Most of the non-native persimmons that North Americans find in stores — when they find them at all — are hachiya persimmons. They’re astringent, which isn’t a bad thing so long as you consume them when they’re ripe. But then that’s the problem. Not so much that astringent persimmons don’t ripen, but that there’s no telling when they’re going to ripen. For hachiya persimmons are like cats, they have minds of their own and do nothing in groups. Buy four or five together and one may ripen the next day, another the next week and another the next month.
What can you do to hasten the ripening of a hachiya persimmon? Nothing. Yes, you can put it in a paper bag in an attempt to concentrate the ripening ethylene gasses they give off. You can even put a big-time ethylene producer like a banana in there with it. That’ll help some, but for the most part you’ll still be at the mercy of the hachiya persimmon’s own mysterious biological clock.
That’s not a problem if you’re the type that likes to be surprised by a perfectly ripe persimmon every once in a while. I sure do. The challenge then is to sneak the thing into my pocket without anyone noticing, then divert the family’s attention long enough so I can skulk off to the garage or the basement with a spoon. What?
But what if you need a bunch of ripe persimmon flesh for a recipe? There you’re stuck. For once a hachiya persimmon is perfectly ripe, it’ll only keep a couple of days, even in the fridge. The solution, though rather unromantic, is to buy your persimmons well ahead of time and as they ripen scoop out the flesh, put it into an airtight container and freeze it until the next one ripens. In time — a couple of weeks, usually — you’ll accumulate enough for your recipe. And yes, persimmon flesh freezes very well.
Fuyu persimmons, if you can find those, are usually ready to go right out of the produce bin. As for the American variety, you can ripen — “blett” — them yourself if they aren’t edible when you pick them. Just put them in the freezer and let them freeze solid. When they thaw they should be ready to use. If not, repeat the process.