
A lot of the rice balls on convenience store shelves include oil, but it’s not to make them taste better.
Among the many wonderful things at Japanese convenience stores, perhaps the most wonderful of all are the rice balls, or onigiri, as they’re called in Japanese. Tasty, reasonably priced, and relatively healthy, you’ll find convenience store onigiri with all sort of fillings, such as salmon, chicken, and plum.
But there’s one ingredient present in a lot of convenience store onigiri that even most Japanese shoppers aren’t especially conscious of: oil.
▼ 油 = oil
Specifically, it’s vegetable oil that many convenience store onigiri have. This isn’t a new development, but since it’s something a lot of people aren’t aware of, every couple of years it gets some people in a stir when someone notices/points out “oil” on a convenience store ingredient list, like in this tweet posted this week with a photo of a plain slated rice onigiri from convenience store chain Family Mart.
▼ “Make it with just rice and salt,” the poster pleads.
米と塩だけでつくってくれよ pic.twitter.com/Lqnk6vWVye
— 健康最高 (@yrzXlZARNuPcPsv) March 26, 2023
You might assume that the oil is added as a cheap but unhealthy way to make convenience store onigiri taste better, but the truth is actually more complicated, with no fewer than three reasons for the oil. The first is texture. Adding oil to the rice before it’s cooked creates a coating for the individual grains, so that even though they’re pressed together and retain their rice ball form, there’s enough space between them for a light, fluffy consistency.
“But wait, what about homemade onigiri? Those don’t have oil in them,” you might be asking. That’s true, but unlike onigiri made at home and then eaten soon after, convenience store onigiri are made at a factory, then shipped to the chain’s branches and stocked on refrigerated shelves until they’re purchased. Without oil, the passage of time and low temperature would make the rice clumpy and hard.
The second reason has to do with how convenience store onigiri are made. Rather than being pressed by hand, they’re made with a mechanical press. The oil helps prevent rice from sticking to the machinery, which keeps the shape of the onigiri nice and consistent.
And finally, the oil in convenience store onigiri is there because of how the rice balls are packaged. They have to be wrapped in something, usually plastic, and just like how the oil keeps the grains from sticking too closely to each other, it also keeps the onigiri from sticking to the inside of its packaging, so it can be removed without inadvertently tearing off a piece of the rice ball.
▼ If this onigiri was poorly formed or sticking to its package it might spill its beefy filling before you can bite into it.
All that said, not every convenience store rice ball is made with oil. It seems like the ingredient is more common with onigiri that don’t have a nori (seaweed) wrapping.
▼ This sardine and sansho spice onigiri has oil in its ingredient list…
▼ …but this salmon onigiri, with a nori wrapper, doesn’t…
▼ …and neither does this seaweed-equipped salmon onigiri.
And thankfully, even when convenience store onigiri are cooked with oil, it’s not like the rice was boiled in a 100-percent pot of the stuff. The salt onigiri from 7-Eleven pictured at the start of this article has a total of 0.9 grams of fat, and the onigiri pictured in the tweet, from rival chain Family Mart, has only slightly more fat, 1.1 grams. So even if convenience store onigiri aren’t always entirely oil-free, they’re still a pretty healthy snack choice, so the main thing to worry about is whether or not you can open the wrapper the right way.
Source: Hachima Kiko, Shukan Josei Prime
Photos ©SoraNews24
● Want to hear about SoraNews24’s latest articles as soon as they’re published? Follow us on Facebook and Twitter!
Follow Casey on Twitter, where he misses the Kaizoku Musubi rice balls from Iwakuni Station.








Which convenience store onigiri rice balls are the most popular? Survey reveals surprising results
Survey ranks convenience store rice balls – salmon, sea-dwelling poultry & plants steal the show
Are high-end convenience store rice balls really packed with more ingredients?
Are Family Mart’s new “exquisite” rice balls worth the high price tag?
Japanese convenience store issues rice ball recall, foodies would’ve loved to eat them anyway
Studio Ghibli releases the My Neighbour Totoro tea caddy, with a magical self-closing lid
Create a tiny Ghibli anime world on your bookshelf with new miniature papercraft art kits
A secluded British mansion in Chiba is a hidden holy land for afternoon tea lovers
Japan now has a “for foreign tourists only” Mt. Fuji sightseeing train[Video]
Fake police phone scam also highlights dumb stereotype about how foreigners speak Japanese[Video]
Starbucks Japan releases new My Fruit³ Frappuccino at only 34 stores around the country
Nine amazing off-the-beaten-path cherry blossom spots in Japan for yaezakura and shidarezakura
Stunning central Japan wisteria festival is like a purple fantasy straight out of a Ghibli movie
Nephew receives SD card after his uncle passes away, finds treasure trove of gems from the past
Peach Coca-Cola coming to Japan in a world-first for the company
Japanese onsen egg maker from 100-yen store Daiso needs to be on your shopping list
Cherry blossoms begin blooming in Japan with record-early starts for sakura season
Tokyo government organizes food truck event to clear out delinquent/homeless teen gathering area
The next time you’re feeling stressed out, you could relax on a Pokémon Psyduck chair from Japan
Train station platform ramen store closes its doors on half a century of history in Tokyo
When will the cherry blossoms reach full bloom in Japan this year?[Forecast]
Studio Ghibli adds new Mother’s Day gift sets to its anime collection in Japan
Starbucks Japan unveils new sakura cherry blossom collection for hanami season 2026
Studio Ghibli releases Catbus pullback keychain that runs like the anime character
Nine great places to see spring flowers in Japan, as chosen by travelers (with almost no sakura)
Starbucks Japan releases first-ever Hinamatsuri Girls’ Day Frappuccino
Virtual idol Hatsune Miku redesigned with look that adds new elements and brings back old ones
Survey asks foreign tourists what bothered them in Japan, more than half gave same answer
Japan’s human washing machines will go on sale to general public, demos to be held in Tokyo
Starbucks Japan releases new drinkware and goods for Valentine’s Day
We deeply regret going into this tunnel on our walk in the mountains of Japan
Studio Ghibli releases Kodama forest spirits from Princess Mononoke to light up your home
Starbucks Japan releases new sakura goods and drinkware for cherry blossom season 2026
Japan’s newest Shinkansen has no seats…or passengers [Video]
Major Japanese hotel chain says reservations via overseas booking sites may not be valid
Put sesame oil in your coffee? Japanese maker says it’s the best way to start your day【Taste test】
No more using real katana for tourism activities, Japan’s National Police Agency says
Japan Railways recently revealed ramen-style rice balls in its convenience stores
Japanese convenience store packs a whole bento into an onigiri rice ball
Convenience store onigiri rice balls become even more expensive…but are they worth it?
In celebration of Onigiri Day, we compare rice balls from three different convenience stores
Which Japanese convenience store has the best plain onigiri rice balls?
Japanese convenience store’s newest rice ball filling: Nothing at all, and why we’re OK with that
Japanese convenience store showdown – Who’s got the best ikura rice balls?【Taste test】
The 10 best types of onigiri rice balls to try in Japan【Survey】
Should you warm up your convenience store onigiri rice balls in the microwave?【Taste test】
Which Japanese convenience store has the best salted onigiri rice balls?
Japanese convenience store releases a new bento sandwich, but is it better than a bento rice ball?
Weiner Onigiri: Japanese convenience store rice ball has a surprise in store for Mr Sato
The difference between onigiri rice balls in Tokyo and Osaka
As rumors swirl of 7-Eleven shorting customers on rice ball fillings, we check on their sujiko
It’s a Japanese boxed lunch in the palm of your hand with the new bento rice ball
Gyoza rice balls are here, and everyone agrees they look awesome, but are they? 【Taste Test】