yields approximately 4 pints
Most strawberry jam recipes call for adding pectin in order to properly gel the jam. Strawberries have very little pectin, so a source of pectin must be added. I prefer to use the natural pectin in an apple rather than add commercially produced powdered pectin. I find that an apple adds plenty of pectin along with a touch of tangy flavor that offers a nice counterpoint to the sweet earthiness of the fresh strawberries.
The grated apple softens as the jam cooks, releasing its pectin and becoming nearly unrecognizable in the finished jam. The apple peel should be removed before canning the finished jam. At our house, the apple peel coated in rich strawberry jam is a delicacy. It’s like the best fruit leather on earth and is happily devoured by the whole family!
1 ½ pounds strawberries, washed, stemmed, and cut into small pieces
2 cups (384 grams) granulated sugar
1 medium apple, prepared as directed below
Juice of ½ lemon (approximately 2 Tablespoons)
1 Tablespoon vanilla extract
Place several plates or large spoons in the freezer for use in gel test. If you are planning to can the jam, ready your canning pot, jars, lids, rings, and canning equipment. I like to use 4 or 8 ounce canning jars when processing this jam.
Using a sharp paring knife or vegetable peeler, remove the peel from the apple in long strips. Core and quarter the apple. Use a grater to grate the apple quarters. Add the grated apple and apple peel to a large non-reactive pot with the strawberries and sugar. Stir gently to combine and place the pot on a burner over medium heat.
Bring the mixture to a gentle boil, stirring occasionally. Reduce the heat slightly and continue to boil for 15 minutes, stirring as needed to prevent the sugars from burning. Using a slotted spoon, remove the strawberry pieces from the pot and transfer to a medium bowl. Removing the strawberries will help them to maintain a firmer texture in the final jam.
Continue to boil the liquid in the pot for another 15 minutes. Return the reserved berries to the pot and add the lemon juice. Stir to combine and continue to boil gently for another 15 minutes or until the mixture passes the gel test when allowed to cool on the chilled plates or spoons set aside in the freezer.
While the gel test may sound like a daunting scientific experiment, it is actually a simple, visual method for determining if your jam has reached the ideal consistency. This test will allow you to measure the finished consistency of your jam. If the mixture is too loose, it can be boiled further to allow a bit more of the liquid to evaporate. If the mixture has boiled too long and is slightly too thick, a small bit of liquid can be added to loosen the mixture before canning.
Performing the gel test involves placing a bit of the hot jam on a plate or large spoon that has been chilled in the freezer. When the mixture has been allowed to cool, the consistency can be accurately gauged. When cool, the jam should form a cohesive mixture, forming a wrinkle as it moves when pressed with your finger. If you run a finger through the small puddle of jam, it should split apart and then return to a cohesive puddle moments later.
Once the mixture has passed the gel test, remove the pot from the heat. Remove the apple peel and stir in the vanilla. Ladle hot jam into sterilized 4 or 8 ounce jars leaving ¼ inch headspace. Remove air bubbles from the side of the jar. Using a clean cloth, remove any residue from the rim of the jar. Place a lid on the jar and tighten with band. Gently lower the filled jar into the boiling water canner. Repeat until all jars have been added to the pot. Place lid on canning pot. Return water to a boil.
Once the water has returned to a boil, process half-pint jars of jam for 15 minutes. Turn off the heat and remove the lid from pot. Allow the jars to rest in the water for at least five minutes. Carefully remove jars to a towel lined baking sheet. Allow jars to cool up to 24 hours before checking the seals and labeling the jars for storage. A properly sealed jar of strawberry jam can be stored and used for up to one year.