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

                by Joost Nusselder | Updated:  December 16, 2020

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Our knowledge of flavor is limited often limited to principle four; sweet, salty, bitter, and spicy. However, a fifth flavor known as umami was introduced in 1908 as the lingering sensation on your tongue mimicking an explosion of flavor.

This definition might lead many people into believing that umami is either an unattainable flavor or requires years of culinary experience to prepare.

The truth is the flavor can be prepared using dashi – a cornerstone of Japanese cuisine that can best be described as a broth or a roux like alternative using two primary ingredients. The ingredients are kombu (kelp) and kezurikatsuo (fish scales).

Can dashi go bad and does it expire

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 sachet?

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 Kezurikatsuo

Based on several home chef experiences and some of our own, it suffices to say that freshly prepared dashi prepared with only kombu and kezurikatsuo 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:

Favorite Asian Recipes x
Favorite Asian Recipes

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.

Animal products 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 kezurikatsuo particles settling at the bottom of the bowl that had not been strained properly.

Prepared Dashi or Dashi Sachets

Prepared dashi is supplied in tea-bag sized pouches of 8 grams that can be readily prepared by adding in 1000ml 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 dashi sachets 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:


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:

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

Ever had trouble finding Japanese recipes that were easy to make?

We now have "cooking Japanese with ease", our full recipe book and video course with step-by-step tutorials on your favorite recipes.

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.