How to Get Rid of the Astringency of Warabi (Bracken Fern) with Baking Soda

How to Get Rid of the Astringency of Warabi (Bracken Fern) with Baking Soda

Fresh bracken fern is a springtime mountain vegetable. You need to remove the astringency (bitterness) from the bracken fern before cooking with it. This is a simple method where you just pour boiling water over it, rather than boiling it.


Warabi (bracken fern)
as needed
Baking soda
as needed
Boiling water
as needed


1. Wash the bracken fern thoroughly and trim off 1-2 cm of the stems (I often find the cut surface of store-bought fresh bracken fern stems to be blackened by the astringency).
2. Sprinkle baking soda on a plate, hold the tips of the bracken fern, and dunk the stems into the baking soda (the stems will be sticky, so the baking soda should easily stick).
3. Put the bracken fern into a bowl large enough to contain them, sprinkle on a pinch of baking soda, and pour boiling water over them until they are immersed (bubbles should form from the stems).
4. Cover with a plate so that the bracken fern will not float to the top and let sit overnight to remove the astringency.
5. This is what they should look like the following day (after about 8 hours). The astringency should be removed from the bracken fern and the color of the water should be dark green.
6. Rinse the bracken fern and soak it in fresh clean water. If the water still becomes cloudy, drain and refresh the water until it becomes clear.
7. Since the bracken fern is not boiled, if you are making ohitashi (blanched vegetables with soy sauce or something similar), blanch it before using. The bracken fern will keep for 4 to 5 days, as long as you refresh the water everyday and store it in the refrigerator.

Story Behind this Recipe

I have tried getting rid of the astringency by boiling the bracken fern, but it was a failure, and it became too soft, and the bitterness from the baking soda was too strong. I have been using this method ever since.