You find a tub of miso sitting in the back of your refrigerator that you completely forgot about. Is it still good to eat or is it maybe time to toss it? Let’s discuss how long miso lasts in the refrigerator before it goes bad.
What is miso?
Miso is a cultured, fermented paste made from soybeans and is commonly used in Japanese cooking in dishes like miso soup. It has a brownish-red color and a paste-like texture and is commonly sold in a plastic tub. Miso paste has a few varieties based on what is used to make it and each variety can be used in different applications.
Miso is made from a combination of steamed soybeans, a grain like white rice, and koji, a steamed grain mixed with a mold called Aspergillus oryzae. The koji is fermented and used as the starter culture for miso and other foods like soy sauce, similar to sourdough starter.
What does miso taste like?
Miso has a very salty taste and an umami flavor that is savory and delicious. It is made from soybeans, so it has a bean-y flavor. The fermentation process strengthens its flavor and leaves distinctive flavor notes in your mouth. By itself, miso is very strong and salty, so it works best in dishes where it is diluted in water such as in a soup or sauce.
Varieties of miso
Miso comes in a few varieties that are used in different applications. The type of miso is largely determined in what ingredients are used to make it. For example, if white rice is added, white miso is made and if red rice is added, red miso is made. Another example is barley miso, which is made when barley is added to the mix.
How long does miso last in the fridge?
Miso has a very long shelf life because it is a fermented food. But, it does lose quality after a period of time, so it’s best to consume it within one year after opening. Unopened miso can last longer, so be sure to check the expiration date. Once opened, it begins to decrease in quality since it is exposed to the open air.
Can miso stay out at room temperature?
Miso shouldn’t stay out at room temperature for longer than two hours. If you are using miso paste in cooking, be sure to put it back into the refrigerator after adding it to your dish. The refrigerator is the best place to store miso to maintain best quality and avoid foodborne illness.
Temperatures between 40°F and 140°F are considered the danger zone. This means bacterial growth is at its height between these temperatures. Since room temperature is typically between 70°F – 80°F, it’s best to keep miso in the refrigerator where storage conditions are the best.
Can you store miso in the container it came in?
The best way to store miso is in the container it came in. If this isn’t a possibility or you made your own miso from scratch, it’s best to store it in an airtight container, whether that’s a plastic or silicone bag or a storage container. The more the miso is exposed to open air, the faster it will go bad, so make sure it is exposed to the least amount of air as possible.
How to tell if miso has gone bad
Even though miso has the potential to last a very long time, if exposed to too much air or stored at incorrect temperatures, it can go bad. You can check for signs of spoilage by monitoring the miso paste’s appearance, smell and taste. Here are some signs to look out for:
- The miso is darker than normal. Miso grows darker as it ages. This doesn’t necessarily mean it’s unsafe to consume, but the flavor profile will be different. If you enjoy the new flavor, that’s fine, but if not it’s time to toss.
- The miso has a sour taste. Again, it doesn’t mean the miso is unsafe to consume, but it’s a sign the fermentation process has gone on for quite a long time and it may be time to get a new batch.
- The miso has grown a layer of white, fuzzy mold. If there is mold growth on the surface of the miso, you can always scrap it off and use the good stuff underneath. But if the idea of mold freaks you out, you can always toss it and get a new one.
- The miso smells off. Give your miso a good sniff. If it smells a bit off, it may be a good idea to toss it. That being said, the smell of alcohol is normal and is produced during fermentation.
For the most part, miso doesn’t really go bad. It just continues to ferment and during this process it may grow darker in color and develop a more sour taste. If you are uncomfortable with this or prefer the taste of fresh miso, you may feel better just tossing it. And that is totally fine!
How long until miso soup goes bad?
Miso soup can last up to 2-3 days in the refrigerator before going bad. The shelf life of miso soup is much shorter than that of miso paste largely due to the high water content. The presence of water tends to increase spoilage. Make sure to transfer your leftover miso soup to an airtight container and refrigerate it as soon as possible to increase storage time.
Other ways to store miso
If you don’t want to store miso in the container it came in or you made your own homemade miso, you can always store it in another way. Some examples of this include an airtight container, in plastic wrap or in ice cube trays for easy portions. Just make sure to cover your miso so it isn’t exposed to air in the refrigerator.
What recipes use miso?
There are so many delicious recipes that incorporate miso in Japanese cuisine. More notably is miso soup, which is commonly served in Japanese restaurants, typically with silken tofu, wakame seaweed and green onions.
Miso is also used in marinades for meat dishes, in salad dressings, soups and vegetable dishes. Examples of dishes include miso salmon, miso salad dressing, miso ramen, miso butter, miso eggplant and miso butter cookies. You can find more recipes here.
Is miso healthy for you?
As a dietitian, I try to avoid the terms healthy or unhealthy because all foods contain a mixture of beneficial and non beneficial components. Along with this, some components are good in small doses but unhealthy in large amounts, such as salt.
While miso paste has a rather high salt content, there are lower sodium options available and this doesn’t take away from its other benefits. Miso is fermented, meaning it contains beneficial bacteria called probiotics which can provide some health benefits.
Where to find miso
You can find miso at many grocery stores, but especially Asian grocery stores. It will be in the refrigerated section since it requires refrigeration to avoid spoiling. If you are looking at the miso section at an Asian grocery store, there may be many options. I recommend starting with awase miso, which is a mix of white and red miso. The Miko Brand (affiliate link) is very good.
How to make homemade miso soup
Homemade miso soup is rather easy to make. Start with warming up some water in a pot over medium heat. You can add dashi for extra flavor but this isn’t necessary. Add your tofu and dried wakame flakes. Once the wakame is rehydrated, turn the stove to low heat or turn it off all together.
Transfer some of the water to a small bowl and stir with miso paste (about 1 tablespoon for every 1 cup of water), then add back to the pot. Stir until the miso is fully dissolved and top with green onions. This can be served as an appetizer or side dish.
