More about onigiri: keeping them fresh and more

In a comment to my Onigiri Revisited post, Jennifer said:

I’ve made fresh onigiri a number of times and would love to be able to make it the night before and take into work with me the next day. How do I do that? (or am I out of luck?) The rice gets all hard and I’ve tried sprinkling water on it in the microwave, but then it falls apart. Suggestions? Do I need a special type of rice? How do I store it after it is made?

Onigiri really are better if made the morning of the day you're going to eat them. I remember my mom waking up very early in the morning to make onigiri when we had a school outing (which usually meant an obento lunch with onigiri).

That being said, you can make them the night before, but you need to take some measures. There are a few things you can do to have moist (but not wet) rice balls.

Tips for making moist-until-you-eat-them onigiri

  • Use Japanese medium-grain rice (uruchi-mai, or sushi rice) - other types of rice don't really stay moist enough. (Short grain mochi rice is a possibility, but they make for very glutinous and gooey rice balls.) See the Looking at rice post if you're not sure what rice is what.
  • Make sure you are making them with freshly cooked rice, that's still hot, not cooled. Don't make onigiri with room-temperature will not stick together well and will dry out fast. The cooked rice should be nicely moist and plump to start with.
  • Wrap them completely in plastic wrap before storing in the refrigerator. This keeps the moisture in and prevents the surface from drying out. (Wrapping them in nori would have a similar effect, but then the nori will turn out rather soggy. I prefer to wrap in plastic and bring the crispy nori along separately.) A typical refrigerator is as dry as a desert inside, so you have to protect the rice from that dry air.

Keeping onigiri fresh

Onigiri were developed as a portable meal. Salting the surface is not only done for flavor; the salt helps to preserve the freshness of the rice. So be sure not to skip the salt if you plan to eat the onigiri some time after you make them.

Traditional onigiri fillings tended to be salty had long keeping qualities. Umeboshi (pickled plum) in particular is purported to have antibacterial qualities, so were an ideal filling for rice balls that were to be carried for a long time by hot, sweaty travelers.

If it's only going to be a few hours until you eat the onigiri, AND you can keep them reasonably cool (in a dark place out of direct sunlight), AND you use enough salt on the surface, they can be kept at room temperature. If you think you'll be carrying them around for a very long time though, it's probably best to use umeboshi or another long keeping, salty filling, rather than something like tuna-mayo or Spam.

Nuke them

If you are bringing them somewhere where you have access to a microwave, you can also freeze them. Defrosting time depends on how many onigiri you have, how big they are, how powerful the microwave is, etc. but once you get the timing right you can get hot onigiri that taste like they were just made. Be sure to wrap them in microwave-ready plastic wrap in that case! I often make extra onigiri and tuck a few in the freezer as treats.

What to do with dried out onigiri?

If the surface has dried out a bit but the insides are still moist, you can turn them into yaki onigiri. But if they are further gone than that, you can turn them into ochazuke, rice with tea. Just heat up the onigiri in the microwave, or even better grill them a bit a la yaki onigiri to make them crispy, then proceed as described in the ochazuke recipe by pouring on hot tea with toppings. Delicious!

Filed under:  japanese rice onigiri how-to

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:) I often make onigiri for my school lunch, and was really frustrated when they turned out hard, dry and unpalatable. When I made them next, too much moisture caused sad soggy riceballs.

A good tip for keeping them nice and fresh is adding Sushi vinegar to the rice, which lets the rice maintain its soft fluffiness!

I would put them in a microwave for 45 seconds, then put it in the freezer to cool down for 1 or 5 mins, depending on your taste.

I have a question, I know its about the same thing, but the thing is, I'm going to make the sushi rice at night and then use them the next day to make onigiri in the morning. Does the rice spoil over night or do I have to microwave oven it as well?(if i do, how long?)
Will it still taste nice and able to be used to make onigiri?
I hpe that you will be able to reply me.


Here is what I do in that case, in order of preference:

  • if you have a rice cooker with a timer, wash the rice and put in the cooker with water and set the timer so that the rice will finish cooking in the morning when you're ready to make onigiri. (this is what I actually do most of the time when I make onigiri for bentos.)
  • else, cook the rice, take it out warm, cover with plastic wrap, let cool down and put in the fridge. In the morning nuke for a minute or two (depending on how much rice there is) to revive it.
  • else, if you have a rice cooker with a 'keep warm' function you can use that...but that would be my least favorite choice.

- else, if you have a rice cooker with a 'keep warm' function you can use that...but that would be my least favorite choice.[/quote]

what is wrong with 'keep warm' function? does it make rice overcooked and dry?

I think it's because the keep warm function keeps the rice at a temperature ideal to the proliferation of bacteria.

I made a batch of smoked salmon onigiri (YUM!) a couple hours ago, and have since been online researching how I can keep them fresh for the boyfriend's lunch tomorrow (yes, I know I should have thought of this beforehand..).

One suggestion I got was to wrap them individually in Glad-Wrap (or plastic film) and store them in a plastic container in the fridge. This way, the rice is supposed to stay moist and lovely, albeit a little bit more sold than it would have been, freshly made.

I'm trying it out tonight, so wish me luck! I'll tell you how it goes tomorrow ^^.

Happy onigiri-ing!


My gramma (from Kumamoto) told me to wrap musubi in foil to keep them from getting soggy. So for an anime convention (the food cost so much there it was frightening) I made the musubi the night before (nothing fancy just with ume) and wrapped the rice balls in aluminum foil, packing the nori separately. My husband took for lunch the leftover musubi (which we kept in the foil) for two days after the convention was over and the musubi remained firm, unsoggy, and never soured, even on the third day after they were made. I don't know if that was a fluke but at this time I am a firm believer in using foil to keep my musubi fresh! Arigatou gozaimasu Obachan!

I would say the onigiri stayed fresh because of a few factors: you probably let them cool off a bit before wrapping; umeboshi is a great filling for onigiri that has to keep for some time (it acts as a preservative); and the foil may have helped also by allowing the onigiri to 'breathe' a bit. Obaachans are great sources of wisdom!

Actually Foil is the best barrier to gases and liquids in food packaging.

I know to reheat chinese takeout rice, you can lightly sprinkle with water and then microwave a few seconds and it makes it very fluffy and wonderful again! I'm sure the same thing would work on a slightly dried out onigiri.

I can't wait to make my own Onigiri! I'm starving for some! X_X

OK, so I just returned from a trip to Japan where I sampled the Onigiri at every conbini (convenience store) I came across. I noted the shelf-life for most of the Onigiri was about three days. This was true even when the fillings were either fish or meat.

When I got home I was fortunate enough to find nori wrappers encased in two layers of plastic-- just like 7-11 in Japan uses (this keeps the nori from touching the rice until you are ready to eat). Somehow, however, 7-11 is able to keep meat-filled Onigiri "fresh" in their display cases for three days. How do they keep their rice from drying out? I suspect they must add something to the rice during the cooking process (baking soda, salt, vinegar, ???).

I too would like to make Onigiri that last for 3 days in the fridge. If anyone has suggestions, I'm game!


i just started making onigiri and i am having some difficulty. I bought medium grain rice and followed the instructions of some youtube videos i saw on making onigiri. i washed and soaked the rice, cooked it w/the right amt of water, wiped my hands w/salt water, shape rice into triangles, etc. (and almost burned myself)...but not long after i made the onigiri (say 30min-1hr), it started to fall apart! did i do something wrong?? please help!!

If you put a filling inside, I am guessing it was either too wet or too oily. You may want to look at the other onigiri articles on this site and the sister site Just Bento for more help.

Thank everyone for all the tips! I made some for the fist time last night following the second way!! Thanks!! :) It was fun and not as hard as I imagined!

I let my cool completely before wrapping them in plastic to give to my family.
The ones I took to work were just stored in Tupperware. I imagine like storing all rice, it just depends on the air. If cold air touches rice direfctly it will dry it out! If you dont let it cool before wrapping it in the plastic wrap and putting it in the fridge, it will condense too much! (you could try the freezer where it will just begin to freeze rather than condense!

Its the same principle with baking cakes, which I love to do! Good luck everyone!

I was Wondering if I could make the onigiri then wrap them in plastic wrap and pop them in the fridge for possibly 9 days, would it still be ok?

Hi! I would like to make a tuna-mayo onigiri. I am planning to make it early morning, pack it inside a lunchbox and eat it for lunch. I don’t have the resources to refrigerate or microwave it. Will it taste ok?? I’m afraid the filling will spoil and the nori wrap will get soggy. Help pleaseeeeeee THAAAANKS!!! I’ll probably make it about 7am then eat it at 12.30noon? Will it still taste nice???

Hope you can reply as soon as possible….THAAANKS <3 I am planning to make one tomorrowwwww:D

I have learned so much from your website, and it has truly enriched my life and added some wonderful new flavors to my every-day routines.

I wanted to add a quick tip for reheating your Onigirii. I typically have to store them overnight if I want them for lunch, and if I find that they have dried out a bit in addition to being cool when I get ready to eat them, I've found a great way to reheat them. I drape a damp (not dripping) paper towel directly on the top of the Onigiri and pop them into the microwave. Then, set the microwave to half power, and I set it for about 45seconds for one, and just over a minute for two.

Use the microwave's half-power so that it heats delicately. The damp paper towel adds moistness back to them, but it also causes the microwave to heat them up much faster, so be careful that you don't leave them in there too long.

This procedure results in beautifully moist, warm Onigiri that are just as good as when they were first made!!!