The majority of recipes in English for making dashi simply call for shaved katsuobushi to be steeped in hot water before straining. What they usually fail to specify, is that these recipes are designed specifically for thinly shaved katsuobushi (usukezuri/薄削り) as their large surface area to volume ratio allow for quick flavor extraction. 

In actuality, katsuobushi can also be brought as thicker shavings (atsukezuri/厚削り) of anywhere around 0.8mm to above 1mm, and are not suitable to be made into dashi this way. Whether or not they’re unaware, or have deemed it irrelevant to their target audience (as thick shaved katsuobushi can be hard to buy outside of Japan), in our opinion, thick shavings dashi stock is one of the most under-appreciated Japanese food preparations in the English speaking world. The stock is not only highly flavourful, but is also able to stand up to pairing with rich flavors like meaty stews and aged miso. Because of this, we reckon that it’s used just as commonly in restaurants around Japan as thin shavings, just not by those that receive accolades and hype from food critics. 

What might come as a surprise to most people about making dashi stock from thick shavings is that you need to boil them at a simmer for 10 to 20 minutes in order to fully extract all the flavor. It sometimes feels as though the very idea of boiling katsuobushi flakes has become a taboo that is deeply ingrained with people due to misconceptions that have been spread surrounding dashi. However, this is only true for thin shavings, specifically when using the highest quality honkarebushi in an attempt to make the purest expression of dashi. Your neighborhood lunch restaurant most likely boils katsuobushi for maximum flavor extraction. 

We also recommend thick shaved katsuobushi when making our tamago kake gohan sauce.

To shave your own thick shavings from a katsuobushi block, you simply have to adjust the blade so that it sticks out from the plane more and then you shave it in the same way. 

Thick shaved katsuobushi dashi recipe

The ingredient quantities are the same for ichiban dashi. Fresh thick shaved katsuobushi should have a red hue to it. If it is completely brown, chances are it is no longer fresh. It is recommended that the dashi is simmered without a lid to allow any fishy aromas to escape. The dashi should also not be stirred as it can break up the shavings into smaller pieces, making the dashi cloudy.

30g of thick shaved katsuobushi (atsukezuri/厚削り)

1000 ml of water (ideally soft water)

Bring the 1000 ml of water up to a boil.

Add in the katsuobushi and immediately reduce the heat to barely a simmer with only the occasional bubbles rising. 

Simmer for 10 minutes for a light extraction, or 15 to 20 minutes for a strong extraction.

Whilst simmering, constantly skim off any scum or foam that rises to the surface. 

Line a strainer or colander with muslin cloth and pass the dashi through it, allowing the dashi to drain naturally for 1 to 2 minutes. Do not squeeze out any excess liquid from the flakes. 

You’d typically obtain 700ml to 800 ml of stock. If not used immediately, refrigerate for 5 days or freeze for up to 3 months without loss of flavor.