Does miso ever expire?

In this article, we answer the following question: Does miso ever expire? We discuss how to choose, store, and cook miso. We also explain how you know if Miso has gone bad. 

Does miso ever expire?

Like all food products, miso does expire, and it can go bad if kept under the wrong conditions. Miso has a high concentration of salt and is a fermented paste, thus its shelf life is very long and can even be safely consumed after its expiration date. However, people who live in very hot places are better off keeping it in the fridge. 

Miso is a type of pasta fermented with salt and water that is obtained from soybeans and sometimes also from other cereals. Among its properties, we find its high antioxidant power and its digestibility. Miso soups are well known in the kitchen, but it can also be used in other dishes.

Made with soy, this Japanese paste is delicious when added to beef stews or when used as a sauce for chicken legs and whitefish. Miso paste is used to prepare soups, sauces, marinades, and purees. Miso is one of the richest sources of protein and vitamin B12 and is often used as a meat substitute in most oriental vegetarian dishes.

How to store Miso

Miso is produced following a fermentation process, which itself acts as a natural preservative if done correctly. Miso, a natural product, is stored in large barrels, in which it maintains its nutritional qualities.

Trademarks produced industrially are pasteurized before being packaged, in order to stop the fermentation process, which produces carbon dioxide, which sometimes causes the packaging to break. In the maturation process of commercial miso variants, synthetic dyes, alcohol, and other additives are added that speed up the maturation process.

Miso is sold as a paste, packaged in sealed containers. Store in the refrigerator after opening. Miso natural is a living food that contains many microorganisms such as tetragenococcus halophilus, which can be destroyed in long cooking. Therefore, it is recommended that miso be added to soups and sauces just before the dish is removed from the flame.

It seems that miso is best used without cooking to keep koji kin crops alive. It is a popular practice in Japan to add miso to food only after it has cooled.

So keep the miso in the fridge. It’s best to do this even if you haven’t been able to open the package. Use light misos within 9 months of purchase and dark ones within 18 months.

How do you know if Miso has gone bad?

When Miso is no longer safe to consume it can become rancid, have a bad taste and smell, or change in color or appearance. If you observe such changes, it is better not to consume the product. Mold on the tip signals the end of the paste’s life, do not consume it!

Choose, cook and store the miso correctly

You will find the miso in herbalists, natural product stores, oriental product stores, and organic supermarkets in two formats

1. In sachets, dehydrated and prepared to make a soup;

2. In the form of a dark past in a glass jar or airtight plastic bag. If you buy the pasta directly from the fridge.

In general, you can find three different types of Miso:

Hatcho miso: from soy.

Kome or genmai or shiro miso: soy and rice.

Mugi miso: soy and barley.

Which is better?

As for the taste, it depends: that of soups in Japanese is usually genmai, which is milder; The hatcho is strong in flavor and the mugi is between the two. Normally the criteria used to know which one you should consume has to do with the weather.

Paul Pitchford, author of the book Healing with whole foods, makes the following recommendation:

  • The dark and long-fermented misos, for cold climates or days;
  • The clear and short-fermented misos, for warmer climates;
  • The misos of a reddish color and moderately fermented, for temperate climates.

The best thing is to try them all and stay with the one you like the most. And always buy unpasteurized miso: the pasteurized one has lost much of its properties. Pitchford also explains that miso has the property of absorbing toxins from plastic containers, so it is best stored in glass containers.

How should we cook miso?

When you cook with miso you have to dissolve it before with a little water and you have to add it at the end of cooking and heat it slightly but never boil it, because it will lose a good part of its live enzymes and therefore its medicinal properties.

As we explained above, another common mistake is to abuse its consumption: miso has a very strong flavor and is a very contractive and concentrated food, so with a teaspoon per bowl (making a soup) there is already more than enough. Take it every two or three days and always dissolved in soups, sauces, or stews and as a first course, to prepare the stomach for good digestion.

If it is taken in soup, it enhances digestion and is distributed better and faster throughout the body. Nor should it be eaten cold, spread over a piece of bread, even if it is delicious.


In this article, we answered the following question: Does miso ever expire? We discussed how to choose, store, and cook miso. We also explained how you know if Miso has gone bad. 

Our recommendation is to keep the miso in the fridge in order to prolong its shelf life. It’s best to do this even if you haven’t been able to open the package. Use light misos within 9 months of purchase and dark ones within 18 months.

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Hi, I am Charlotte, I love cooking and in my previous life, I was a chef. I bring some of my experience to the recipes on this hub and answer your food questions.