I might see if I can find a recipe that doesn't take 3 days but still this worked really well. I got 5 1/3 pint jars worth out of these measurements. Personalised labels from Autumn Leah Designs on Etsy. I prefer powdered pectin but sometimes I can only find liquid pectin pouches which are fine too - just follow the instructions inside the box.
Strawberry Jam (using pectin)
4¼ pounds Fresh Strawberries
6⅓ cups White Sugar
6 ounces, fluid Lemon Juice
4 Tablespoons Powdered Pectin
You will also need a large non-reactive glass or metal bowl, a very large pot and 9 sterilized 1/2-pint canning jars, lids and bands.
Gently rinse the strawberries and allow them to air dry. Remove the stem and hull from each berry. Quarter any berries that are larger than 1 1/2 inches (4 cm), and halve berries that are larger than 3/4 inch (2 cm). For berries smaller than 1/2 inch (1.25 cm), leave them whole.
In a large bowl, mix the strawberries with about half of the sugar (3 1/3 cups or 625 g) and half of the lemon juice (3 ounces). Leave them to macerate for 12 hours or overnight. If it is cool, you can leave them on the counter. If it is warm, refrigerate.
Pour the now juicy strawberry-sugar mixture into a large pot and bring to a simmer. Allow to simmer for a minute then remove from heat. Cool for a few minutes in the pan, then carefully pour into a large heat-proof bowl and refrigerate overnight. When cold, cover with a sheet of waxed paper, making sure that the berries are all fully submerged in the juice. The berries can be stored in the refrigerator for up to 2 days at this stage.
Measure the remaining white sugar (3 cups or 625 g) and put it into a bowl. Add the pectin powder and mix until combined.Transfer the strawberry syrup mixture into a large pot. Bring to a simmer and add the pectin sugar blend, stirring until dissolved. When the sugar is dissolved, add the remaining lemon juice (3 ounces) and bring to a full rolling boil. Continue to boil until the mixture reaches 221 F, which should take between 15 and 20 minutes.***
Remove from the heat and allow to cool for 2 to 3 minutes.
Fill up the canning jars according to proper canning protocols, making sure that the strawberries are distributed evenly.
Process according to your favorite method. I used the hot water canning method and boiled jar, with lids only lightly screwed on, in 2 inches water for 20mins (will differ due to altitude).
Store in a cool, dark place. Lasts up to year.
***NOTE: This foams rapidly and voluminously, so be sure to use a very large pot and do not leave unattended for even a second. If it threatens to foam over, turn down the heat and stir to dissipate the foam. You can also add a small (1/2 teaspoon) pat of butter as you bring it to a boil, which helps dampen the excessive foaming remarkably well and does not affect the taste or shelf life of the jam.