Miso Soup Shelf Life: Does It Go Bad or Expire? How To Tell


Picture this, you’ve decided to try making miso soup for yourself, but you got a little over-excited and made way too much. Now that you’ve got too much soup on your hands, you might be asking yourself: does miso soup go bad?

Short Answer:

Yes, miso soup will eventually go off. Even though miso is long-lasting, the soup itself can only last a few days if stored correctly.

Miso soup is a delicious and healthy soup that should never go to waste, so it’s essential to understand its shelf life and storage needs.

In this article, we will tell you how to spot when your miso soup has gone bad and give you some tips on storing it to keep it fresh.

Ok, let’s dive in!

What Is Miso Soup Made Of?

image of eat miso soup

Miso is a soup that is one of the two main soup types in Japan, along with suimono. It dates back all the way to the 1500s!

This soup may be popular, but it’s not complicated.

The two main ingredients that go into miso soup are [*]:

1. Dashi

This is a family of stocks used throughout Japanese cuisine. It has a strong umami flavor.

It is commonly made using kombu, edible kelp, and shavings of katsuobushi, preserved fermented tuna.

2. Miso Paste

This is a specialized Japanese seasoning that is made from soy beans that have been fermented with salt and koji.

It has a very distinctive umami flavor. Since it is fermented, it has a funky smell and a very long shelf life compared to the soup.

The dashi is usually boiled first and used to cook the tofu and various vegetables. The miso is dissolved into it at the last minute before serving.

The beauty of cooking with miso paste is its indefinite shelf life.

This means you can buy a sachet of miso paste and keep it in the fridge for years without it going bad. 

This means you could make fresh miso soup whenever the craving hits without going to the shops.

Does Miso Soup Go Bad?

Miso soup will go off because it loses its preservative qualities once the miso paste has been mixed with the dashi and fresh ingredients.

Due to this, we need to know what to keep an eye out for if your miso soup has gone off. Let’s take a look at how good and bad miso soup compare.

Fresh miso soup will be:

1. Clear

Miso soup should be an even pale brown and relatively clear.

It should be the same even color and clarity throughout the whole soup.

2. Fermented smell

This can be tricky because miso naturally has a powerful odor.

Take note of the smell when the miso soup has just been made. It will be strong but still appetizing.

How to Tell if Miso Soup Is Bad

When miso soup has gone bad it will be:

1. Mold might be present

The first way to tell if your miso soup has gone off is to see mold developing. 

This will start at the edges before making its way across the surface and into the soup. 

The mold with be white in color but turn to blue-grey if left too long. 

2. Cloudy and/or slimy

This is a clear visual sign that your soup has gone bad.

Slimyness and cloudiness can indicate bacteria growth, which could make you sick. If you see this, discard it immediately.

3. Off smell

Miso soup always smells a little funky, but it should not smell bad or fishy.

If it smells different from the way it did when it was fresh, that’s a clear sign that it has gone bad.

How Long Does Miso Soup Last?

If properly stored, miso soup will last for up to 3 days.

Due to this short shelf life, we recommend making small batches of soup and storing the paste rather than the soup.

Since the paste has an almost indefinite shelf life, it will prevent any miso from going to waste if stored correctly.

Does miso soup go bad if left out?

We recommend that you always refrigerate your miso soup.

Any soup left at room temperature can lead to bacteria growth, which can make you sick.

For this reason, you should allow your miso soup to come to room temperature before transferring it to a container and placing it in the fridge.

What is the Best Way to Store Miso Soup?

The best way to store miso soup is in an airtight container in the fridge for up to three days.[*]

This will keep it fresh and stop the smell from taking over the whole fridge.

If you want to store the paste, we recommend decanting it into an airtight container and storing it in the fridge.

Here is a little step by step guide on how to store miso soup:

Step 1: Allow to come to room temperature

It’s very important to cool your soup before putting it in the fridge or it could cause bacteria growth. It can also raise the temperature of your fridge.

Step 2: Transfer to a fresh container

The best kind of container to use is a sealable glass jar or an airtight plastic container.

These containers will keep air away from the soup, which can make it go off faster. It will also keep the strong smell of the soup inside the container.

Step 3: Transfer to the fridge

Keeping the soup cold stops bacteria growth so it will keep your soup fresh for longer.

Miso soup will keep in the fridge for up to 3 days.

Can You Freeze Miso Soup?

Freezing miso soup is a great way to save excess soup that might otherwise go to waste.

To freeze miso soup:

  • Cool to room temperature before transferring the soup to an airtight container or Ziplock bag.
  • Label and date the bag and transfer it to the freezer

The miso soup can be frozen for up to 6 months.


BONUS: 5-Minute Miso Soup Recipe (Vegan, Gluten-Free)

Get Recipe: thrivecuisine.com


So now that we have got to know miso soup, what can we boil it down to?

  • Miso paste keeps indefinitely if properly stored
  • Miso soup will keep for up to 3 days in the fridge
  • Airtight containers are key to keeping the soup fresh and keeping the smell in

We hope you’ve enjoyed this metaphorical dive into miso soup and that you are leaving feeling hungry for this heavenly umami dish.

image of miso soup go off

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