Strawberry Jam for Canning

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. 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. 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. 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. 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. 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. 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. 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