Can You Boil Dashi? Here are Things You Should Know About It!

by Joost Nusselder | Updated:  June 16, 2020
I love creating free content full of tips for my readers, you. I don't accept paid sponsorships, my opinion is my own, but if you find my recommendations helpful and you end up buying something you like through one of my links, I could earn a commission at no extra cost to you. Learn more

Dashi is a kind of soup stock essential in Japanese cuisine. The ingredients may vary, but the cooking methods are just the same.

You can certainly boil dashi and make it from scratch, or boil dashi powder in water to use it in your recipe. Or you can soak the ingredients in cold water to make a dashi stock.

dashi in a bowl

What is Dashi?

Dashi is a kind of stock made of one or a few ingredients. In Japanese cuisine, dashi is
essential that most people always have a supply of in their kitchen.

People use dashi as the main ingredients to many kinds of Japanese dishes, such as Miso Soup, ramen, shabu-shabu, and agedashi tofu.

Also read: authentic dashi recipe and dashi substitutes

Types of Dashi Ingredients

Even though it is simple, the dashi has many variations based on the ingredients. Some are animal-based, while some can be completely vegan.

Here are the types of dashi you can find in Japanese cuisine:

  1. Kombu Dashi, made of Kombu (dried kelp sheet)
  2. Katsuo Dashi, made of katsuobushi (bonito fish flakes)
  3. Iriko Dashi, made of dried anchovies or sardines
  4. Shiitake Dashi, made of shiitake mushroom
  5. Awase Dashi, made of mixed ingredients, mainly the kombu and katsuobushi

Awase Dashi is the most common type of dashi in Japan in a non-vegan category. But for the vegan, Kombu Dashi is the most popular one.

These two are what most people usually make in their house. Meanwhile, the other types of dashi are just common in restaurants and a few households.

The First and the Reused Dashi

Most people use new ingredients to make dashi to get the best quality of stock, in terms of taste and fragrance.

This kind of dashi is called Ichiban Dashi, which means the first dashi.

However, the left-over ingredients of the dashi are not so bad that many people think it would be a shame to throw them away too soon.

Hence, these ingredients are then reused to make another batch of dashi. It is called the Niban Dashi. The flavor and consistency are lighter than Ichiban Dashi, but it is still tasty.

How to Make Dashi

dashi in a bowl of ramen

You can make dashi either by boiling it on the stove or by coldly brewing it. Both techniques can be effective to bring out the fragrance and long-lasting savory flavors.

Here is the example of how to make Awase Dashi with those two different techniques:

Boil the Dashi

Put the water and the kombu in a pan over the stove. Start the fire with low heat and slowly turn it up to medium heat. When the water is almost boiling, gently take the kombu out of the pan. It should be around 10 minutes after you start cooking.

Add in the katsuobushi and let the water boil again. After that, reduce the heat and simmer for about 30 seconds. Turn the heat off and let the katsuobushi to sink in for about 10 minutes. Strain it with a sieve and your dashi is ready.

Also read: this is wafu dashi or “Japanese dashi”

Cold Brew

Cold-brew dashi takes more time to make, but the process is very simple. You only need to put the water and all of the ingredients in a bottle or jar and close it tightly. Leave it for a few hours to let the juice seep into the water.

Cold brew dashi in a jar

In summer, this process takes about 2-3 hours to make. Meanwhile, you need to wait up to 4-5 hours during the wintertime. You can also cold brew dashi overnight by storing the bottle in the fridge.

After the process ended, strain dashi with a sieve. Now your dashi is ready.

Either you boil the dashi or using the cold brew technique, it is important to take out the kombu at the right time. Because your dashi will be slimy and bitter if the kombu is overly brewed.

That’s why you need to put the jar in the fridge if you’re going to let it brew overnight. The cold from the fridge will slow the process.

If you are not going to use the dashi right away, you can place it in a well-closed jar or bottle. Then, store it in the refrigerator. The dashi could last 3-5 days at a cold temperature. You can also keep them in the freezer for up to 2 weeks.

Also read: use these dashi powders if you don’t want to make it yourself

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.