In my experience the ripeness of the seed is very important and a good indicator of the possibility to grow palatable persimmons in a given area. Of course in this case seedless persimmons do not make a good subject…
I found that if the seeds are not ripe but still somewhat greenish and otherwise brownnish but still soft the fruit is very unlikely to loose astringency. This happens in a cooler climate with short season and very importantly “fewer heat hours” (hours during which temp is 77F +) . Under such conditions most persimmon will perhaps produce quite nice looking orange fruit but somehow the astringency doesn’t disappear, not even when the fruit turns soft. This is especially the case with southern 60 chromosome types.
I have tried the alcolhol treatment to remove astringency but without succes and CO2 treatment doesn’t work either. Although it works perfectly on the Asian persimmons that I grow here.
@Mikatani – Both my Prok and my IKKJ have been seedless. The Prok’s got tiny undeveloped proto-seeds, flat and maybe 1/8" wide. In roughly 50 fruits harvested and eaten / processed so far, I’ve found two seeds that look fully developed (and dark). So basically, seed state is not a useful indicator for me here.
There’s like a critical point where this is possible. One week early for pawpaws, I’d say yes. Two weeks early, I’d say no. American persimmon are more forgiving because they are easier to pick. There is an estate nearly with what I believe is Prok and Geneva Long and a neighbor has a Meader. They will ripen on the counter nicely so long as there is a bit of squishiness when I pick them.
What is the time frame that American persimmons will be edible once ripe? Obviously pawpaws have about a one week window, maybe a little bit more if you pick a bit early and refrigerate (I have a few currently in this boat).
@tonyOmahaz5 has noted a few times that Prok will continue to ripen off the tree once it has started turning color.
Probably until you can still find them palatable. American persimmon benefit from bletting, pawpaws do not obviously.
Interesting to know if I need to pick my persimmons before ripe. Personally I have have 100% non-astringent fruit from my American Persimmons by checking daily and picking attached fruit when they feel soft or collecting fruit that has fallen with 24 hours (sometimes submersion to drown ants is required).
If the fruit is non-astringent when you harvest, I don’t see a need to do anything different. I guess I don’t understand your question.
My problem was that despite following exactly your method, I was still getting fruits 80% of which were astringent.
Just a bit of data – As the season continues, my astringency problem has diminished. Yesterday I ate 4-5 fruits freshly fallen from the tree. I didn’t notice any astringency while eating them, though there was a slight astringent afterglow. Trees picked from the tree are still risky.
Results of an experiment to report. . . .
Three days ago, I picked some fruit from Prok. These were apparently ripe or nearly ripe fruits, still adhering to the tree. Most were entirely orange; some still showed some green. Similar fruits tasted immediately after picking tasted more or less astringent.
I put half of the fruits in a plastic bin with both (a) a small glass of diluted ethyl alcohol (vodka), as a source of water vapor; and (b) a ripe banana, as a source of ethylene. My intent was that alcohol vapor and/or ethylene would hasten ripening and eliminate astringency. I put the other half of the fruits in an identical bin that was otherwise empty, as a control. I covered both bins and stored them in low/no light conditions at room temperature.
Today I opened the bins. As hoped, all of the fruits in the treatment condition (alcohol plus ethylene) were fully ripe with no astringency. But unexpectedly, all of the fruits in the control condition were also ripe with no astringency. So, there was no material difference between the fruits in the two bins.
I conclude that three days of warm storage post-picking is sufficient to ripen not-quite-fully ripe Prok persimmons. Adding alcohol vapor (from vodka) and ethylene (from a ripe banana) appears unnecessary.
A forum member just “liked” this post, so I feel obligated to update.
I wish that my post above was the end of the story. At that time there were still hundreds of fruits on the Prok tree. I picked many well into November. Unfortunately, a large proportion of the ripe fruit remained astringent. Highly astringent fruit are disgusting. But even slightly astringent fruit leave an aftertaste (after-sensation) that ruins the eating experience for me.
My investigation of this issue was restricted by the fact that I ruptured an Achilles tendon in late August. By early October (above), I was finally picking these persimmons on crutches with a protective boot on my left foot. What this all means is that in general I couldn’t pick as much as I might have hoped, and in particular I couldn’t pick at all near the beginning of the season. I have no idea whether warm growing conditions (e.g., Sept / early Oct) helps remove astringency.
Bottom line: I decided to top-work TOTALLY the Prok tree, especially with American varieties that may be better behaved. It is now grafted with Barbra’s Blush, H63A, and Dollywood, as well as the hybrid JT-02 and some Asians.
Someone just liked a pot of mine within this thread, so I’m updating . . . .
My initial comments here had a note of optimism. I wanted to correct that impression because later I was disappointed and discouraged. Eventually I gave up trying to make my “Prok” fruit non-astringent using ethanol. Success was sporadic at best. At this point, I’m not convinced that the variety really is Prok. I think it may have been mislabeled OR the rootstock tree was allowed to take over.
As noted above, I top-worked the tree. Last autumn, I picked the Americans H63A, Barbra’s Blush, and Dollywood; as well as the hybrid JT-02. These other varieties were much better. H63A and Barbra’s Blush ripened early enough to be edible off the tree with minimal astringency. Both were quite good. Dollywood ripened later and was never as good, though that may be a result of a late spring; I never tried to ripen it indoors. JT-02 produced a huge crop (>70 fruits on 2 grafts); I ripened these indoors and they were very good.
My reading of the comments on this forum (which are consistent with my experience) is that ethanol is not generally effective in removing astringency from American fruits. Neither is CO2. It may sometimes appear that ethanol is working, but I think that’s just normal indoor ripening.
If you have to do anything at all it’s not something you want.
Most all varieties you can pick somewhat early and they will finish on the counter (Dollywood). I let all of them set on the counter a little just to make sure. Most of them also taste better the more wrinkled and ugly they get on the counter.