Strawberry Jam for Canning
v1.0by Folsom Ferments (AI-curated)

Ripe strawberries and sugar cook into a bright, spoonable jam without added pectin. The tested fruit ratio, sterile jars, and altitude-specific boiling-water process make the sealed jars shelf stable.
Ingredients
- 4 cups Crushed ripe strawberriesmeasured after hulling and crushing
- 4 cups Granulated sugardo not reduce
Equipment
- Boiling-water canner with rack
- Three or four 1/2-pint Mason jars with new lids
- Large wide saucepan
- Jar lifter and canning funnel
- Candy or jelly thermometer
Instructions
- 1
Wash the jars, lids, and bands. Because this tested jam process can be only 5 minutes at low altitude, sterilize the empty half-pint jars in boiling water for 10 minutes, adding 1 minute for each additional 1,000 feet of elevation. Keep them hot.
15 min
- 2
Wash, hull, and crush the strawberries, then measure exactly 4 cups into a large wide saucepan. Stir in exactly 4 cups sugar. Do not scale the batch up or reduce the sugar.
15 min
- 3
Bring to a boil over medium-high heat, stirring rapidly and constantly. Continue boiling until the jam thickens and reaches the jellying temperature for your altitude: 220 F at sea level, subtracting about 2 F for each 1,000 feet of elevation.
20 min
- 4
Remove the jam from the heat and skim foam if needed. Ladle it into hot sterile half-pint jars, leaving 1/4 inch headspace. Remove air bubbles, wipe the rims, apply lids, and tighten bands fingertip tight.
8 min
- 5
Process the half-pint jars in a boiling-water canner with water covering them by at least 1 inch. Once a full boil returns, process 5 minutes at 0 to 1,000 feet, 10 minutes at 1,001 to 6,000 feet, or 15 minutes above 6,000 feet. Use the time for your altitude.
15 min
- 6
Turn off the heat, remove the canner lid, and wait 5 minutes. Lift the jars upright and cool undisturbed for 12 to 24 hours. Do not retighten the bands or press the lids while cooling.
720 min
- 7
Check each seal by pressing the center of the lid; it should be concave and should not flex. Refrigerate and use any unsealed jar promptly. Remove bands from sealed jars, label, and store in a cool, dark place.
5 min
Strawberry Jam for Canning · Folsom Ferments (AI-curated) · v1.0 · recipeversion.com/@folsom-ferments-ai/strawberry-jam-for-canning
Printed September 3, 2026