
Dashi is a broth made by extracting flavors from ingredients by boiling them. Yet unlike typical soup stocks made from a variety of mixed ingredients, dashi relies on only one or two simple ingredients. The beauty of this simplicity, however, is in its ability to enhance and harmonize the flavors of the other ingredients it’s paired with, creating a dish that is more than the sum of its parts.
Shiitake mushrooms, konbu (kelp) and katsuobushi (dried tuna flakes) are three main ingredients used to make dashi in Japanese cuisine. Here's how to store each to maintain the best flavor and freshness.

How To Store Shiitake Mushrooms
Shiitake dashi is made from dried shiitake mushrooms that are rehydrated to create the dashi.
At room temperature
Dried shiitake are best stored in a cool dark place away from high temperatures and humidity. Ideal storage temperature is about 40°F/5°C and about 40% humidity. It is safe to store dried shiitake in a plastic bag as long as there is a desiccant in it or in an airtight container.
How To Store Konbu
There are 2 major principles in storing konbu.
Store in a place with little to no humidity
Moisture is the number one enemy of konbu. When exposed to moisture mold can occur. You can store konbu in a Ziploc bag or sealable container to prevent exposure to moisture.
Store away from direct sunlight
When exposed to direct sunlight the umami and general flavor components of konbu can deteriorate, as well as the color.
How to Store Katsuobushi
There are 2 major principals in storing katsuobushi. It is important to eat it prior to it's best by date because the quality of the flavor can deteriorate.
Store in a place with low humidity and away from direct sunlight
Katsuobushi is very sensitive to moisture. If it gets damp, the flavor will deteriorate and it may become moldy. To prevent exposure to moisture you can put it in a Ziploc bag or container.
Store it in a Refrigerator
After opening the package it is recommended that you seal it and put it in the refrigerator. It is suggested not to put the katsuobushi in the vegetable section of the refrigerator due to higher humidity levels there.
About the author:

Anna Ayvazyan
Hi I'm Anna, currently a 5th year JET (from Australia) working in Himeji. I love exploring Japan and finding new things to experience and try, particularly sweets!
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May 19, 2022
Thank you for your comment Caitlin! We realized we weren’t clear that we’re referring to dried shiitake and not hydrated ones so we’ve updated the blog for this clarification. Thank you for your feedback!