My daughter brought me pounds of tiny grapes from her backyard... I followed the Ball Book's instructions .... cooked for the juice, strained and strained, let sit 2 days in fridge, strained again ...then used the exact measurements..and it never jelled. Now... I would like to ask your readers a question: "The Ball book calls for concord grapes and I used the measurements for backyard grapes. Is that the probable cause of my "failure", i.e., jelly never jelled.?!?"
I re-cooked the jars that I did not add pectin to.... and its not a good result getting too hard! (Turned dark like caramel in a "flash").
p.s. At the Henderson Farmer's Mkt on Thursday morning, the folks from Central Calif (not the Highland folks) always bring green tomatoes!