Staple Recipe: Dashi Stock (slow cooker method)

Dashi stock is a staple in the Japanese kitchen and there are many ways to prepare it.

Traditionally, dashi is made by either soaking konbu in cold water for a long period of time, or heating konbu in hot simmering water for a several minutes (never boil though! Supposedly konbu creates a bitter taste if boiled). A popular variant of konbu dashi, and one I prefer to use in all my dishes, includes simmering katsuoboshi (dried bonito that has been shaved into flakes) along with the konbu for a richer taste.

Nowadays there are shortcut methods to making dashi stock. Probably the most common method is to use freeze-dried granules (commonly known as “Hondashi”), which you can buy from many stores, including online. It works similarly to how chicken bouillon works… dissolve the granules into water for instant flavored broth!

I’ll admit, I’ve used Hondashi in the past, before I became wary of food labels and hidden ingredients. Similar to chicken bouillon, Hondashi’s ingredients don’t necessarily reflect what you’d expect from the food it makes. Unfortunately, in addition to not having ANY mention of “konbu” in its ingredient list, Hondashi contains (surprise!) lactose. Lactose comes from milk, so as a person who cannot consume dairy, Hondashi is a surprising food ingredient that I cannot have.

jar of hondashi granules
HonDashi is a quick-solution for dashi stock, but unfortunately has milk product in it so is not good for people who can’t consume dairy.

In all honesty though, dashi stock is INCREDIBLY EASY to make and its 2 ingredients are both pantry-based shelf-stable items. While I understand the ease of keeping a box of ready-to-use Hondashi in the fridge or pantry, I highly suggest making dashi stock from scratch when cooking Japanese foods. Hopefully this method makes it easier for you!

Perhaps a bit unconventional, but the way I always make dashi stock is with my slow cooker! I have a 3-quart Instant Pot with a slow cooker function. I just toss my ingredients in there and let it cook on high overnight. By morning I have a pot full of dashi stock ready to use for any recipe I have for the week (or I freeze the leftover stock if I end up not using it).

One of the benefits to making dashi from a slow cooker is that you need less of the stock’s core ingredients per pot. Slow cooking extracts the flavor and nutrients from the seaweed and dried fish over an extended period of time, making sure that every drop of flavor is pulled out and dispersed into the broth. Additionally, because the slow cooker method never boils the content, you won’t end up with bitter broth. Instead you’ll get an ultra savory, rich, seafood-based broth that works perfectly to give your dishes that “umami” puch.

Special Ingredients:

dried konbu
Dried konbu usually comes in large sheets, but can be cut down to whatever size you need. I personally like cutting it into 1 inch squares and storing it in a jar in my pantry.
Katsuoboshi is dried bonito that has been shaved and packaged as flakes. It comes in various sizes of packaging and flake size, depending on how you want to use it. All of them work for dashi stock, but commonly the larger-flake bags are used.

By the way… dashi stock is useful in dishes beyond Japanese and Asian cuisine. One of my favorite ways is to use it as a liquid base for cioppino or other seafood-based soups and stews.

dashi stock in 2 quart containers

Slow Cooker Dashi Stock

A easy-to-make overnight Japanese dashi that results in a rich and umami broth ready for use in whatever recipe you have planned
Prep Time 1 minute
Cook Time 10 hours
Course Base Recipe
Cuisine Japanese
Servings 1 quarts


  • 1 slow cooker I have a 3-qt instant pot with slow cooker setting


  • 4-6 1-in squares dried konbu
  • 1/4 cup loosely packed katsuoboshi
  • 10 cups water


  • Add everything to your slow cooker and turn it on to high. Let it cook overnight, at least 8 hours (some liquid may evaporate).
    4-6 1-in squares dried konbu, 1/4 cup loosely packed katsuoboshi, 10 cups water
  • Strain the broth and store in the fridge for up to 1 week. Or freeze for longer storage.


Leftover konbu and katsuoboshi makes for a great dog treat if your dog is in to seafood flavors. Seaweed is very healthy for dog kidneys. Ours loves it. 馃檪聽
Keyword broth, soup, stock

Recipes that use dashi stock

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