I don’t know if anyone else has noticed this . . . If I don’t rinse dishes or utensils after eating persimmons, a hard crud forms that seems impervious to dishwashing detergent. Plates and knives come out of the dishwasher with streaks and spots of grey crust.
Thanks. When I tried to make a puree from mostly ripe but still somewhat astringent American persimmons, the puree developed a brown crust, which is similar. Maybe the tannins oxidize quickly.