How Long Does Miso Paste Last In The Fridge?
If you're a fan of miso soup or miso fried rice, you probably have a bag or a tub of this umami-packed paste sitting in your fridge. But how long can you keep it there? As a fermented product, miso is definitely long-lasting — unopened, it will keep for several years.
Once a package of miso has been opened, however, it won't stay fresh indefinitely. The first thing to check is always the use-by date. Big miso producers like Marukome don't give a concrete amount of time, but they do suggest eating it before it hits the use-by date. These dates depend on the type of miso and are based on peak quality rather than spoilage. In general, the darker the paste, the longer it will last. If stored properly in the fridge or freezer, miso will maintain its flavor for anywhere from a few months to upwards of a year or more.
When you keep your miso for a long time, chemical reactions between the sugars, proteins, and amino acids will begin to darken the color and change the taste. These changes aren't dangerous, however. Mold is something to look out for, though, and you should toss the container if you see some. You should also note any changes in the taste. If your miso soup, for example, stops tasting the way it should even when you use the right paste-to-water ratio, that's a sign that the product isn't in the best shape anymore. Miso makes food better, but not when it has a flat and dull flavor — even if it is still technically safe to eat.
How to store miso paste to keep it fresh
After you've opened a tub of miso, it needs to be kept at a consistently low temperature. That's why storing it in the main compartment of your fridge (not in the door) is recommended for maintaining peak quality for as long as possible. Keeping air away from the miso is also important, so add a layer of plastic wrap or parchment paper pressed to the surface of the paste to keep it in good condition.
If you want to keep your miso for longer than the few months suggested by the use-by date, you can freeze it. Any impact on the flavor is minimal, and many people happily freeze their miso (including me!). The color stays more stable, and the paste doesn't actually freeze solid, so you can still scoop out a few spoonfuls without any extra effort. If you choose the freezer, make sure to still cover the surface with parchment paper or plastic wrap. The last tip is to keep moisture away from your miso, which means any spoon you use to scoop it out should be clean and completely dry.