Can Dashi Go Bad: How Long Does it Last Until it Expires

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Umami can be prepared using dashi – a cornerstone of Japanese cuisine that can best be described as a broth like alternative using two primary ingredients. The ingredients are kombu (kelp) and katusobushi (dried bonito fish).

But you’re probably already familiar with what dashi is and just how simple it is to make it.

The question is, how long does it last? How long will it last in the fridge? How long will it last in the freezer? And, how long will it last in its packet?

Can dashi go bad and does it expire

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Storing Freshly Prepared Dashi

Restaurants and fine dining experiences insist on preparing fresh dashi for each meal. At home, on the other hand, you might just be looking to prepare it enough to last for one meal. Alternatively, you could be looking to prepare it enough to last for several meals.

In either case, preparing dashi is incredibly simple. For the most part, the broth is purely vegan with only two ingredients. Although there are several variations to the broth which can incorporate varied ingredients.

Storing Dashi With Only Kombu and katsuobushi

Based on several home chef experiences and some of our own, it suffices to say that freshly prepared dashi prepared with only kombu and katsuobushi can last for up to a week when refrigerated or a maximum of three months when frozen.

However, these figures are really stretching the timeline out too thin. It’s best to use the broth within five days when refrigerated and a month if frozen. Granted the broth won’t necessarily go bad if left for the maximum period of time, but it will lose some of its flavors.

Storing Dashi With Other Ingredients

Other ingredients commonly used in preparing dashi include:

  • Shiitake mushrooms (dried)
  • Shrimp
  • Adzuki beans
  • Scallops
  • Toasted soybeans
  • Sardines (also the dried kind)

Adding any of these ingredients can reduce the storage time of dashi even further. In all fairness, the longest you can preserve dashi with its flavor still intact would be with cold-brewed kombu and not adding in the kezurikatsuo.

Fresh animal products and vegetables do not last as long and it would take 4 days maximum in the fridge for dashi to go bad or less than a month if frozen.

Also read: these are some great dashi granules of fresh dashi substitutes you could use

How Can You Tell if Stored Dashi Has Gone Bad?

Here are some ways you can tell if stored dashi has gone bad:

  1. The smell is sweet, instead of smokey.
  2. A film has formed around the edges and on the surface.
  3. It has a stickier consistency.

Dashi hasn’t gone bad, even if it seems like it, if there are sediments at the bottom of the broth.

These sediments are just the katsuobushi particles settling at the bottom of the bowl that had not been strained properly.

Prepared Dashi or Dashi packets

Prepared dashi is supplied in tea-bag sized pouches of 8 grams that can be readily prepared by adding in 2 cups of water. Prepared dashi is an easier alternative for most people who just want dashi for one bowl of miso soup.

While the manufacturer would have specified the expiration dates on the back of the product, it usually lasts from anywhere between eight months to a year before going bad.

Alternatively, you can check to see if the dashi has gone bad by:

  • Smelling it; if the smell is either sweeter than usual or just smells like it has gone bad, it probably has
  • If the particles are clumped together. It is important to note that ‘powdered’ dashi isn’t actually powdered. It has more of a pellet-like structure. If the pellets are clumped together, the glutamate has gone bad and you won’t get the umami flavor that’s relying on it.
  • The color goes from its usual brownish tone into more of a green or blue one.

Can you freeze dashi stock?

Dashi should last in the fridge for up to a week but you can freeze it to keep it for 3 months. Just pour the broth into small zip lock bags so you can pick up and thaw how much you need without having to thaw out all of it at once.


Dashi is the cornerstone of Japanese cuisine. It’s found everywhere in Japan from fine-dining restaurants to home chefs and novices. All of whom are looking to relish the flavor of umami – something Japanese cuisine is famous for.

For dashi to go bad, you’ll have to rely primarily on your sense of smell, sight, and taste. Although there are specific considerations, such as:

  • The lid has to be tight to not let air into the storage container
  • Properly straining the Benito particles
  • Storing dashi sachets away from moisture and water

Refrigerated dashi can last from 4-7 days (depending on the contents) and frozen dashi can last from 1-3 months. Dashi sachets last from 8-12 months unless specified otherwise on the box.

Also read: These are the best instant dashi packets to use without the hassle of fresh

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Joost Nusselder, the founder of Bite My Bun is a content marketer, dad and loves trying out new food with Japanese food at the heart of his passion, and together with his team he's been creating in-depth blog articles since 2016 to help loyal readers with recipes and cooking tips.