If anyone in the NYC area is in the mood to try making umeboshi or umeshu, try the big H Mart stores in Flushing (the ones on Northern Boulevard) for fresh ume. I’ve spent the last week making both.
For umeboshi, the justhungry recipe works fine. Note that if you can’t get red shiso leaves until later, that’s OK – when you can get the shiso leaves, massage kosher salt into them, rinse them, salt them again & add to the umeboshi in your pickling container. I usually dry my umeboshi for a few days, after they have pickled for at least a couple of months, & then return them to the ume vinegar. They keep indefinitely if in a cool place or the fridge. You can dry the shiso leaves & crumble them as a condiment, too.
For umeshu, sterilize some large jars (the dishwasher will do, & so will a good rinse with shochu or vodka). Soak the ume in cold water for a couple of hours or overnight & take out the calyx (? not sure what it’s called actually – the little black bit at the stem) from each with a skewer or toothpick. Dry off the ume & fill your jars between 1/3 to 1/2 full of them. Add rock sugar (I use a scant handful for a quart jar – you can always add more when you decant) (Patel Brothers & other South Asian shops have rock sugar; the smaller crystals are fine & so are the big lumps). Most recipes call for adding the sugar & ume in layers, but it makes exactly no difference that I can tell. Fill the bottle with shochu or vodka (not rotgut, but need not be top quality). Put the lid on tightly & shake it up once a day for a couple of days, until the sugar dissolves. Store for six months to a year (a year is much better), & decant. You can re-use the ume for another batch, but the used ones are less flavorful, so adjust the amount accordingly (about double the proportion). If you have ume that are intact & look generally good, but have the odd tiny black spot or otherwise are not ideal for umeboshi, they will still make good umeshu.
Additional choices if you have any extras: infuse in rice vinegar or shoyu for a couple of months, or infuse in miso for at least a month with some rock sugar or even Sugar in the Raw. Miso flavored with ume is great on noodles & as a glaze.