Remove debris and any hard, red stems from the picked yomogi. Place in a bowl of water and wash by gently rubbing 3-4 times.

Once the water is clean, drain the yomogi in a colander. Add salt to a deep pot and fill halfway with water. Bring to a boil and add the yomogi.

Stir and bring back to a boil, then add baking soda (it will bubble, so lower the heat slightly). Boil for 1 minute, then cool in water and drain in a colander.

Place the colander in a bowl of water for about 1 hour to set the color. Squeeze out excess water and process into a paste using a food processor. Wrap about 20g portions in plastic wrap and freeze.

I used some that I froze last spring this year, and it was fine (^_^; It lasts for a year♪