This recipe is thanks to Ball® Canning Preserving Recipes.
4 cups crushed strawberries (about 1.25 kg)
3 tablespoons pectin
2 cups (440g) sugar
1-1/2 Tbsp good quality balsamic vinegar
4 (240 ml) half pint glass preserving jars with lids and bands
1.) Prepare boiling water canner. Heat jars and lids in simmering water until ready for use. Do not boil. Set bands aside.
2.) Place crushed strawberries and balsamic vinegar into a large saucepan or stockpot. Gradually stir in pectin. Bring mixture to a full rolling boil that cannot be stirred down, over high heat, stirring constantly.
3.) Add sugar, stirring to dissolve. Return mixture to a full rolling boil. Boil hard 1 minute, stirring constantly. Remove from heat. Skim foam if necessary.
4.) Ladle hot jam into hot jars leaving 1/4 inch (0.5 cm) headspace. Wipe rim. Center lid on jar. Apply band until fit is fingertip tight.
5.) Process in a boiling water canner for 10 minutes, adjusting for altitude. Remove jars and cool. Check lids for seal after 24 hours. Lid should not flex up and down when center is pressed.