How to Make Rhubarb Jam in Canada (Bernardin Method)

Rhubarb is the easier sister of strawberry. It’s tarter, holds its texture better in jam, and — unlike strawberries — actually wants to set. If your strawberry jam didn’t quite work, rhubarb is what you cook next.

This guide covers the Bernardin/Canadian method for plain rhubarb jam, with notes on the two paths (with or without commercial pectin) and on the leaf-toxicity rule every new gardener should hear before they start.

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First: the leaf rule

Rhubarb leaves are toxic. They contain oxalic acid and anthraquinone glycosides at levels that have killed people in documented Canadian and UK cases (rare but real). Use only the stalks — the pink-to-red ribs that grow up from the crown. Cut the leaves off in the garden or the moment you bring the bunch home, and compost or trash them. The stalks themselves are completely safe and have been a Canadian staple food for over a century.

If you’re picking rhubarb from a neighbour’s yard or a community garden, double-check before you start — what looks like a single innocent rhubarb plant is actually two zones of plant matter, one food and one not.

What you need

• 6–8 cups chopped rhubarb stalks (about 1 kg of fresh stalks, leaves removed and discarded)
• Granulated white sugar — about 4–6 cups depending on the recipe path (see below)
• Bottled lemon juice — 2–4 tbsp depending on the recipe path
• Bernardin Original powdered pectin OR Certo liquid pectin — only if you’re taking the commercial-pectin path
• 7 × 250 mL Bernardin jars, fresh SNAP lids, bands
• Standard canning kit — jar lifter, headspace tool, funnel, large pot for the water bath, second pot for cooking the jam, ladle, potato masher (rhubarb softens to a pulp on its own, but a masher helps)

Two paths

Path A: With commercial pectin (faster, firmer set)

Follow the recipe on your box of Bernardin pectin or Certo. The standard Canadian rhubarb-jam recipe published on Certo packages is roughly:

• ~5 cups chopped rhubarb → cooked down to crushed → ~4 cups
• ~5.5 cups granulated sugar
• 1 × 170 mL pouch Certo liquid pectin
• Yield: about 6–7 × 250 mL jars

Order of operations matters with pectin. Read the actual box. Liquid Certo: add pectin at the end after a hard boil with sugar. Powdered Bernardin Original: add pectin to the crushed fruit before the sugar. Don’t swap the order.

Cook time is short — typically a 1-minute hard rolling boil after pectin is in. The cold-plate test is your confirmation.

Path B: Without pectin (slower, softer set)

The traditional method. Rhubarb has enough natural pectin to set jam if you cook it long enough, but the result is softer — closer to a thick compote than a firm preserve.

• 6–8 cups chopped rhubarb
• 4–5 cups granulated sugar
• 2 tbsp bottled lemon juice (helps the pectin set and brightens the flavour)
• Yield: about 6 × 250 mL jars

Method without pectin:

1. Layer chopped rhubarb with sugar in a large bowl. Cover and refrigerate overnight (4+ hours minimum). The sugar pulls juice out of the rhubarb so you don’t have to add water.
2. Tip the macerated rhubarb-and-sugar mix into a wide heavy pot. Add the lemon juice.
3. Bring to a boil over medium-high heat, stirring constantly to prevent scorching.
4. Boil 15–25 minutes at a moderate boil (not the hard rolling boil you’d use with pectin), stirring often. The mixture will thicken and the rhubarb will break down to a soft pulp.
5. Cold-plate test starting around the 15-minute mark. You’re looking for the same wrinkle response on a frozen plate — see the cold-plate test in detail.
6. When the jam wrinkles on the cold plate, it’s done.

Pectin-free rhubarb jam will be softer than pectin-set strawberry jam. That’s normal and arguably better on toast (it spreads instead of clumping).

The cold-plate test

Set the test up before you start cooking:

1. Put 3 small plates in the freezer.
2. Around the 15-minute mark for the no-pectin path, or right after the 1-minute hard boil for the pectin path, drop a teaspoon of hot jam on a frozen plate.
3. Wait one minute.
4. Push the edge with your fingertip.
   • Wrinkles, holds its shape → done. Take off heat.
   • Slides smoothly but starts to gel → 2–3 more minutes.
   • Still liquid like syrup → 5 more minutes, then test again.

Always test on a fresh frozen plate. The full breakdown is in why didn’t my jam set.

Jar, process, store

1. Have your canner simmering with enough water to cover the jars by 2.5 cm.
2. Have warm jars ready, fresh SNAP lids and bands on the counter.
3. When the jam passes the cold-plate test, skim any foam off the top.
4. Ladle hot into hot jars. Leave 1 cm (½ inch) headspace — Bernardin’s standard for jam.
5. Wipe rims clean. Apply lids fingertip-tight.
6. Process in the boiling water bath for the time and altitude printed on your pectin box (Path A) or per the Bernardin no-pectin rhubarb-jam recipe (Path B). Typically ~10 minutes at sea level for 250 mL jars; add for your altitude band per our altitude guide.
7. Cool 12–24 hours undisturbed on a towel. Check seals.

Use our altitude-adjustments guide for the band lookup; open Bernardin for the exact minute count.

Storage

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

Variations

Strawberry-rhubarb jam — the classic Canadian pairing

The most-made Canadian jam after plain strawberry. The rough volume ratio is 2 parts strawberries to 1 part rhubarb, but use a tested Bernardin strawberry-rhubarb recipe specifically — the pectin/sugar/acid balance shifts versus either fruit alone.

The rhubarb brings:

• Extra pectin (helping the strawberry set without as much commercial pectin)
• Acidity (also helping the set, and balancing strawberry’s sweetness)
• A brighter flavour and a deeper pink colour

Rhubarb-ginger jam

Add ~30 g (2–3 tbsp) of finely chopped fresh ginger to a regular rhubarb-jam recipe at the start of cooking. Warming, less classically Canadian, very good on a cheese plate. Same processing time as plain rhubarb.

Rhubarb-vanilla jam

Split one vanilla bean lengthwise and add to the pot during cooking. Remove before jarring. Pricey but luxurious.

Rhubarb chutney (savoury)

Not a jam — uses vinegar instead of relying on fruit acid. Different processing rules. If interested, look up a Bernardin-tested rhubarb chutney recipe; the acidification is what makes it shelf-stable.

Common problems

• Jam didn’t set. Rhubarb usually does set, but a no-pectin batch can sometimes be too watery if the rhubarb was very young (high water content). Full salvage paths in the jam-set article.
• A jar didn’t seal. The 24-hour rule applies.
• Funny smell after months. Discard the whole jar. See here for what to check.
• Jam tastes flat. Probably under-acidified — add the lemon juice next time, even if the recipe was written for someone using already-acidic young rhubarb.
• Reused SNAP lids gave a failed seal. Don’t. Single-use only.

What to do with too much rhubarb

A mature rhubarb plant produces 2–4 kg per cutting and you can cut twice per season — that’s more rhubarb than most households can use in jam alone. Other Canadian uses:

• Freeze raw. Chop, tray-freeze, bag. Keeps 8–12 months. Pull out for winter pies and crumbles. (See freezing pillar.)
• Rhubarb compote. Cook with less sugar to a chunky sauce. Refrigerator-stable for a week or freeze.
• Rhubarb syrup. Cook chopped rhubarb with sugar and water until soft, strain. Use in cocktails (rhubarb gin tonic), spritzes, or over yogurt.
• Rhubarb chutney. Acidified and water-bath safe (tested recipes).
• Share. Rhubarb gardeners are notorious for trying to give it away. Find someone making strawberry jam — they’ll thank you.

Next steps

• Read the water-bath canning pillar for the broader method.
• Strawberry jam — the natural June companion.
• Why didn’t my jam set? — the troubleshooting.
• SNAP lids reuse rules before you buy your second box.
• Coming next: garlic scape pickles (late June).