath them. Direct contact with the element is what cracks jars.
How do I know whether my pot is deep enough?
Measure it with a jar rather than by eye. Stand one empty jar of the size you plan to use on your rack inside the pot, and fill with water until it sits 2.5 cm above the jar top. If there are still about 5 cm of pot wall above the waterline, you have room for a rolling boil without it going over — that 5 cm is Bernardin's own air-space figure (p.7), not a rule of thumb of ours. If the water is near the rim, the pot is too shallow for that jar size — but it may be fine for 250 mL jars.
Can I do vegetables or meat in a stockpot if I boil them longer?
No, and longer does not help. Water boils at 100 °C and no amount of extra time raises it. Québec names 116 °C as the safe temperature only a pressure canner can reach. Bernardin's list of what can be processed in boiling water is specific: jams, fruits, tomatoes with added acid, and pickles including relish and chutney. Low-acid vegetables, meat, poultry and seafood are pressure-canning foods whatever pot you own.
Do I still need to sterilise the jars?
Jars are heated in water, and Bernardin is emphatic that heating jars in water is the only way to safely sterilise jars and heat process high-acid food. Their convention across recipes is to hold washed jars at 82 °C until you fill them, which the same pot can do while it comes up to the boil. Do not preheat the lids — Bernardin advises against it, because the sealing compound performs better at room temperature.
My pot has no lid. Does that matter?
Yes. Bernardin's description of a boiling water canner includes a tight fitting lid, and it is not decoration: the lid is what keeps the water at a full boil for the whole processing time without losing volume to steam. A lid from another pot that sits reasonably flat will do. If you are topping up water partway through a long process, the pot is losing heat it should not be losing.
Is there any point buying a real canner, then?
Batch size, mostly. A 21–22 litre canner takes seven 1 L jars at once — that is what the *Complete Book* says the standard 21 quart (21 L) canner holds (p.7) — which matters on a day with 20 lb of tomatoes on the counter, and it arrives with a rack and a lid that fit. If you are canning a few jars of jam a year, a stockpot you already own does the same job to the same standard. Buy the canner when the batch size is costing you an evening, not because the stockpot is unsafe.
Sources
- Bernardin Home Canning — Home canning FAQ (https://www.bernardin.ca/en/how-to-can/faq.htm)
- HealthLink BC — Home canning: How to avoid botulism, File #22 (https://www.healthlinkbc.ca/healthlinkbc-files/home-canning-how-avoid-botulism)
- Québec — Home canning: Preparation and prevention (https://www.quebec.ca/en/health/nutrition/food-safety-risk-prevention/food-safety/preparing-cooking-food-safely/home-canning)
- Public Health Ontario — Home canning: literature review, 2014 (https://www.publichealthontario.ca/-/media/documents/h/2014/home-canning.pdf)