How to Can Plums in Canada (Bernardin Method)

Plums are the easiest tree fruit to can in Canada — easier than peaches, because you skip the blanch-and-peel step and, crucially, you skip the acidification math too. A jar of canned prune plums in light syrup is a February dessert waiting to happen: spooned over yogurt, baked into a cake, or eaten straight from the jar.

This guide follows Bernardin’s Plums in Syrup, Complete Book of Home Preserving (ISBN 978-0-7788-0137-5), page 147. The processing times, the headspace, the fruit quantity and the yield below are theirs, and they are stated on this page rather than deferred to your own copy.

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The good news: plums don’t need added acid

This is the one place plums are genuinely simpler than tomatoes. Tomatoes sit right on the pH 4.6 line — the boundary between high-acid (water-bath safe) and low-acid (pressure canning required) — and Québec publishes that an acidifying agent must be added to tomato-based products for the boiling-water method to be safe.

Plums are a high-acid fruit, so canned plums in syrup need no added lemon juice for safety.

We are not going to tell you how far below the line they sit. No source this site holds publishes a pH figure for plums, and Québec’s own high-acid list names raspberries, apples, strawberries and blueberries rather than plums — so the honest claim is the classification, not a margin. Peaches are a third case again: Bernardin publishes no pH for them either, and their two tested peaches-in-syrup recipes add no acid at all, which is why that page declines to settle the question rather than answering it.

That’s the same acidity that makes plum jam set so reliably. You still follow a tested Bernardin recipe for the jar size, headspace, and processing time — but there’s no acid to measure into each jar.

Pick your plums

• Italian prune plums (aka prune plums) — the Canadian canning standard. Freestone, firm, sweet-tart, hold their shape. Best halved.
• Damson — small, tart, excellent for canning and later baking.
• Burbank and Japanese-type plums — juicier and softer; best raw-packed whole-and-pricked.
• Prairie hardy (Pembina, Brookgold) — smaller but can well on the Prairies.

Choose plums that are ripe but still firm. Soft, dead-ripe plums turn to mush in the jar.

Bernardin’s batch for this recipe is 2.7–4.5 kg (6–10 lb) of plums, which fills about 8 × 500 mL jars or 4 × 1 L jars.

What you need

• 2.7–4.5 kg (6–10 lb) ripe but firm plums
• Granulated sugar and water for syrup (see the table)
• Bernardin 500 mL or 1 L jars, fresh SNAP lids, bands
• Standard canning kit — jar lifter, headspace tool, funnel, water-bath canner, ladle (which canner to buy)
• A clean needle or skewer if canning plums whole

Choose your syrup

Syrup	Sugar	Water	Notes
Light	2.25 cups	5.25 cups	Lets the plum flavour lead
Medium	3.25 cups	5 cups	Sweeter, dessert-leaning
Water-packed	0	6 cups	No sugar; softer texture but safe (plums are already acidic)
Juice-packed	Unsweetened apple or white grape juice	—	Substitute 1:1 for syrup; good for lower-sugar diets

Bernardin does not fix one syrup for this recipe. The syrup follows the pack: light or medium for a raw pack, medium or heavy for a hot pack (p.147). Combine sugar and water, bring to a simmer, and keep hot until you pack.

We publish quantities for light and medium only. Bernardin’s syrup quantities are on page 140, which we have not read, so if you want a heavy syrup take it from your own copy rather than from us.

Whole or halved?

• Whole plums — less work, beautiful in the jar. You must prick each plum in several places. Bernardin is careful about what that buys you: pricking helps stop the plums bursting, but it does not stop the peel cracking. Best for clingstone and Japanese-type plums.
• Halved and pitted — packs more fruit, holds shape, easier to use. Best for freestone Italian prune plums. Cut along the seam, twist apart, lift out the pit.

Method

1. Warm the jars and canner. Fill the canner, bring to a simmer, and heat the jars so they don’t crack when filled.
2. Prep the plums. Wash. Prick whole plums all over, or halve and pit freestone plums.
3. Make the syrup. Simmer sugar and water until dissolved; keep hot.
4. Choose your pack. Raw pack: pack the pricked raw plums into hot jars to within a generous 1 cm of the top. Hot pack: warm the plums in the hot syrup one layer at a time over medium-low heat, about 2 minutes per layer; leave them to stand covered for 30 minutes; then bring the syrup back to a boil before packing. Bernardin publishes both and gives them the same processing time.
5. Fill. Pack plums into hot jars, pour hot syrup to cover, leaving 1 cm (½ inch) headspace. Debubble; wipe rims; apply fresh SNAP lids fingertip-tight.
6. Process in the boiling water bath — 20 minutes for 500 mL jars, 25 minutes for 1 L jars (Bernardin, p.147) — then adjust for your altitude band. Time starts at a full rolling boil.
7. Cool and check. Rest 5 minutes in the canner, lift to a towel, and leave 24 hours before checking seals.

Corrected 23 September 2026: this page used to send you to your own Bernardin edition for the processing time, in five separate places, because nobody here had read the recipe. It has now been read — Bernardin, Complete Book of Home Preserving (ISBN 978-0-7788-0137-5), page 147, Plums in Syrup — and the times are printed above: 20 minutes for 500 mL jars and 25 minutes for 1 L jars, for both packs. Three figures were wrong and are corrected with them. The batch was given as 4.5–5.5 kg (10–12 lb) of plums; page 147 publishes 2.7 to 4.5 kg (6 to 10 lbs). The yield was given as 6 × 1 L jars; page 147 publishes about eight 500 mL jars or four 1 L jars. The hot pack was given as a 1–2 minute warm-through in syrup; page 147 warms the plums one layer at a time for about 2 minutes each, stands them covered for 30 minutes, and returns the syrup to a boil before packing. That last one matters most, because our old method and Bernardin’s times did not belong together. The page also used to call light syrup the Canadian default and to say the recipe assumed it; page 147 makes the syrup follow the pack instead. The 1 cm headspace is unchanged. The sugar-and-water syrup quantities are unchanged and are still ours — they are not on page 147, so Bernardin’s name does not go on them.

If a jar doesn’t seal: the 24-hour rule applies.

Storage

• Cool, dark, dry place at room temperature
• Best quality 12 months — Bernardin’s guidance is to use home-canned food within one year. That is a quality window, not an expiry: the jar is as safe as the process made it. Colour, flavour and texture fade.
• After opening: refrigerate, use within one week (HealthLink BC)
• Inspect before opening — discard any jar with a bulging lid or off smell

Corrected 20 September 2026: this page previously gave an after-opening window of 5–7 days, a shorter figure specific to this food that no authority we could find publishes. HealthLink BC File #22 publishes one week for any opened home-canned container — “Once the container has been opened, refrigerate leftovers, and use within one week.” This correction makes the window longer rather than shorter: anyone who discarded a jar at 5–7 days was going by a number we had no source for. The shelf life of the sealed jar is unchanged.

Common problems

• Plums floated to the top. Normal and cosmetic. Hot-pack and snug packing reduce it. Safe regardless.
• Skins split and slipped off whole plums. They weren’t pricked, or the syrup was too hot too fast. Prick next time; heat gently. Still safe.
• Plums mushy. Too ripe to start, or over-processed. Use firmer fruit and process for exactly the recipe time.
• Jar didn’t seal. The 24-hour rule.

Ways to use canned plums

• Spooned over yogurt, oatmeal, or ice cream with a little syrup
• Baked into a plum cake or crumble in the depths of winter
• Alongside roast pork or duck
• Puréed into a quick sauce for pancakes
• Eaten straight from the jar

Next steps

• How to make plum jam — same fruit, skins on for pectin
• How to make plum sauce — the savoury, vinegar-acidified condiment
• How to can peaches in syrup — the stone-fruit companion, where Bernardin publishes no acid at all
• Canning altitude adjustments — required reading
• How long does home-canned food last — shelf-life context
• Water-bath canning pillar — the broader method