For those following along, grape jelly making was a success! Six jars plus a tester. It jelled! Only got to 218 °F before a cold plate test looked like it was boiled enough. I was hesitant to take it further since friend’s jelly with these grapes went to hard candy (they boiled by time, not temp). It’s so dense, its almost black. It’s not completely clear either. The twice filtered and settled juice had an almost satiny appearance. But wow! I tense flavor! Calling this a win!