Water-bath canningStrawberries

Strawberry jam with Original Fruit Pectin

Canada’s jam. Eight jars in under an hour, set every time, from the berries picked the same morning or from the freezer in January.

Makes

About 8 × 250 ml jars

Active time

40 minutes

Total

1¼ hours including processing; 24 hours to cool and set

Strawberries

Photo ewen and donabel on Flickr · CC BY 2.0

Before you start

What keeps this jar safe

  • The sugar and fruit amounts are the pectin maker’s recipe: 1,250 ml crushed fruit, 1,750 ml sugar, one 57 g package of Original Fruit Pectin. Cutting the sugar with regular pectin gives a runny jam that can mould; for less sugar, use a no-sugar-needed pectin and its own recipe instead.
  • Powdered and liquid pectins are not interchangeable — they go in at different points and want different sugar. This recipe is for Bernardin Original (powdered) pectin.
  • Boil hard for exactly 1 minute after the sugar returns it to a rolling boil. Less and it will not set; much more and it goes stiff and dark.
  • Process the jars in the boiling-water canner the full 10 minutes. Inverting jars or sealing with paraffin wax are not safe substitutes.
  • Do not double the batch. Jam that is too deep in the pot cannot reach the gel point before it overcooks.

This follows Bernardin: Classic ‘Easy’ Strawberry Jam (Original Fruit Pectin). Quantities, acid and times are theirs; do not scale the vegetables without scaling everything, and do not change the vinegar, lemon juice or processing time.

Ingredients

  • 1,250 ml (5 cups) crushed strawberries — about 2.5 L (2½ quarts) whole berries, roughly 1.5–1.7 kg
  • 1,750 ml (7 cups, about 1.4 kg) granulated sugar
  • 60 ml (4 tablespoons) lemon juice
  • 1 package (57 g) Bernardin Original Fruit Pectin (powdered)
  • ½ teaspoon (2 ml) butter or margarine, optional, to cut the foam

Processing

Jars
250 ml (half-pint) · 125 ml (quarter-pint) same time
Headspace
0.5 cm (¼ inch)
Time at 0–300 m (0–1,000 ft)
10 min
Higher up
Same time for 250 ml jars. Above 305 m (1,000 ft) add 5 min; above 915 m (3,000 ft) add 10 min; above 1,830 m (6,000 ft) add 15 min; above 2,440 m (8,000 ft) add 20 min.
Why altitude changes the time →

Method

  1. 1

    Put 8 clean 250 ml jars on the rack of a boiling-water canner, cover with water and heat to a simmer (82 °C, 180 °F). Wash the lids in hot soapy water and set them aside dry; Bernardin lids are not pre-heated.

  2. 2

    Wash and hull the strawberries. Crush them one layer at a time with a potato masher — a child’s job, in a wide bowl — and measure exactly 1,250 ml (5 cups). Measure the sugar into a separate bowl.

  3. 3

    Put the crushed berries and lemon juice in a large, deep stainless-steel pot with the butter, and whisk in the pectin until it dissolves.

  4. 4

    Over high heat bring to a full rolling boil, one that keeps boiling when you stir. Add all the sugar at once and, stirring constantly, bring it back to a full rolling boil that cannot be stirred down. Boil hard exactly 1 minute, stirring the whole time. Take off the heat and skim the foam.

  5. 5

    Ladle the hot jam into one hot jar at a time to 0.5 cm (¼ inch) from the rim. Slide a plastic knife or bubble tool down the inside to free air, adjust the headspace, wipe the rim, centre the lid and screw the band down just until fingertip-tight. Return the jar to the canner and fill the rest.

  6. 6

    Make sure the jars are covered by at least 2.5 cm (1 inch) of water, put the lid on and bring to a full rolling boil. Start timing then: 10 minutes at 0–305 m (0–1,000 ft).

  7. 7

    Turn off the heat, remove the lid, wait 5 minutes, then lift the jars out without tilting onto a towel. Leave them 24 hours without touching the bands.

  8. 8

    Check the seals: a sealed lid curves down and does not flex. Remove the bands, wipe the jars, label and store. Any jar that did not seal goes in the fridge to eat first.

Keeps: Best within a year in a cool dark cupboard; the colour browns after that but the jam is sound while sealed. Refrigerate after opening and use within 3 weeks.

Variations: Frozen strawberries work: thaw, then crush and measure as fresh. For a chunkier jam, crush only half the berries and quarter the rest. Keep everything else exactly the same.

Tested source: Bernardin: Classic ‘Easy’ Strawberry Jam (Original Fruit Pectin). Checked October 2026. If a jar did not seal, refrigerate it and use it within a few days. Never taste anything from a jar that is bulging, leaking, spurting or smells wrong — when in doubt, throw it out without tasting.

The crop

Strawberries: when to pick, how to store, what else to make →

Freeze them. Hull, rinse, dry on a towel, spread on a tray, freeze, bag: whole berries that pour out loose all winter for smoothies, sauce and muffins. Sliced or crushed berries freeze well with 180 ml (¾ cup) sugar per litre of fruit for pie and shortcake. Strawberry jam is the other great use — a tested powdered- or liquid-pectin recipe, water-bathed 5–10 minutes depending on the recipe and your altitude — and uncooked freezer jam, which tastes more like the fruit than any cooked jam, keeps three weeks in the fridge and a year in the freezer. What does not work: canning strawberries whole. They are not on the tested list for canned berries because they collapse, float, bleach pale and lose their flavour in the jar; the way to keep strawberries in a jar is as jam. Dried strawberry slices and fruit leather are good but a lot of fruit for a little result.

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