It may be the plums, but given that you peeled most of them, that sounds less likely.

Sometimes high level of spices can contribute bitterness. I've found with fruit butters I like the result much better with drastically reduced spice levels. The long cooking still results in a definite spice flavor but without the associated bitterness.

Carol

How did you peel them - cold peel or hot? If you do the tomato peeling thing and dip them in boiling water before peeling the bitterness from the skin is transferred to the meat.

Also our deadfalls tend to be more bitter throughout. We just leave the peel on and macerate them in extra sugar for 24 hours before turning them into jam. If still too bitter then you can stir additional sweetener into the jar after opening.

Dave

Thanks