Does Miso Go Bad?

Does Miso go bad or not? How do you tell if Miso has gone bad and is it still good to eat? Here's a guide with all the answers, including storage tips.

Maybe you’ve just bought a whole bunch of miso on offer, and now you’re wondering how you should store it.

Or perhaps you went on a health kick months ago, and now you’re worried that your open miso has gone bad.

Maybe you are wondering, can miso go bad? How long will it last? And many similar questions may be troubling you.

The good news is that miso is an ingredient and a kind of preservative. It has a long shelf life, provided you store it in decent conditions.

Let’s find out the best way to store miso, its shelf life, and signs of spoilage.

Related:Does Soy Sauce Go Bad?Does Soy Milk Go Bad?Does Tofu Go Bad?

What’s Miso?


Soybeans are fermented with koji and salt to prepare miso. Koji is a traditional ingredient in Japan.

Miso is very salty and tangy. It looks like a paste and adds flavor to dishes. Add it to your salad dressing, marinades, baked tofu, or vegetable dishes.

You can find a variety of miso in the market. It is available in different colors, too!

How To Know If Miso Has Gone Bad

miso products at japanese store

Miso does not get spoiled easily. But its quality may reduce slightly over a long period. If you want to know whether it is spoiled or not, look for signs like:

  • mold growth
  • discoloration
  • odd smell
  • change in taste

The tricky part is that the paste is fermented, so it can be difficult to differentiate between usable and spoiled miso.

How To Store Miso

miso soup
  • You can keep an unopened pack of miso in a cool place and away from heat sources and light. So the pantry and kitchen cabinet are the best places for it.
  • Don’t place it next to the stove. Temperature changes can alter miso’s taste.
  • After opening the pack, make it a point to seal it tightly after use.
  • You do not need to keep unopened packages of miso in the fridge.
  • After opening a packet of miso, let it remain in your fridge whenever you are not using it because that is the most suitable place for it. Low temperatures help miso to retain its quality.
  • But if the instructions on the package suggest that you do not need to refrigerate it after opening it, then just leave it in your pantry.
  • Use clean spoons to take out miso paste from the package to avoid microbial contamination.
  • You can keep opened or unopened miso in your freezer to retain its flavor and freshness. Store it at a temperature of 25°F to -5°F.

How Long Miso Lasts

miso paste

Thanks to the fermentation process used to create miso, it lasts for a while. There is no need for a best-before date, so sometimes you may not find any such date on the label.

Your unopened miso may retain its best quality for a few months after that date. In case the date of production is mentioned, you can assume that you can enjoy good quality miso for a year or more from that date.

After that, the paste may not get spoiled, but its quality may decrease and not be as tasty as before. It is because the process of fermentation continues slowly.

Miso can last approximately 3-6 months after the best-before date as long as it’s kept in the refrigerator (unless the packaging says otherwise).

One last thing: The shelf life of light-colored miso is shorter compared to dark-colored miso. So opt for the latter if you want your miso to last!

The Bottom Line On Miso

Miso contains salt, is fermented, and is a preservative, so its shelf life is long. If you keep it in a tightly sealed container in the fridge, there are fewer chances of miso going bad.

The good thing is that it can still be used past the expiration date!

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Alisa Shimoyama

Alisa eats her way around the world on her travels and likes to have good food ready and waiting for her when she gets back.