How to Make Strawberry-Rhubarb Jam in Canada

If strawberry jam is the gateway recipe, strawberry-rhubarb is the second jam every Canadian home canner makes. June through mid-July is the window: both crops are at peak, the seasons overlap by exactly the right amount, and they taste like summer in a jar together.

This guide covers the water-bath canned version (shelf-stable for 12 months) and the freezer-jam variation (no canner needed, brighter flavour). Both paths are simpler than plain strawberry jam because the rhubarb does some of the work.

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Why the pairing works

Strawberries on their own are tricky:

• Low in pectin — the structural fibre that makes jam gel
• Low in acid — pectin only activates in an acidic environment (pH < 3.5)
• High in volatile aroma — long cooking drives the strawberry flavour off

Rhubarb on its own works fine for jam (see our rhubarb jam post) but is tart enough that most people want sugar dialled up.

Pair them: the rhubarb brings pectin and acid; the strawberries bring sugar-friendly sweetness and brightness. The combined batch gels reliably with less commercial pectin and a shorter cook, which keeps the strawberry flavour intact.

The widely-published Canadian ratio is 2 parts strawberries to 1 part rhubarb by volume. Stick to that range (between 3:1 and 1:1 works; outside that, things shift).

What you need

• About 5 cups hulled, crushed strawberries (~750 g whole berries)
• About 2.5 cups finely chopped rhubarb stalks (~300 g)
• About 5–5.5 cups granulated sugar (exact amount on your pectin box)
• 1 × 170 mL pouch Certo liquid pectin OR 1 × 49 g pouch Bernardin Original powdered pectin — pick one, follow that box’s instructions
• Bottled lemon juice — 2 tbsp if the recipe calls for it (some do, some don’t)
• 7 × 250 mL Bernardin jars, fresh SNAP lids, bands
• Standard canning kit — water-bath canner, jar lifter, headspace tool, funnel, ladle, large heavy pot for cooking
• Cold plates in the freezer for the set test

The leaf rule (important if you’re new to rhubarb)

Rhubarb leaves are toxic. Use only the pink-to-red stalks. Cut leaves off and compost or trash them before bringing rhubarb into the kitchen. Full details in our rhubarb jam post.

The method (water-bath canned)

This follows the Bernardin/Certo standard recipe printed on every box of Canadian pectin. Read your specific box — there are small differences between liquid Certo and powdered Bernardin Original.

1. Prep the canner and jars. Fill the water-bath canner with enough water to cover the jars by 2.5 cm. Bring to a simmer. Place empty 250 mL Bernardin jars in the simmering water to keep warm.
2. Cold plates in the freezer. Put 3–4 small plates in the freezer now. You’ll need them at the end.
3. Prep the rhubarb. Trim ends and cut stalks into 1 cm dice. Smaller pieces break down better in jam.
4. Prep the strawberries. Wash, drain, hull, and crush in a wide bowl using a potato masher. You want crushed, not puréed — texture is good in jam.
5. Combine in a wide heavy pot. Add the crushed strawberries, diced rhubarb, and (if the recipe calls for it) 2 tbsp bottled lemon juice. For liquid Certo: stir in the sugar before pectin. For powdered Bernardin Original: stir in the pectin before the sugar. The pectin box is the canonical reference.
6. Bring to a hard rolling boil — a boil that cannot be stirred down. Stir constantly to prevent scorching.
7. Add the remaining ingredient (pectin if you used Certo Liquid; sugar if you used Bernardin Original powdered). Return to a hard rolling boil and boil exactly 1 minute, stirring constantly.
8. Test the set on a cold plate. Drop a teaspoon, wait 1 minute, push with a fingertip. Wrinkles = done. Slides = boil 1–2 more minutes and test again on a fresh plate.
9. Skim foam, ladle into hot jars. Leave 1 cm (½ inch) headspace. Wipe rims with a damp cloth.
10. Apply fresh SNAP lids and bands fingertip-tight.
11. Process in the boiling water bath for the time printed on your pectin box at your altitude band. Typically ~10 minutes at sea level for 250 mL jars; add for your altitude per our altitude-adjustments guide. Start timing when the water returns to a full rolling boil.
12. Cool 12–24 hours undisturbed, check seals. Concave centre that doesn’t flex = sealed.

The freezer-jam variation

If you don’t want to canner-process, use freezer-jam pectin (Bernardin Freezer Jam Pectin or Certo Light — different product from the regular Certo you’d use for canned jam; see our freezer jam post for the distinction).

Method changes:

• No cooking — mix crushed fruit, sugar, and freezer-jam pectin per the box
• Use about 4 cups total of fruit (in the 2:1 ratio: ~2.5 cups strawberries + 1.5 cups finely diced rhubarb)
• Slightly less sugar (typically ~3 cups instead of ~5)
• Stir 3 minutes, fill freezer containers leaving 1.5 cm headspace, stand 24 hours at room temperature, then freeze
• Shelf life: 12 months frozen, 3 weeks refrigerated after thaw

Note that freezer jam is softer-set and the rhubarb stays slightly chunky (it doesn’t break down without cooking). Many Canadians prefer this texture.

Storage (water-bath canned)

• Cool, dark, dry place — pantry or basement shelf
• Best quality 12–18 months
• After opening: refrigerate, use within 3–4 weeks
• Always check before eating for off odours, foam, or mould

Things that can go wrong

• Jam didn’t set. Most common: pectin under-mixed, sugar reduced from recipe, or didn’t reach a true hard rolling boil. Full troubleshooting + salvage paths.
• A jar didn’t seal. The 24-hour rule applies.
• SNAP lid reused (or you’re tempted to). Don’t. Single-use only.
• Jam too tart. The rhubarb-to-strawberry ratio is off — try 2.5:1 or 3:1 next time, or add a tablespoon of honey to the finished batch.
• Mushy strawberry pieces. Normal in any cooked strawberry jam. To keep more texture, use slightly under-ripe berries (about 25% of the batch) — they hold shape better.

When to make this versus plain strawberry vs plain rhubarb

Want	Make
First-ever jam, most forgiving	Strawberry-rhubarb (this post)
Pure strawberry flavour	Strawberry jam
Tart, less sweet	Rhubarb jam
No canner needed	Freezer jam (any of the above as a freezer variation)

Next steps

• Read the water-bath canning pillar for the broader method.
• SNAP lids reuse rules before you start.
• Altitude adjustments for the minute math.
• Coming next: garlic scape pickles (already up, late June) and dill pickles (July).