This recipe is adapted from one found in the Ball Blue Book. Every time I buy 12 oz. bags of frozen raspberries (to make jam), I see these 12 oz. bags of Whole Unsweetened Mixed Berries next to them (blackberries, strawberries, raspberries and blueberries). I always wondered what flavor it would have if made into a jam. Well, the mystery is over, and the jam is INCREDIBLE TASTING!