Homemade Strawberry Jam for Canning

There is a particular satisfaction in a row of strawberry jam jars cooling on the counter, lids pinging one by one as they seal. This recipe follows the tested powdered-pectin method used by the National Center for Home Food Preservation: a full rolling boil, exact headspace, and a water-bath process timed for half-pint jars. Followed as written, it gives you a bright, spoonable jam that keeps the flavor of peak-season berries all year, the same pantry logic behind our Canned Apple Pie Filling.

Strawberries are low in natural pectin, which is why this recipe uses powdered pectin rather than hoping a long boil will set the batch. The pectin method is faster, keeps the color vivid red instead of brick-dark, and — most importantly for canning — it is a tested formula. Do not reduce the sugar: in a pectin-set jam, sugar is part of the preserving and setting system, not just sweetness. Low-sugar batches need a specially formulated low-methoxyl pectin and their own tested recipe.

Before you begin, read the whole recipe once, set out every tool, and check the current National Center for Home Food Preservation guidance for your altitude. Canning rewards preparation and punishes improvisation, and jam waits for no one once it reaches the boil. Times below are for elevations of 0 to 1,000 feet; higher elevations need added processing time from the current USDA table.

Why the boil must be a full rolling boil

Powdered pectin only sets reliably when the mixture reaches a full rolling boil — a boil so vigorous it cannot be stirred down — twice: once with the pectin to dissolve and activate it, and once after the sugar goes in, held for exactly 1 minute. A gentle simmer will leave you with delicious strawberry syrup that never gels. Use your largest pot: jam foams up dramatically and needs at least four times its volume in headroom. Set a timer before the second boil starts.

Headspace, rims and fingertip-tight

Three small habits decide whether jars seal. First, headspace: jam needs exactly 1/4 inch (6 mm) of space between the jam surface and the rim, measured with a headspace tool or ruler — too little and jam expands out under the lid, too much and the jar may not exhaust enough air to seal. Second, wipe every rim with a clean, damp cloth before the lid goes on; a single seed or sugar crystal can hold the seal open. Third, screw bands on fingertip-tight only — snug, not wrenched — so air can escape during processing and a vacuum can form as the jars cool.

Ingredients

• 5 3/4 cups crushed ripe strawberries (about 2 1/2 lb / 1.1 kg whole berries, hulled)
• 1/4 cup bottled lemon juice (60 ml)
• 1 package powdered fruit pectin, 1.75 oz (49 g)
• 7 cups granulated sugar (1,400 g), measured into a separate bowl before you start
• 1/2 teaspoon unsalted butter (2 g), optional, to reduce foaming
• 9 half-pint (8 oz / 250 ml) canning jars with new lids and sound bands

Amounts are for the yield below. US customary measures first, grams in brackets for scale users.

Step-by-step instructions

1. Prepare the canner, jars and lids. Fill a boiling-water canner about two-thirds full of water and bring it toward a simmer. Wash the jars, lids and bands in hot soapy water and rinse well. Keep the clean jars hot in the canner water or a 200°F (93°C) oven so hot jam does not shock cold glass. Lay a clean towel beside the stove for the finished jars.
2. Crush the berries and combine. Crush the hulled strawberries a layer at a time with a potato masher — you want a crushed, juicy mixture with small pieces, not a puree. Measure exactly 5 3/4 cups of crushed berries into a large, deep pot. Stir in the lemon juice and the powdered pectin until the pectin dissolves, and add the butter, if using.
3. First rolling boil. Bring the berry mixture to a full rolling boil over high heat, stirring constantly so nothing catches on the bottom. The boil must be vigorous enough that it does not stop bubbling when you stir — this is what activates the pectin.
4. Add sugar and boil hard for 1 minute. Pour in all the measured sugar at once and stir to combine. Return the mixture to a full rolling boil, stirring constantly, and the moment it reaches that unstirrable boil, start timing: boil hard for exactly 1 minute. Remove from the heat and skim off any foam with a clean metal spoon.
5. Fill the jars, 1/4-inch headspace. Working quickly, ladle the hot jam into the hot jars using a canning funnel, leaving exactly 1/4 inch (6 mm) of headspace. Slide a nonmetallic spatula or chopstick around inside each jar to release air bubbles, then re-check the headspace and add jam if it has settled. Wipe each rim with a clean damp cloth, center a new lid, and screw the band on fingertip-tight.
6. Process in the water bath. Load the jars onto the canner rack and lower them into the water, which must cover the jars by at least 1 inch (2.5 cm); add boiling water if needed. Cover, bring the water back to a full boil, and only then start timing: process half-pints for 10 minutes at 0 to 1,000 feet elevation (adjust for altitude using the current USDA/NCHFP table). When time is up, turn off the heat, remove the lid, and let the jars stand in the water for 5 minutes.
7. Cool, check seals, store. Lift the jars straight up with a jar lifter and set them on the towel, undisturbed, for 12 to 24 hours. Check the seals: lids should be concave and not flex when pressed. Any jar that did not seal goes in the refrigerator and is used within 3 weeks. Label sealed jars with the contents and date, remove the bands, and store in a cool, dark place for up to 1 year for best quality.

Nutrition estimate

Nutrition figures are estimates calculated from standard ingredient data for the yield stated. Your actual values will vary with brands, substitutions and portion sizes — treat them as a guide, not a guarantee.

Storage & reheating

Properly sealed jars keep best quality for up to 1 year in a cool, dark pantry; check the seal again before opening any jar, and discard without tasting any jar that has lost its seal, bulges, spurts on opening, or smells off. Once opened, refrigerate and use within 1 month. Unsealed jars from the original batch keep 3 weeks in the refrigerator. Nutrition estimate is per tablespoon (20 g) of finished jam, calculated from standard ingredient data — estimates vary with your berries and exact yield.

Homemade Strawberry Jam for Canning

★★★★★★★★★★ FryDaily kitchen score 4.9/5 — our own editorial rating from testing, not reader reviews.

Bright, spoonable strawberry jam, water-bath canned the tested way for a pantry shelf of summer.

Yield: 9 half-pint jars  ·  Scale: 1x2x3x

Prep30 minutes

Cook30 minutes

Total1 hour

Servings9 half-pint jars

Calories55 kcal

Ingredients

• 5 3/4 cups crushed ripe strawberries (about 2 1/2 lb / 1.1 kg whole berries, hulled)
• 1/4 cup bottled lemon juice (60 ml)
• 1 package powdered fruit pectin, 1.75 oz (49 g)
• 7 cups granulated sugar (1,400 g), measured into a separate bowl before you start
• 1/2 teaspoon unsalted butter (2 g), optional, to reduce foaming
• 9 half-pint (8 oz / 250 ml) canning jars with new lids and sound bands

Tick ingredients off as you prep, and tap a step below to mark it done as you cook. Scaling adjusts the listed amounts - seasoning to taste stays your call.

Instructions

1. Prepare the canner, jars and lids. Fill a boiling-water canner about two-thirds full of water and bring it toward a simmer. Wash the jars, lids and bands in hot soapy water and rinse well. Keep the clean jars hot in the canner water or a 200°F (93°C) oven so hot jam does not shock cold glass. Lay a clean towel beside the stove for the finished jars.
2. Crush the berries and combine. Crush the hulled strawberries a layer at a time with a potato masher — you want a crushed, juicy mixture with small pieces, not a puree. Measure exactly 5 3/4 cups of crushed berries into a large, deep pot. Stir in the lemon juice and the powdered pectin until the pectin dissolves, and add the butter, if using.
3. First rolling boil. Bring the berry mixture to a full rolling boil over high heat, stirring constantly so nothing catches on the bottom. The boil must be vigorous enough that it does not stop bubbling when you stir — this is what activates the pectin.
4. Add sugar and boil hard for 1 minute. Pour in all the measured sugar at once and stir to combine. Return the mixture to a full rolling boil, stirring constantly, and the moment it reaches that unstirrable boil, start timing: boil hard for exactly 1 minute. Remove from the heat and skim off any foam with a clean metal spoon.
5. Fill the jars, 1/4-inch headspace. Working quickly, ladle the hot jam into the hot jars using a canning funnel, leaving exactly 1/4 inch (6 mm) of headspace. Slide a nonmetallic spatula or chopstick around inside each jar to release air bubbles, then re-check the headspace and add jam if it has settled. Wipe each rim with a clean damp cloth, center a new lid, and screw the band on fingertip-tight.
6. Process in the water bath. Load the jars onto the canner rack and lower them into the water, which must cover the jars by at least 1 inch (2.5 cm); add boiling water if needed. Cover, bring the water back to a full boil, and only then start timing: process half-pints for 10 minutes at 0 to 1,000 feet elevation (adjust for altitude using the current USDA/NCHFP table). When time is up, turn off the heat, remove the lid, and let the jars stand in the water for 5 minutes.
7. Cool, check seals, store. Lift the jars straight up with a jar lifter and set them on the towel, undisturbed, for 12 to 24 hours. Check the seals: lids should be concave and not flex when pressed. Any jar that did not seal goes in the refrigerator and is used within 3 weeks. Label sealed jars with the contents and date, remove the bands, and store in a cool, dark place for up to 1 year for best quality.

Calories: 55 kcalProtein: 0 gCarbohydrates: 14 gFat: 0 gSaturated fat: 0 gSodium: 0 mgFiber: 0 gSugar: 13 g

Tested in the FryDaily kitchen, October 2026. Printing? This card is designed to print cleanly on its own.

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