Kaki (persimmon) is a phenomenal fruit. It is extremely adstringent when unripe, but extremely sweet and pleasant when it is properly ripe. Its full sweetness is complemented with distinctive kaki notes and silky mouthfeel. Truly a taste that stays on your tastebuds for many minutes and in your head for hours. But ripening a kaki at home is not that straightforward.
The challenge
In the autumn, during the kaki season, it is relatively easy to buy succulent, tender and fully ripened fruits. Everything is awesome, but you need to eat them really fast, since they will not last more than a week. You can also buy unripe fruits or, better still, grow them in your backyard. These fruits last much longer, the only problem is they need to be ripened properly.
The research
The common advice is to leave them long enough to ripen by themselves. Well this never worked for me. I always got shrivelled, dried out fruits with thick skin. Then an expert kaki farmer that sells kakis suggested ripening the kakis together with apples. This actually makes sense. Ripe apples release ethylene, a gas that speeds up the ripening process.
The results were mixed. Some of the kakis were ripe, while some were not, but that was not the main problem. The problem that remained was a relatively thick skin of the ripened fruits. A perfect kaki should have a tight, paper thin skin that literally bursts if you handle it too rough. Interestingly, the results were similar if the kakis ripened at room temperature or in the refrigerator. My guess is that the dry air is to blame. Since it is late autumn, relative air humidity is low and hence the fruits dry out. This was further confirmed when I left kakis in a plastic bag. Their skin was much thinner, close to the perfection. If closed in a plastic bag, the ripening effect is also accelerated, since ethylene cannot escape.
The solution
Closing the unripe kakis in a plastic bag together with a few apples is the best way to ripen them to perfection. Since they are closely packed and ripe fairly quickly, be sure to check them every week to take out the ripe ones before they burst and spoil.
