Yeah, I figure the extra space won’t hurt, just use a little more CO2. Space to store it is probably the main thing.
I’m intrigued that treating them may allow them to keep longer at room temperature before getting undesirable texture. I’m put off by the texture of soft non-astringent persimmons.
I’m sure I’ve never harvested more than could fit in your container at one time, and those were non-astringent, but one can dream My Saijo is growing great, still has its first and only piece of fruit on it.
What did you use for the nut inside the tub to secure the threaded end of the quick connect?
edit: looks like the threads on the quick connect nipple are 1/8-27 NPT. But I can just use the part that’s already attached to it as a nut. I’ll put a couple of O-Ring spacers on the outside so it won’t bottom bout before it’s squeezing to the box.
I have not met an american persimmon yet that needed anything other than more hang on the tree time … or more wait on the counter time to ripen.
More hang on the tree time does it for rich tooie… they definately tree ripen. Or you can pick off the tree once ripe color and a bit soft… and give them 4-7 days on the counter and they are completely non astringent.
Some of the wild dv here at my place… have to wait longer…if you pick them off the tree when ripe color and quite soft… if you try them in 2 3 4 days… zap. Wait a week or more and they eventually lose all astringency.
3 roadside trees i harvested from this year… 2 were tall and i had to try ripe fruit that had dropped to ground… nice and ripe and no astringency. The other is my walmart roadside small tree. It holds its fruit… even after quite ripe. I have to go on softness level on it…if very soft… no astringency… but if still a little firm or lumpy… watch out. With more time they eventually get quite soft ripe and no astringency.
I cant tell that frost has helped with persimmon ripening here or not… we had 3 nights (29-32)… and i harvested wild dv here at my place and roadside… that were still quite astringent.
Again… with those… more counter top time did the trick.
Do you still use 3 days in the chamber for Giombo? Did you experiment for an optimal time, or just found something that worked and stuck with it?
Sounds like cultivars may differ and how long since its been picked, and how stored, before treatment may matter too.
I have 4 fruit that are still pretty firm. I’ve never tasted Giombo, and would like to try/eat these by Saturday. Earlier is better. I’m planning to put my chamber together today.
I still don’t have any persimmons of my own to test (fingers crossed for next fall), but one thing that I see mentioned in research papers on the subject that I haven’t seen explored thoroughly in the hobbyist space is the effect of temperature. I’ll have to find it again, but one source suggested an anoxic environment (I think CO2) at 40c for 2 hours or 60c for one hour to remove astringency. However, if you leave it in too long at 60c, the astringency can come back and not be removable. I’ve also seen some videos from parts of China where they give their persimmons a soak for a couple days, but they start with hot water, so there’s probably something to that. I think submerging persimmons in a cooler with a sous vide circulator would be an easy way to achieve this time and temp combo. I also wonder if American persimmons might respond to treatment at higher temps.
Edit: Found my original post. It’s 5h at 40c or 1/2-1 h at 60c. Going over 2h at 60c permanently sets the tannins.
I’m also unaware of anyone having success. However, I’ve never read any reports of someone trying at higher temps. My gut says that it’s got to be possible, as it’s more likely from an evolutionary standpoint that the tannins differ in quantity than quality. Just have to figure out the magic combo. And I bet acetyldehyde would do the trick, but we’ve already determined that’s not safe for home use.
This is sensible, and I was inclined to believe it myself. I just don’t see any evidence that it is true.
Presumably the quantity of tannins in a nearly ripe American fruit is fairly low. If quantity were the only issue, then a standard technique that works with Asian persimmons (e.g., CO2, ethanol) should work with nearly ripe Americans. But it doesn’t seem to.
Maybe it’s not so much the quantity of tannins but a difference in composition or enzyme activity that inhibits or metabolizes acetaldehyde before it can bind to and precipitate tannins.
Either way, it’s almost certainly a question of “how much” than “how so”. New metabolic pathways are difficult to evolve; there would have to be a huge advantage to the change to allow any mutations that completely change the pathway to not be selected against. How active those pathways is pretty easily evolved; so long as it still works, there’s not much selection pressure in any particular direction and it can drift up or down. If it got outside certain parameters, it would be selected against unless it presented some other reproductive advantage.
Thanks for mentioning temperature. I did some sloppy experiments with store bought Hachiya, probably last winter after reading an abstract or something regarding.
I think I vacuum sealed and then used immersion circulator to condition them sous vide. If I recall, it did remove the astringency, but also softened the flesh.
It was at lower temperatures. Probably between room and yogurt temperatures. I’d have to dig around to recall. I don’t remember if I posted about it here.
I haven’t actually used mine this year at all. My non-astringent kakis had a record harvest that has kept my family happy (they don’t like the soft kakis fresh), so I haven’t needed to treat any this year and have just been dehydrating all my astringent kaki fruit (which my family also likes). I didn’t do enough batches in previous years to try shorter times, but it could work. It’s important to let the treated persimmons sit a while (overnight?) before you taste them. I made the mistake of tasting my first ones straight out of the bin, and they were still astringent (and carbonated). But after leaving them overnight after opening the chamber, the fruit that had been treated for 3 days were no longer astringent. It’s possible that it could take less time for some cultivars or fruit that is closer to ripening when treated. The Nikita’s Gift fruit that I treated was still astringent after 3 days, so I’m not sure this CO2 treatment is even effective with hybrids or if it just takes longer.
Thanks, that’s the sort of information I was after. Is there a reason you tried 3 days initially, rather than something shorter? Also, I’m wondering if size matters ?
I’ll probably take one out tonight and try it tomorrow. The other two I can put back and re-flush with CO2.
Those are obvious questions, aren’t they? I would like to know the answers too, but I haven’t experimented with shorter periods of treatment.
The first time I tried treating astringent kakis with CO2, I did it for only one day. I took one treated fruit out and tasted it immediately. It was still astringent, so I put them all back in CO2 for a second day. The fruit I tasted after the second day was still astringent, so I put them back in CO2 for a third day, and was very disappointed when they were still astringent after three days. So I gave up and just left the open tub on the counter. Out of curiosity, I tasted one the following morning, and it wasn’t astringent. I haven’t tried shorter periods of CO2 exposure - I just replicated what I knew worked with Giombo with other cultivars - Eureka, Giboshi, Tecumseh, Nikita’s Gift. Three days was enough for Eureka, Giboshi and Tecumseh, but not for Nikita’s Gift. The trick is that I could only do one batch at a time, and the fruit eventually soften up on their own if you don’t get around to treating them in time. So it’s a limited window of time in which to experiment. I look forward to your results and wish you had more fruit to work with!
Ethanol works for both Kasandra and JT-02 / Mikkusu, but I suppose it’s a genetic roulette. I’d be very surprised if there weren’t some hybrids that behave more like Americans, i.e., not responsive to ethanol, or CO2.
I agree with all of this. Obviously you have some expertise.
Presumably astringency is a strategy that the persimmon uses to deter animals from eating the fruit before the seeds are viable. If that’s right, then there is some selection pressure – if animals eat the seeds, you fail to reproduce. But the plant also needs a mechanism for removing the astringency once the seeds are viable – if the animals don’t eat the fruit, they won’t spread. So better yet, there’d be 2-3 mechanisms.
Let’s imagine that the primordial persimmon ancestor evolved two mechanisms for removing astringency. In other words, the “how so” was multi-faceted from the outset. Then maybe, as D. virginiana and D. Kaki evolved, each came to depend more on different mechanisms. In other words, a different “how so” is predominant in the different species.
It might be interesting to know how other persimmon species, such as D. lotus, respond to ethanol and CO2.
I’ve not tried cultivars outside of Hachiya and Fuyu but below is a photo of dehydrated astringent Hachiya slices.
As detailed in this thread, they were store-bought, still hard/astringent, peeled and sliced, and placed into a food dehydrator at 140°F for 17 or 18 hours. They come out very sweet and delicious. You may wish to try it with other varieties.
My Saijo is growing great, still has its first and only piece of fruit on it.
