Heat the mirin: Add the mirin to a microwave-safe container and heat for 30 seconds to 1 minute to evaporate the alcohol. Then set aside and let it cool.
Prepare the citrus juice: Squeeze the Meyer lemons to extract the juice. The amount of juice may vary depending on the size of the citrus. From 2 medium Meyer lemons, you will get about ⅓ cup of juice. Adjust the amount of soy sauce to be 1.5 times the amount of citrus juice
Mix the base: In a bowl, combine the Meyer lemon juice, soy sauce, and cooled mirin.
Infuse the ponzu: Pour the mixture into a clean jar or airtight container. Add the kombu and bonito flakes, then mix gently. Cover and let it infuse in the refrigerator for 3–5 days. This allows the flavor to mellow, the acidity to soften, and the umami to develop.
Strain and store: Strain the ponzu through a fine mesh sieve or strainer, then transfer it to a clean container or bottle for storage.
