Did you ever use Pomona’s Universal pectin?
You can make large batches. I would do 12 cups of blueberries, 4 C sugar, some cinnamon, and cook it down.
It made 7 pints of jam, just enough to fit a canner. And it all set beautifully.
You can also to sugar free.
Pomona’s Universal Pectin
https://pomonapectin.com/
I’ve heard of that pectin before. The two recipes I’ll be using for Raspberry and Blueberry Jam don’t require any pectin, but a longer cook-down time, which is fine with me. Then they’ll be water-bath canned.
I’ll also do a Raspberry Pie with a French Crumble top to put in the freezer for baking at a later date. Yummy!
Neighbor wants everything shelf-stable; she doesn’t have a lot of freezer space.
https://practicalselfreliance.com/blueberry-jam-no-pectin/#wprm-recipe-container-13106