How Long Does Miso Soup Last?

Miso soup is a beloved dish all around Japan and is equally famous in many parts of the world too. It is very easy to make and is considered to be an excellent comfort food. 

But how long does miso soup last? Miso soup can last 2-3 days in the fridge. However, you should consume the soup within the same day for maximum flavor. While miso soup can be reheated easily, there might be some flavor differences in fresh vs stored miso soup.

Read below to learn more about miso soup, how it’s made, how to store it, and, how long it can last in the fridge or freezer!

What Is Miso Soup?

Miso soup is a simple combination of fish broth (dashi), miso paste, and a range of different vegetables. What makes this soup so popular is how versatile it is. There are literally dozens of ways to prepare miso soup!

The two main ingredients in this soup are miso paste and dashi. Miso paste is made from fermented soybeans and barley or rice malt.

Since it is fermented, miso paste provides a very mature and strong flavor that can be salty and umami-laden.

On the other hand, dashi is simply an umbrella term for stocks and is the fundamental ingredient in miso soup, noodle soup, clear broth soup, and more. 

Before we explain how to maximize the storage life of miso soup, we must first look at how it’s made – which will also highlight a few important tips on how to store it properly.

Here is how you can make miso soup at home:

You will need:

• 20g Kombu
• 3 cups dried bonito flakes
• 2-3 tbsp miso paste
• Tofu
• Green onions (garnish)
• Wakame (garnish) 

Instructions: 

1. Clean the kombu using a damp towel and then soak it in 4 cups of water for at least 4 hours or overnight. 
2. Add the kombu dashi into a saucepan and heat the water. Before the water boils, remove the kombu and then add in the bonito flakes. You can skip the bonito flakes if you are going for a vegan miso soup!
3. Bring the water to a boil and then turn down the heat and steep the flakes for about 10 minutes. 
4. Once steeped, filter the broth using a fine-mesh sieve and use the back of the spoon to squeeze out excess liquid from the flakes collected in the sieve. This broth is going to be the foundation for all types of miso soups. You can use it as it is or continue combining more ingredients for an even deeper flavor!
5. As per your preference, slice either hard or soft tofu into small cubes and set them aside.
6. Heat the prepared dashi again and put the miso paste into a ladle. Slightly dunk the ladle with the paste into the broth and use chopsticks or a spoon to agitate the paste. This will help it dissolve in the broth.
7. Now turn the heat down and add the tofu. Once the tofu is adequately warm, turn off the heat completely. Add a few green onions and wakame as garnish and serve!

That’s it! Miso soup is incredibly easy to make and requires very few ingredients which is one of the reasons why it is easy to store for later as well.

For example, the broth made during step 4 above can be stored individually for up to 3-4 days in the fridge and can even be frozen for up to 6-8 months! 

Also, there is a common misconception people have regarding using miso paste. 

You might think that since miso paste is fermented and already highly salted, its antimicrobial properties will transfer into the soup too? Right? Not exactly. 

It is true that, individually, miso paste is resistant to bacterial growth because of how it is prepared. But once it is mixed with other ingredients and exposed to water and heat, the soup will not be impervious to spoilage. 

The reason for this is quite simple: since miso soup does not contain the same concentration of salt and has a small ratio of fermented ingredients, bacteria can easily overpower the discrete ingredients and thrive, especially at room temperatures. 

However, there are a few things that you can do to slow this process.

How To Store Miso Soup

As mentioned above, the simple broth made from kombu and bonito flakes can last a few days in the fridge and a few months in the freezer.

However, once you mix miso paste and the other ingredients into the broth you will have to be more careful before consuming it.

It may be better to freeze each ingredient individually. Read our article Can You Freeze Miso Paste? for more information.

Since miso soup is so varied it can be difficult to determine the shelf life of each variation of the soup, but as a general rule of thumb, do not store miso soup for more than 2-3 days in the fridge and try to consume it the same day for maximum flavor.

This is true for both homemade, store-bought, and restaurant leftover miso soups!

Furthermore, if you do plan to store the soup for later, we highly recommend removing the garnish before storage and adding fresh wakame and green onions for a better flavor when reheating the soup.

Storage Instructions

Move the soup into an airtight container and store it at the back of the fridge at 40F. Try to consume the soup within 48 hours for the bests results. 

If you have ordered it from a restaurant, you can store the soup in the container it came in.

Alternatively, you can also just put a cling wrap over your soup bowl for more convenience, but please try to store the soup from other strong-smelling food like garlic.

Can You Freeze Miso Soup?

Miso soup can be frozen just like any other broth-based food. The trick here is to store the soup within 2 hours of preparing or ordering it. This way, you can minimize bacterial growth and potentially also increase the shelf life of the soup. 

Please keep in mind that you may have to remove some garnishes from the soup before freezing it. Be vigilant when freezing clam, tofu, or other meat-based miso soups as they might be more susceptible to spoilage. 

Move any leftovers into an airtight container and then store the soup in the freezer at 0F. This way, the soup should remain fresh for up to 3-4 months! 

To thaw it, simply microwave it or let it melt in a saucepan at low heat. Never let miso soup defrost at room temperature because it may spoil it!

Signs Of Spoilage

Here are some common signs of spoilage for all types of miso soups:

Strong Odor

This is the first thing that you should look out for when inspecting stored miso soup.

If there is a strong fishy odor, then that may indicate that the soup has gone bad. Sure, miso soup is made from bonito flakes and may inherently have a fishy aroma. 

However, bad miso soup just smells different – in a bad way. It will have an off-putting odor that should be very easy to detect.

Discoloration

Miso soup that has discolored or has a hint of green or white should be discarded immediately. While miso paste may go through minor changes and change color shades. Miso soup should never have any discoloration!

Sour Flavor

Even if you don’t notice the visual cues, there is a definitive way to figure out the quality of the soup: have a small taste of it.

If the soup tastes sour or mildly bitter then just spit it out, gargle with clean water and discard the soup.

Miso soup will never have any flavor changes! It might have less of an impactful flavor after storing but will never taste “different.”

Related Questions

Miso soup is incredibly easy to make and store – and if you do it right, the soup will easily last a while before it goes bad! 

Now that you know how to store miso soup, here are some related questions:

Does heating miso soup make it safe to eat?

No. Compromised miso soup is always unsalvageable and should be fully discarded. Any attempts to consume reheated and spoiled soup may be very dangerous. 

Even if you get rid of bacteria while heating the soup, the soup will still be contaminated because of the toxins released by the bacteria – which are equally harmful. 

Can you mix stored miso soup with fresh broth?

Yes. As long as the previously made broth was stored correctly, you can mix it with a fresh batch of miso soup.

However, mixing restaurant broth and homemade broth may not be a good idea because of the flavor discrepancies. 

For the best flavor, always try to make fresh miso soup and limit the quantity and serving size so that there are no leftovers. 

Can reheated miso soup be frozen?

No. Once you have reheated pre-stored miso soup you should consume all of it the same day.

The cycle of heating, freezing, then reheating can compromise the quality of the soup which may also make the soup susceptible to bacterial growth. 

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