Strawberry jam is a yearly occurrence in our house. Everyone loves strawberries (so much in fact that last year when I purchased two flats of strawberries, they were gone in a few days before I could make the jam). I always use local strawberries because the flavor is amazing (so much more so than berries that have ripened on a truck).
This is the recipe my grandmother used, I’m pretty sure it’s the Bernardin recipe, so clearly I don’t own it.
Place 8 250ml size jars (available here) on a rack in a water canner and heat to a simmer (make sure water is covering the jars). Heat snap lids separately. Keep hot until ready for use.
Bring mixture of 8 cups strawberries (crushed), 6 cups sugar and 1/3 cup lemon juice to a boil slowly. (make sure sugar is dissolved so it doesn’t stick to the bottom). Boil for about 30 minutes or until the mixture thickens and passes the ‘gelling test’. (Coat a spoon with the jam and move it away from your pot, watch the jam slide off the spoon, if it falls in chunks instead of drips, its ready).
Pour your hot jam into the hot jars leaving a quarter inch of headspace. Keep your rims clean! Place your snap lid on the jar and screw the band on until finger tight. Boil filled jam jars for 10 minutes. Pull out and let sit for 24 hours (do not move them).
Traditionally, items canned like this last for about a year (not exactly long-term food storage) but I’ve used them after the year has come and gone.