Ingredients for 1kg of fresh plums

Fresh ripe plums (完熟梅 / Kanjuku ume) 1㎏
Salt (塩/ Shio) 170g
White rum (ホワイトリカー / Howaito rikāh) 50ml
Akashiso (赤しそ / Akashiso) 100g
Salt (塩/ Shio) 20g

Note: “White liquor” is white rum sold in Japan. Outside of Japan, look for white rum or try making this recipe with vodka.

<How to Make>
umeboshi preparation① Brine the plums. Use a mixing bowl large enough to hold a generous amount of water and the plums. Fill the bowl with water, add the plums and rinse them gently under running water. Be careful not to damage them. Drain the water off and use a paper towel to dry the plums. Use a bamboo skewer or toothpick to remove the little round bit of material (narikuchi [なり口]) where the stem was attached. This will help to prevent the development of mold.
umeboshi salt② Dip each of the plums in white rum, add the salt, making sure to coat the plums completely, and then divide the plums into two even amounts. Place each half of the plums into a medium-size resealable plastic bag, remove the air, and seal.
umeboshi zip③ Place the bags one on top of the other into a tray with some depth. Switch the positions of the bags once a day until umezu (梅酢) starts to come out. (You could also use a bottle to make umeboshi. If you do, first disinfect the bottle by wiping the inside with a paper towel dampened with white rum (vodka is OK, too). Next, add a layer of plums, then salt, then another layer of plums, and so on, ending with salt on top. Place a weight equal to the weight of the plums and salt on top of the plums and salt. The salt will cause water to come out of the plums, but not immediately. To speed up the process, stir the plums once a day for the first three days. Set the bottle aside for 10 days to 2 weeks and then proceed to step 4.
akashiso preparation1④ Prepare the akashiso. Rinse the akashiso well and drain off the water. Sprinkle on 1/3 (about 5g) of the salt and knead the shiso. Rinse and repeat this process two more times. This will remove astringent elements from the taste of the shiso.
akashiso preparation 2⑤ Squeeze out as much of the liquid as possible from the shiso. Add 1tbsp of umezu to the shiso (This is not included in the ingredient list and you can use vinegar instead*.) This will cause the shiso to further redden and help to prevent spoilage once the plums and shiso are combined.
⑥ Add the akashiso to the bags with the plums and massage the bags to distribute the akashiso among the plums. The addition of shiso to the plums will produce the characteristic red color of umeboshi.
Sun-dry the plums. Around the end of July, when the rainy season finally ends, is the proper time for this. Check the weather forecast and choose a period when there will be 2-3 days of sunny weather. Remove the plums from the jar and place them on a bamboo or plastic basket with a fairly flat bottom (Do not use anything made of metal because it is likely to contain steel, which will rust.) Squeeze out the umezu from the akashiso and place it on the basket, too. Dry the plums and akashiso under the sun for 4-5 hours a day. Bring the basket inside at night. Give the plums a quick dip in umezu and put them back on the basket. This will help to produce soft, succulent umeboshi. Perform the process described above for 2-3 days, then return the plums and shiso to the resealable bags and let them age for at least another month. The plums – umeboshi – can be eaten once the sun-drying has been completed, but they will be very sour. Letting them age for at least a month will soften the taste.

* The amount of time to age umeboshi is a matter of preference. Letting umeboshi rest for 2-3 years, for example, is said to take the edge off of both the saltiness and sourness. You may find it interesting to set some of your umeboshi batches aside each year to see how aging changes their flavor.

Recipe Developed by: Machiko Tateno

Plums are from Wakayama.