Ingredients
- Canning supplies:
- 5 pints strawberries, hulled
- 6 tablespoons fresh lemon juice, strained
- 1 1/2 (49-g) packages powdered fruit pectin
- 10 1/2 cups sugar
- Large canning pot (large enough to completely submerge the jars in water)
- Canning tongs
- Twelve 8-ounce mason jars with lids and screw-on rings
- Wide-mouth canning funnel
- Canning rack to go inside the pot
Preparation
Step 1
Fill the canning pot two-thirds full of water and bring it to a simmer. Using canning tongs, submerge the mason jars in the water. Leave them there with the water simmering while you prepare the jam. Bring a small saucepan of water to simmer and add the jar lids (but not screw on the rings). Allow them to stay in the saucepan while you prepare the jam.
Place the strawberries on a large baking sheet and mash them until they're mostly mashed, but still have some large chunks in them.
Measure out 7 1/2 cups of the mashed strawberries and throw them in a pot. Add the lemon juice and give it a stir. Bring the strawberries to a boil over a high heat. Then pour in the powdered pectin and stir to combine. After that, pour in the sugar all at once.
Stir it around and bring it to a hard boil, which means you can't get the mixture to stop boiling when you try to stir it down. Allow to remain at a hard boil for 1 minute and 25 seconds. Turn off the heat, and then carefully skim off and discard the excess foam from the top of the jam. (Or you can let it cool and eat it as a snack!)
One at a time, remove the jars from the hot water. Place each jar on the counter top and insert the mouth of a wide-mouth canning funnel. Using a metal measuring cup or ladle, pour the preserves through the funnel into the jars. Stop when the jam is 1/4-inch from the top. (Do not under-fill the jars.)
Use a damp cloth to wipe off any stickiness from the jars. Then run a clean knife along the inside of the jars to remove any air pockets. Remove one of the lids from the simmering water and set it on top of a jar. Center it, and then screw the round ring on the outside of the jar. Don't over-tighten; just attach them gently. Continue until they're all filled.
Next, turn up the heat on the pot of water to high. When the water is boiling, set all the jars into the canning rack and lower the rack to submerge the jars in the water. Cover the pot and allow it to boil for 15 minutes. Turn off the heat and leave the jars in the water for 15 minutes more. Lift the rack from the water and remove the jars. Allow them to sit on the counter undisturbed for 24 hours; over a period of time, you should hear the lids pop as they seal themselves. It's a very satisfying sound!
After 24 hours, check the seals of all the jars: remove the rings from the jars and press your finger in the center of each jar. The center of each jar should be tightly indented and not give at all when you press your finger on them.
Store the jam in the pantry... or give it to your friends! Refrigerate the jam once the jars are opened.
Cook's Notes:
Jars should be made from glass and free of any chips or cracks. Preserving or canning jars are topped with a glass, plastic, or metal lid, which has a rubber seal. Two piece lids are best for canning, as they vacuum seal when processed.
To sterilize jars, before filling with jams, pickles, or preserves, wash jars and lids with hot, soapy water. Rinse well and arrange jars and lids open sides up, without touching, on a tray. Boil the jars and lids in a large saucepan, covered with water, for 15 minutes.
Use tongs when handling the hot sterilized jars, to move them from boiling water. Be sure the tongs are sterilized too, by dipping the ends in boiling water for a few minutes.
As a rule, hot preserves go into hot jars and cold preserves go into cold jars. All items used in the process of making jams, jellies, and preserves must be clean. This includes any towels used, and especially your hands.
After the jars are sterilized, you can preserve the food. It is important to follow any canning and processing instructions included in the recipe and refer to USDA guidelines about the sterilization of canned products.