How to Can Plain Tomato Sauce in Canada (Bernardin Method)

If how to can tomatoes is the September gateway recipe, tomato sauce is the gateway recipe’s smarter, denser sibling. Same tomatoes, same lemon juice rule, but you strain out skins and seeds and reduce the pulp down to something that drops off a spoon. The result: jars of plain tomato sauce that go into chili, soup, pasta, shakshuka, braises — anywhere “1 can of tomato sauce” appears in a recipe all winter.

This is plain tomato sauce only. The moment you add onions, garlic, peppers, oil or meat, the recipe is no longer water-bath safe — that’s the pH rule from the spaghetti sauce article. Pasta sauce with stuff in it = pressure canning. Plain tomato sauce = water-bath canning with lemon juice. (Optional salt and dried herbs in the jar are the one exception, and they are Bernardin’s, not ours — see below.)

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What you’ll end up with

• About 7 × 500 mL jars from 10 kg (22 lb) of paste tomatoes
• A 50% reduction from raw tomato volume to finished sauce
• Smooth texture — no skins, no seeds
• Sauce thick enough to coat a spoon but still pourable
• Shelf-stable for 12 months in a cool, dark place

10 kg sounds like a lot. A single bushel from a tomato U-pick farm is ~25 kg ($30–40 in late August / September), so think of one canning session as a third of a bushel. Two sessions and your pantry is set.

Equipment you’ll need

The strainer is the part that makes this project realistic. Without it you’re scooping seeds and peeling skins one tomato at a time.

• A food strainer or mill — the single biggest time-saver. Options below.
• A boiling water bath canner (any tall stockpot with a rack) — which canner to buy, and when a stockpot is genuinely enough
• 7 × 500 mL Bernardin jars (or 3–4 × 1 L jars) + fresh SNAP lids + bands
• Standard canning kit — jar lifter, headspace tool, funnel, ladle
• A wide heavy-bottomed pot (8 L+) for cooking the sauce down
• Bottled lemon juice — about 120 mL per batch
• A large bowl of ice water for the peel-loosening dip (if not using a Victorio-style strainer)

Three strainer paths, from fastest to slowest

Tool	Type	Blanching needed?	Time for 10 kg	Cost
Victorio Food Strainer (or KitchenAid attachment)	Mechanical, hand-cranked or motor-driven	No — eats raw tomatoes	30 min	$80–250
Manual food mill (OXO, Mouli)	Hand-cranked, cone-shaped	Yes — blanch + peel first	60 min	$40–80
Fine-mesh sieve + wooden spoon	Manual, no moving parts	Yes — blanch + peel first	2+ hours	$15–25

If you can plan ahead and you’re going to can sauce more than one season, the Victorio is worth it. If a manual mill is the right size of purchase instead, which food mill to buy compares them. Expect the $80–250 band above at the Canadian Tire / Lee Valley / Bass Pro tier. Pays itself off in time saved during a single tomato season.

Choose the right tomatoes

• Paste / Roma varieties are the right call: San Marzano, Amish Paste, Roma, Plum. Less juice, more pulp, less reduction needed.
• Beefsteak and slicing tomatoes work but yield 30–40% less sauce per kilo. Use them if that’s what you have, just plan on a longer simmer.
• Cherry and grape tomatoes — skip. Tiny, lots of seeds, terrible yield-to-effort ratio.
• Bruised or split is fine if you cut out the bad spots. Mouldy is not — discard those.

For 10 kg of paste tomatoes you get about 3–4 L of sauce after reduction → ~7 × 500 mL jars (growing tomatoes in Canada).

The method

Step 1: Heat the canner

Fill your water-bath canner with enough water to cover the jars by 2.5 cm. Bring to a simmer. Warm your empty Bernardin jars in the simmering water so they’re hot when you fill them.

Step 2: Process the tomatoes

With a Victorio-style strainer:

1. Wash tomatoes, cut into quarters
2. Feed them into the strainer hopper, crank the handle
3. Pulp drips into one bowl, skins-and-seeds extrude out the other end
4. Done in 20–30 minutes for 10 kg

With a manual food mill:

1. Score each tomato with a shallow X on the bottom
2. Blanch in batches: drop into boiling water for 30–60 seconds until skins crack
3. Plunge into ice water
4. Slip off skins
5. Quarter and core, removing any bruised flesh
6. Run the cores-and-flesh through the food mill into your cooking pot
7. Compost the skins

Either way, you end up with about 5 L of raw, smooth tomato pulp.

Step 3: Reduce the sauce

Bernardin does this at a boil, not a simmer, and builds the pot up in stages rather than tipping it all in at once. Return 4 cups (1 L) of the sieved pulp to a wide, deep pot and bring it to a vigorous boil, then add the rest 1 cup (250 mL) at a time, keeping a steady boil throughout. Once it’s all in, boil gently and stir occasionally until it reaches the consistency you want.

How far you reduce is the recipe’s one real decision, and Bernardin gives two answers:

• Reduce by one-third — thin sauce. Pourable, closer to passata.
• Reduce by one-half — thick sauce. Coats a spoon.

That choice is also what your shopping list depends on: Bernardin reckons 35 lb (15.8 kg) of tomatoes fills seven 1 L jars of thin sauce, and 46 lb (20.8 kg) fills seven 1 L jars of thick. A third more fruit for the same seven jars, because you’re boiling more water off.

Stir every 10–15 minutes to stop it scorching, and don’t add anything else — see the note on herbs below for the one exception Bernardin allows.

Step 4: Acidify each jar

This is the food-safety step that makes plain tomato sauce water-bath safe. Every jar, every time:

• 500 mL jar: 1 tbsp bottled lemon juice
• 1 L jar: 2 tbsp bottled lemon juice

Alternative: ¼ tsp citric acid per 500 mL or ½ tsp per 1 L. Bernardin-approved either way.

Add the lemon juice directly to each empty hot jar before filling. Don’t try to add it to the cooking pot — the per-jar measurement is what the tested process was validated against.

Bottled lemon juice only. Fresh lemon juice varies in acidity from lemon to lemon and is not safe here.

Optional, in the jar, at the same time: salt — ½ tsp per 500 mL, 1 tsp per 1 L — and dried herbs to taste.

Dried herbs are worth calling out, because this page used to say no herbs at all. Bernardin’s own tomato sauce recipe lists dried herbs as an optional jar addition, and we were being stricter than the authority we cite. The distinction that actually matters is not herb versus no herb — it is dried versus fresh, and low-acid versus not. A pinch of dried oregano adds essentially no mass and no water. A chopped onion, a clove of garlic, a diced pepper, a splash of oil or any meat is a low-acid ingredient in volume, and that is what takes the jar out of water-bath range entirely.

Step 5: Fill the jars

Ladle hot sauce into each acidified jar through a wide-mouth funnel. Leave 1 cm (½ inch) headspace.

This page previously said 2 cm and called it “Bernardin’s standard for tomato products.” There is no such standard — Bernardin’s tomato sauce, crushed tomatoes and whole tomatoes recipes all finish at 1 cm. Too much headspace doesn’t under-process the food, but it leaves air the process can’t drive out, and that is a seal-failure mode.

Step 6: Debubble and wipe

Run a non-metallic spatula or chopstick around the inside of each jar to release trapped air. Re-check headspace; top up if needed. Wipe each rim clean with a damp cloth — sticky residue kills the seal.

Step 7: Apply lids and process

Centre a fresh SNAP lid on each jar, apply a band fingertip-tight. Lower jars into the canner with the jar lifter; ensure they’re covered by 2.5 cm of water.

Bernardin’s Tomato Sauce recipe gives 35 minutes for a 500 mL jar and 40 minutes for a 1 L jar, at altitudes up to 305 m. Start timing when the water returns to a full rolling boil, and add the boiling-water increment for your band above 305 m — the table is at the foot of this page, and our altitude-adjustments guide explains it. Verify against your Bernardin edition before you start.

A note if you go looking at their page yourself: the summary box at the top reads 60 Minutes, which matches neither figure in their own directions. Read the directions, not the box.

Step 8: Cool and check seals

Turn off the heat, wait 5 minutes, then lift the jars out without tilting them and stand them upright on a towel-lined counter. Leave undisturbed 24 hours, and do not retighten the bands. Some lids ping as they seal and some stay silent; the sound proves nothing in either direction. After cooling, press the centre of each lid — one that flexes or clicks has not sealed. A lid that stays firm shows no defect, which is not the same as clearing the jar.

If a jar didn’t seal, the 24-hour rule applies.

Storage and use

• Pantry (unopened): 12 months best quality — Bernardin’s guidance for home-canned food
• Opened: refrigerate, use within a week
• Date every jar with a Sharpie on the lid

What to do with plain tomato sauce:

• Pasta — heat the sauce, add fresh garlic and basil at the end, toss with pasta
• Chili base — start with sauce, brown beef, add beans and spices
• Shakshuka — sauce + onions + peppers (in the pan, not the jar) + poached eggs
• Soup — tomato soup with sauce + cream + basil
• Braises — add to short ribs, lamb shanks, chicken cacciatore
• Pizza sauce — reduce further with herbs in the pan when you’re making pizza

Common questions

”Can I just use canned grocery-store tomatoes for sauce?”

Yes for the recipe (better flavour for “homemade” sauce in winter from grocery cans than from sad winter tomatoes). No for the canning project — there’s no point canning already-canned tomatoes. The whole point is preserving the fresh August/September harvest.

”My sauce separated in the jar — water on top, pulp on the bottom”

Normal. Stir when you open. Combined with a bulging lid, foam, or off smell, discard the jar.

”Is the lemon juice flavour going to come through?”

No. The 1 tbsp per 500 mL is below the taste threshold once the sauce is finished. You won’t notice it. The pH change matters; the flavour change is invisible.

”What if I want to add basil?”

Add fresh basil when you open and serve the jar, not before canning. The optional jar addition Bernardin’s recipe names is dried herbs; they do not name a fresh one, and we are not going to clear an ingredient their tested recipe does not list. Fresh basil also goes grey-brown during processing and adds nothing to the finished jar. Save it for the pan.

Corrected 19 September 2026: this answer used to say that fresh herbs in the jar before canning “won’t kill you”, and gave a reason of our own for why basil was different from onion. That was a clearance we invented, and it contradicted this page’s own line four sections above that the distinction which matters is dried versus fresh. If you have water-bathed a jar of plain sauce with fresh herbs in it, we cannot tell you it is safe and we are not going to try — treat it as a jar made to an untested recipe: refrigerate it and use it, or freeze it, rather than keeping it on a shelf. The dried-herb option is Bernardin’s and is unchanged.

When to make this

Late August through late September in Canada. Tomato U-pick farms peak around Labour Day; grocery store tomato prices drop in early September. Plan two canning sessions: one for crushed/whole tomatoes (the parent recipe) and one for sauce. The two together stock a household for the year.

Next steps

• How to can tomatoes (crushed and whole) — the chunky parent recipe.
• The pH rule — why you can’t add onions or meat to canned sauce.
• Salsa — the structured exception to that rule.
• How to dehydrate tomatoes in Canada — concentrated sun-dried-style tomatoes from the same paste varieties.
• Water-bath canning pillar — full method context.
• Canning altitude adjustments — for the minute math.