Made with fluffy Japanese rice, chopped pickled plums, and sesame seeds, these Plum Rice Balls are THE BEST THING for a picnic and potluck! It‘s hard not to fall in love with the savory, tangy, and nutty flavor of these onigiri.
Mr. JOC and I started watching season 2 of the popular Netflix® show – Midnight Diner: Tokyo Stories so that we can re-create the recipes from the series. In Episode 3, an old man named Umejii went into the diner and requested for pickled plums. When the master handed him a plate, he ate 10 of these plums straight up! My mouth immediately watered and my face scrunched up, literally like a sour plum.
Then I glanced over at Mr. JOC sitting next to me. His face plain and he didn’t seem to show any sort of reactions. This simple scene was able to ignite such a strong response in me, but not my husband who obviously didn’t grow up eating ume plum. Isn’t it interesting how our mind reacts to the food memory we have?
Today I’m sharing the Plum Rice Ball (小梅のおにぎり) recipe that Umejii enjoyed eating in the episode. It would be fun if I could see your face scrunch reading about pickled plum in this post.
What is Plum Rice Ball?
In case you haven’t seen the show, the Plum Rice Ball is a triangle-shaped rice ball made of steamed white rice, chopped pickled plums, and sesame seeds, and cloaked in a sheet of dried nori seaweed.
Japanese Pickled Plum – Umeboshi
Umeboshi (梅干し) is a savory Japanese pickled ume plum and it’s eaten as a condiment or accompaniment for a bowl of rice, similar to tsukemono pickles or furikake rice seasoning.
Ume plums are salted, flavored with red shiso leaves, and then dried under the sun to make umeboshi. The ultimate companion for a bowl of plain steamed rice.
In general, there are two types of umeboshi made with different ume plums. The regular, bigger wrinkly pickled plum is called Umeboshi, and the smaller and plump umeboshi is called Ko Ume (小梅).
The pickled plums used in the Midnight Diner episode are Ko Ume. They are firm, tangy, salty, and come in a bright red color. You can often find these small red ume pickle in the middle of white steamed rice in a bento box. We call it “Hinomru Bento” (日の丸弁当), which represents Hinomaru (meaning “circle of the sun” representing a Japanese flag 🇯🇵).
Where to Find Ko Ume
I remember I used to see packages of small umeboshi at Japanese grocery stores, but when I decided to make the rice balls and looked for one, I couldn’t find it. I went to different Japanese grocery stores and they seem to disappear from the shelves. That’s strange, I thought. It shouldn’t be that popular that all the stores are sold out.
So I asked one of the staff when they would restock these pickles. And the lady said they can’t be imported any more due to the artificial red coloring used for the plums. It’s really unfortunate to see ingredient(s) that is not quite necessary being added to the foods that we feed our bodies.
In the end, I had asked my mother in Japan to send me a package of Ko Ume so I could make the recipe as close as what you see in the show. For your own enjoyment, please use the regular umeboshi that is healthier. The red color of the plums should come from only natural red shiso leaves, not additional artificial coloring. You will still yield the same flavors and faintly pinkish rice balls. The only difference would be the texture as regular umeboshi does not have the crisp crunch that Ko Ume is known for.
* I found out Nihon Ichiban sells these small crunchy Kari Kari Ume and Low Sodium Kari Kari Ume online. They ship internationally.
Tips on Making A Rice Ball
- Use Japanese short-grain rice – I can’t stress enough that you really need to use Japanese short-grain rice to make rice balls. Short-grain rice naturally sticks to each other once they are cooked. All you need to do is to gently press to keep all grains together.
- Wet your hands – It might sound silly to even mention it, but don’t touch cooked rice with bare hands. Rice just sticks to your hands and everywhere. Make sure that your hands are moist and that salt is applied to your hands to keep the rice balls safe at room temperature.
- Make the triangle roof – Holding a ball of rice in your left hand and making a 90-degree “roof” with your right index and middle fingers and your right palm, mold the rice into a triangle shape with gentle pressure.
- Rotate the rice ball – Press gently into a triangle rice ball shape while you rotate the rice ball so each corner gets a sharp 90-degree edge.
- Keep your rice ball at room temperature – With salt and sour pickles, the rice balls kept at cooler room temperature (61-68ºF, 16-20ºC) are safe to consume even after 6-8 hours later. Rice gets hard when kept in the refrigerator. If you really have to store in the refrigerator, wrap the rice balls with a thick towel to keep them cool, not too cold.
How to Serve Plum Rice Ball
In the “Midnight Diner: Tokyo Stories”, the old man Umejii enjoyed the plum rice balls on its own. However, you can pack them in your bento lunch box or serve them as an after-school or midnight snack. They are fabulous with a cup of green tea!
Other Popular Rice Balls (Onigiri) You’ll love:
- Cherry Blossom Rice Balls
- Tenmusu (Shrimp Tempura Rice Ball)
- Miso Yaki Onigiri
- Bulgogi Onigirazu
- Spam Onigirazu
Wish to learn more about Japanese cooking? Sign up for our free newsletter to receive cooking tips & recipe updates! And stay in touch with me on Facebook, Pinterest, YouTube, and Instagram.
Plum Rice Ball
Ingredients
- 4⅓ cups cooked Japanese short-grain rice (make using 1½ cups or 2 rice cooker cups of uncooked rice)
- 3.5 oz pickled plums (ko ume) (use the small-sized variety with a firm, crunchy texture)
- 2 Tbsp toasted white sesame seeds
- 1 tsp Diamond Crystal kosher salt
- 3 sheets nori (dried laver seaweed) (Cut the nori sheets in thirds)
Instructions
- Gather all the ingredients. For the cooked rice, please note that 1½ cups (300 g, 2 rice cooker cups) of uncooked Japanese short-grain rice yield 4⅓ cups (660 g) of cooked rice. See how to cook short-grain rice with a rice cooker, pot over the stove, Instant Pot, or donabe.
- Remove and discard the seeds from 3.5 oz pickled plums (ko ume).
- Mince the plums with a sharp knife.
- Add the chopped pickled plums and 2 Tbsp toasted white sesame seeds to 4⅓ cups cooked Japanese short-grain rice.
- With a rice paddle, mix well together using a cutting motion. Don’t “stir“ the rice and make it mushy. Roughly divide the rice into 6 or 8 equal portions.
To Shape the Rice Balls
- Prepare a bowl of water and a bowl of 1 tsp Diamond Crystal kosher salt. Wet both hands and then dip 2 fingertips in the salt and spread between your palms.
- Scoop the rice onto your palm. Gently press and form the rice into a triangle. I use three fingers (thumb, index finger, middle finger) to make a triangle corner. Tip: For step-by-step photos and instructions on how to shape the rice balls using your hands, an onigiri mold, or plastic wrap, see my Onigiri recipe.
- When you press, your hands should be just firm enough so the rice ball doesn‘t fall apart. You don‘t want to squeeze the rice too tight.
- Wrap the rice balls with strips cut from 3 sheets nori (dried laver seaweed). Enjoy!
How long can you safely leave the onigiri at room temperature after making?
Hello Eric, Thank you for trying Nami’s recipe!
With salt and sour pickles, the rice balls can be safely consumed for up to 8 hours if kept at a cooler room temperature (61-68ºF, 16-20ºC). However, the safety also depends on humidity and weather conditions, so we don’t recommend leaving them out for too long. Please keep them cool and enjoy them as soon as possible!