Begin by taking a quarter of the chopped Napa cabbage and placing it in a large bowl.
Sprinkle a quarter of the kimchi salt over the cabbage.
Pour in a quarter of the cold filtered water and let the mixture sit for at least 90 minutes, stirring gently every 30 to 45 minutes.
After soaking, rinse the cabbage thoroughly to remove all the salt.
To prepare the sauce, mix four tablespoons of sweet white rice flour with one and a half cups of water.
Add gochugaru, minced garlic, grated ginger, and fish sauce to the mixture, then taste and adjust as needed.
Combine the rinsed cabbage with the sauce and mix everything together well.
Allow the mixture to sit at room temperature for 24 hours before transferring it to the refrigerator.
