Wash and strain boysenberries, then add to a medium Dutch oven. Cover with sugar, citrus juice, and zest, then mash with a potato masher.
Bring the berry mixture to a boil and continue to boil vigorously over medium-high heat, stirring often, for 5 minutes. Add orange blossom water (optional).
Test the jam's consistency by placing a few tablespoons on a small saucer, then place in the fridge for 15 minutes. If you are happy with the consistency, ladle the hot jam into sterilized jars, leaving ¼ inch headspace. Otherwise, boil for a few more minutes or until the desired texture is achieved.
Wipe the filled jars' rims with a clean, damp dish towel or paper towel (this will give you a better seal). Add sterilized lids and collars, then hand-tighten.
Canning Instructions
To can your boysenberry jam, process filled jars in boiling water for 10 minutes. For every 1000' above 1000' of elevation, add 1 minute of processing time. Remove jars and allow to seal. If any jars don't seal, consume those first or refrigerate. Or gift to friends, letting them know that the jam needs to be refrigerated.
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Notes
To make seedless boysenberry jam, you first need to mash the fruit through a food mill, allowing the pulp and juice to drain out, leaving the seeds behind. Then proceed with the recipe instructions.
Be sure the jar lids seal before labeling with the type of jam and the date.
Store boysenberry jam jars in the pantry for up to a year.
Once the jars are opened, store them in the fridge and consume within 3 months.