miso paste

Miso Paste Shelf Life: Can It Go Bad?

So, you’ve heard about miso paste that goes well for salad dressing. Miso is vegetarian friendly, and you want to give it a try.

Or, you’re about to experiment with Japanese cooking, and your first trial goes to miso soup recipe. To make this simple but tasty dish, of course, you need miso paste.

Either way, you’re new about miso and need to know more about this soybean paste. Since you won’t use it regularly, you’re wondering: does miso paste go bad? How about miso storage? Does miso need refrigeration?

In this article, we share some basic knowledge on miso paste, its shelf life, storage methods, and how to know if miso goes off. If this is something you’re looking for, read on!

What Is Miso?

Miso is another staple ingredient in Japanese and Korean kitchen. It’s a base for many dishes, from the famous miso soup, ramen, hot pot (nabe), and many more.

Miso (also known as soybean paste) is made by fermenting a mixture of soybean, grain (rice, barley), salt, and koji– the same mold that’s also used to make sake and soy sauce.

Similar to other fermented foods, miso is known as nutritious food and a good source of probiotics – the beneficial microorganisms for your body.

In Japan, numerous different miso variants are available across the country. The differences lie in the ingredients, length of fermentation, preparation methods, and so on.

The appearance, flavor, and taste widely differ. Miso is generally known for its umami taste, a combination of salty, sweet, and savory flavor.

White miso (Shiro miso) and red miso (aka miso) are two of the most common miso available in the international market. Red miso is characterized by stronger and salty taste, while white miso is lighter and sweet. Next to that, if you come across mixed miso (awase miso), this one is just a mix between the other two.

That’s the basics of miso, jump into the FAQ section at the end of this article to find more nitty-gritty of miso. 

How To Store Miso

Unopened packs of miso paste can be kept in a cool, dry place, away from sources of lights and heat. Your pantry or kitchen cupboard is the perfect spot.  Sometimes, you can find miso paste at a refrigerated shelf in the store. For this kind of product, it needs to be kept refrigerated at all times. 

After opening, whether to keep them refrigerated or not, the instructions vary among producers due to different product characteristics.

Most producers suggest keeping the paste refrigerated, while some claim that the paste is pretty stable at room temperature. Hence, follow the manufacturer’s instructions. 

Either way, don’t forget to seal the package tightly when not in use. Always use clean utensils to scoop out this healthy stuff to prevent contamination.

If the package is not resealable, transfer the paste into a jar or an airtight container. Cover the surface with a parchment paper or plastic wrap to reduce the exposure to air. This treatment is useful to prevent oxidation that will degrade the flavor and taste.

Can You Freeze Miso?

Yes, it is possible to freeze miso. According to Hikari Miso, miso paste can be kept in a freezer with a temperature higher than -5ºC or 25 ºF.

At this condition, miso won’t freeze, but the flavor and taste are best preserved. Consider dividing the paste into a small portion of the size that you usually need for one recipe. 

How Long Does Miso Last?

Miso generally lasts for a long time (some producers claimed to store their products for years!), particularly the variants with longer fermentation time. However, the flavor and taste will slowly dissipate over time. 

Miso comes with either “best before” or “best by” date printed on the package. This date is an indicator of quality rather than a safety date. It means that miso can be consumed beyond this date with expected changes in quality, as long as it doesn’t show any signs of spoilage.

As with other foods, after opening, it’s always best to finish the product immediately before the paste starts to lose its quality. Miso should be good for a few months to a year in the refrigerator. This estimate varies between brands.

ClassificationPantryRefrigerated in the fridge
Miso (unopened)1 year 
Miso (opened) 3 – 12 months

This table is a general guideline. Since miso differs significantly in terms of preparation methods and length of fermentation, it’s always best to follow the manufacturer’s instructions.

Miso paste may remain edible after these periods, but subtle changes in flavor and taste may occur.

How To Tell If Miso Goes Bad

Telling miso going bad might not be an easy task for some people since miso is a fermented product that has a strange smell in the first place. Let your senses be the judge.

If you notice any change in smell, color, or texture, you should be more cautious than the first time the package is opened. If you see any molds, let’s take the safe side and discard the products. Miso was indeed fermented with molds, but you never know if the molds you see now are from the same kind. 

When nothing looks suspicious, take a small amount of paste to taste. If you’re still satisfied with the taste, feel free to make it into miso soup or your favorite recipes. 


Where do you find miso?

With the rise of Japanese cuisine, miso has made its way into international markets. Sometimes miso paste is also labeled as “soybean paste.” You can find it either in the supermarket, a good food store, or an Asian grocery store. It’s also possible to find miso on online stores, such as Amazon.

Depending on the store, it can be in different sections. The standard sections of miso are on the international, Asian, oriental, Japanese, or Korean aisle. Sometimes, miso is placed on a vegetarian or healthy food shelf, next to tofu, tempeh, and vegan meat.

If you shop at an Asian store, miso paste is usually located among other condiments and sauces.

Is miso paste spicy?

Miso is generally known for its umami taste, a combination of salty, sweet, and savory flavors. The flavor and taste are ranging from light to intense, depending on the region, length of fermentation, and other factors.

Red miso is stronger and pungent in flavor. It’s not spicy as in chili spicy. However, in the Kanto Region of Japan, there is a miso variant named Nanban miso that’s infused with hot chili. But, this type of miso might not be sold outside Japan.

Does miso need to be cooked?

No, miso paste doesn’t need to be cooked. The most popular use of miso is probably for preparing miso soup (misoshiru). But, there are plenty of other ways to use this soybean paste. Miso is also great for your salad dressing, marinades, and as a dipping sauce.

Why does my miso turn darker after a while?

The darkening in miso during storage is a result of the Maillard reaction due to exposure to warm temperature. This doesn’t compromise the safety aspects of miso.

How long does miso soup last?

Miso soup can last for 3 to 4 days when kept refrigerated. If the soup smells and tastes bad, or looks suspicious before this period, better to toss it away and make a new batch.

Final Thoughts

Miso is another staple ingredient in the Japanese kitchen that boosts the savory and umami flavor. It is a shelf-stable item that can be kept for a long time.

Keeping miso in the refrigerator after opening is considered as a general practice. However, storage guidelines may differ among producers. Hence, always check the label. Although going bad is a rare occurrence, miso does degrade in quality.

Up next: Best Substitutes for Miso Paste

miso shelf life

*Photo by luknaja/depositphotos

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