Can It Go Bad?

Product storage and expiration info.

Can Miso Go Bad?

Can miso go bad? Technically, miso has already gone bad because this is a type of fermented soybean paste. Miso is a highly nutritious food that’s often used in Asian cooking. It can add depth and flavor to soups, stews, and salad dressing. It is also used as a seasoning for dips and sauces!  Since miso has a lot of uses, it makes sense to keep this product in stock. But what about its shelf life? Can miso go bad?

Can Miso Go Bad?

Although miso has a reasonable shelf life, it won’t keep forever. Miso has a limited shelf life and will go bad at some point. This is the reason why proper storage is important when keeping extra miso at home. The good news is, you can extend the shelf life of miso!

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On top of that, miso contains natural preservatives that actively inhibit the growth of bad bacteria and mold. But still, you have to store the product properly because miso isn’t impervious to spoilage at all. This product is often sold in sealed packaging to minimize air exposure. Air exposure is the enemy here. It can inhibit mold growth and dry out the product. You have to keep the miso tightly sealed after every use to extend its shelf life!

Signs that Miso Has Gone Bad

It’s hard to tell if miso has gone bad or is about to spoil because fermented products tend to give off a pungent aroma even when they’re still unspoiled. Still, miso will emit a distinct aroma when it is no longer safe to eat.

Since miso stays moist during storage, there is an increased risk of mold growth. So one of the first things you need to check is a moldy film that develops on top of the product. If there is a presence of mold, toss the miso in the trash. If the product has developed an off-color or there were changes in its appearance, discard the product.

How to Store Miso?

The best way to store miso is to keep it in the refrigerator. As with all types of fermented products, miso will continue to ferment because it contains probiotics. Essentially, this product is “alive” because it contains millions of good bacteria. You can tell that your miso is alive when it starts producing gas while in storage. The plastic container would puff up due to gas build up.

Since this product is “alive,” it is sensitive to temperature changes. The probiotics must be preserved during storage so you can maximize the nutritional value of this product. You can use the miso’s original packaging to store the product, no added prep needed.

Just chill the product at the back of the fridge and you’re done. You can also transfer the product in an airtight container, just make sure the lid is tightly sealed after every use for optimal quality and flavor. When kept in the refrigerator, miso will stay fresh for 18 months or so.

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Can You Freeze Miso?

Yes, you can freeze miso for long-term storage. Freezing won’t kill the probiotics within the product. The chilly temps will cause the friendly microbes to go dormant. We do suggest dividing the product into manageable portions so you do not have to defrost and re-freeze the rest of your supply.

You can use small resealable plastic bags or ice trays to store miso in the freezer. If you’re using an ice cube tray, just spoon a small amount of the product in the container and stick in the freezer. Leave the miso to freeze solid for 2 hours.

Then, take the miso out of the freezer, pop all the cubed miso carefully then place them in an airtight, freezer-safe container. Write the storage date then stick in the freezer again. When kept in the freezer, miso will keep indefinitely. However, we recommend consuming your supply as soon as possible for optimal flavor.


Miso adds a wonderful flavor to everyday dishes so go ahead, buy more than you need and just keep the rest in the fridge or freezer for future recipes. Can miso go bad? Yes, this product won’t keep forever but it boasts of a long shelf life.

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