3/4 of the amount of ume plums (If you don't have sugar) Honey
Gently wash the ume plums thoroughly, removing dirt and smoothing out the surface.
Be sure not to damage the skin of the ume plums.
Remove the stem ends one by one, using a toothpick.
Pat dry, put them in a plastic bag, and freeze overnight.
Sterilize a large container and a lid with shochu (35% alcohol) thoroughly.
Put the ume plums, then sugar into the container, and layer them in that order so that all the plums are touching the sugar.
Note Use a container that is big enough to put in the whole ume plums and sugar.
Use a 8 liter container if using 4 kg ume plums and 4 kg of sugar.
On the day you put the ingredients in the jar, the jar will develop condensation on its surface since the ume plums are frozen.
The floor will get soaked, so it's probably a good idea to place the jar on a floor cloth on in the sink...
Note If you can't fit all the ume plums in even if you are using the amounts listed in the recipe and an 8 liter container as specified, leave it for a day or so.
The ume plums in the container should sink down, at which point you can add the remaining ume plums and sugar.
Shake the container every day (several times a day, if possible) to mix together well.
By mixing the thick syrup that settles in the bottom back in, the ume plums will release their juices faster.
I put "1 week" in the title of this recipe, but that is estimated minimum amount of time required for the sugar to dissolve.
The younger the ume juice is, the more you can enjoy its fruity aroma.
But after the ume plums have sunk to the bottom, the longer they are kept in the juice, the more the aroma from the core (which is called the "jin") will be infused in the juice, and the color will turn brown.
So I recommend adjusting how long you keep the ume plums in the juice depending on the taste you prefer.
You can omit this step Remove the ume plums from the juice, transfer the juice to a pot, and heat over low heat.
But be sure not to bring it to a boil.
Remove the scum, and simmer to thicken (ideally, do this in a double boiler).
You can leave the ume juice as-is, but simmering it prevents it from fermenting, and you can store the juice for a long time.
Note Do not place a jar with a hot syrup from Step 7 in cold water to chill!
My friend's jar of ume syrup jar broke because of this, and her week of hard work came to nothing.
Dilute the syrup by 5-6 times to drink.
FYI: When you remove the ume plums from the juice, if you find some ume plums that are not so wrinkled, remove the cores, chop them up finely, and simmer them to make ume jam.