We know persimmons as golden, medium-sized fruits with honey-sweet flesh. However, the fruits of some species need frost to become edible, because they contain many adstringent tannins which are degraded by cold. The fruits first turn dark and soon frosted blue, as these pictures of the Chinese persimmon show.
This persimmon grows in the Frankfurt Botanical Garden. I had the opportunity to try a fruit in December, although this initially contradicted me; for my understanding, the fruit was overripe and decayed, but the botanist who guided me explained the ripening process to me. The flesh of this persimmon reminded me of a dried date: it was brown and soft, tasted sweet, perhaps caramel-like, but unfortunately also “not quite fresh”. A delicacy to get acquainted with, but worth a try.