For more than ten years, we have raised a thornless blackberry cultivar with large, succulent berries. They don't have as much sweet flavor as wild blackberries, but are sure a lot easier to pick! The problem is some of the berries ripen on the top half of the berry, but the bottom half remains red and hard. Is there anything we can do? My solution has been to break those off and throw them to my chickens. If I leave them on the bush, they will eventually ripen on the bottom half but the berry is usually mushy and not good.
I have seen the same ripening problem in other berry patches. It seems to be worse with certain varieties and when we have something disrupt the ripening process, like hot temperatures, or short term moisture stress when the berry is filling out about 2-3 weeks before ripening. It definitely is what we call an abiotic stress or disease. Difficult weather and/or water conditions seem to make it happen.