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How to store miso

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Soup, salad dressing, and marinating meat, miso is delicious and healthy condiment that can be served in various dishes from breakfast to dinner. Once a miso package is opened, the shelf-life depends on proper storage to prevent it from going bad.

Miso generally has a low danger of expiring since the fermentation process continues, especially when the package remains unopened. The safety level of consuming expired miso is still safe, but quality may decline. 

Taste and smell may be unfamiliar, but the worse is if the miso paste has decolorized. The storage method is key to how long miso paste can last, especially when the miso container is opened.

How do you store miso? It depends if the package is open or not! An unopened package of miso can last up to a year without going bad since the fermentation continues and it doesn’t require a preservative. 

If the miso jar hasn’t been opened yet, placing the container in a cold, dark and dry area at room temperature is okay. 

Storing the jar in the kitchen cabinet is okay, but do not place the container near the oven or stove because the heat from those appliances will affect the quality of miso with time. 

On the other hand, quality degradation accelerates once the container is opened. Store opened miso container in a refrigerator to slow down the fermentation process. 

Nonetheless, it’s necessary to seal the container properly before placing it into the fridge since a small amount of air can ruin the miso. Anytime a serving is required, scoop the miso paste with a clean and dry spoon to prevent cross contamination.

Bottom line, fermentation takes place as long as the miso is sealed and no air enters the container, which is why an unopened miso can last so long.

This article answers frequently asked questions about storing opened and unopened miso. Included below are the best storage tips to apply for maintaining the flavor of your favorite miso.

Does miso go bad once opened?

Yes, miso does go bad once opened. The paste usually retains optimal quality for about 3 months after opening, however the degradation of taste and smell slowly decreases.

When stored properly, the open package is unlikely to expire in a short time. Ensure the lid seals the container properly to prevent air from entering the container. 

An open package of miso paste should not be left exposed to the atmosphere and warm temperature. Microbial contamination will eventually make the miso paste go bad. 

The shelf life of an open package of miso ultimately depends on the storage method.

Does miso paste need to be refrigerated after opening?

Yes, miso paste does need to be refrigerated after opening. In fact, the fridge is the best place to store miso paste since the low temperature slows fermentation. 

Once the miso container is open, the quality in terms of smell and taste degrades, especially when not stored properly. Moving miso to the refrigerator slows down the degradation process to prolong its shelf life up to three months. 

However, this can only help if the container is sealed properly. No air can enter the container so the miso avoids bacterial contamination. 

Additionally, a clean and dry spoon must be used to scoop to prevent contaminating the remaining miso paste.

Some miso pastes brands do not encourage refrigeration once the package has been opened. So, if the label on the miso packaged urges not to refrigerate, in such a case, store in the pantry at room temperature in a cool, dark and dry area.

How do you store a bag of miso?

Most miso paste comes in a container with lid which makes it easy to store without transferring it. However, some brands comes in a plastic bag that makes it harder to store once the package is opened.

To store a bag of miso, tightly wrap with plastic wrap or safely transfer into airtight container or ziplock bag to prevent air contact from drying and oxidation. 

If the bag hasn’t been opened, it can be kept at room temperature in a cool, dark and dry storage area like in a kitchen cabinet. 

Be aware to keep it away from heat sources like stoves and ovens or sources of lights like a brightly lit window. The pantry is the best place to store bags of miso, but when it’s not available, the kitchen cabinet can serve the purpose.

The best way to store a bag of miso is by placing it in the refrigerator to prolong its shelf-life, especially for the open bag. It makes it easier to reheat miso quickly without the need for defrosting.

It is also possible to use a freezer, but the temperature should be kept higher than -5℃ or 25℉ since the aroma and the flavor can be affected below this temp. Always seal the bag properly to prevent air from entering the bag or causing freezer burn that dries out the paste.

How do you store miso paste once opened?

Once the miso jar has been opened, it’s recommended to store the container in a fridge to prolong its shelf-life. 

Suppose the manufacturer’s label doesn’t recommend the use of refrigeration once the container is opened. In that case, it’s good to leave the open package at room temperature in a pantry area that is cool, dark and dry. 

Keep the package away from heat and direct sun light. Also, use the freezing method to extend the shelf-life, but avoid keeping the temperature below -5℃ or 25℉ to prevent the miso paste from deep freezing.

To maintain the moisture level of miso, consider pressing a piece of parchment paper or plastic wrap onto the surface of the paste before placing the lid. If miso is not properly covered, it gets darker and denser over time. 

Tips for storing miso

No matter red, yellow, or white miso, storing properly retains its quality and extends the shelf life. However, the method may vary depending on the miso being opened or unopened. 

Here are useful tips to store miso properly:

  • The most suitable method to store miso is a refrigerator, especially for opened miso containers. Tightly seal the miso container before placing it into the refrigerator to prevent air from entering, which can cause bacterial contamination.
  • Store the miso paste in a freezer, but keep the temperature above -5℃ or 25℉ because frozen miso lacks aroma.
  • Unopened miso can be placed in a pantry at room temperature in a cool, dark and dry area.
  • Should be stored in places away from the sunlight or heat sources like stoves, oven or bright window.
  • Place a parchment paper or plastic wrap as a skin directly on top of the miso before placing the lid to keep moisture intact.
  • If the miso package label say “Do not refrigerate open package once the container is open,” then store it at room temperature instead. 
How to store miso

Storing Miso: Conclusion 

Due to the fermentation process, an unopened package of miso may last for a year or longer without quality degrading as long as the package remains sealed. 

When a refrigerator is not available for keeping leftover miso, a room temperature pantry in a cool, dark and dry area is the best storage method. Or freezing above temperature above -5℃ or 25℉ is recommended as a very low temperature takes away the miso flavor. 

The more often the miso container is open, the faster its quality degrades due to bacterial contamination.

Once the miso container has been opened, it’s advisable to scoop the needed portion with a clean and dry spoon to prevent cross contamination. Signs suggesting the miso paste has gone bad are a sour taste, funky smell, and color change.

The quality of opened miso becomes affected in terms of taste and smell, but it’s still safe to consume unless the miso paste has decolorized. At that point, it’s advisable to throw the leftovers away. 

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