Place all ingredients in a pressure cooker or stock pot. I have a 6 quart Instant Pot and place all ingredients in the pot, then fill with water to the max fill line.
I set my Instant Pot to manual for 10 minutes. If cooking on the stove, cover and simmer at least an hour.
Remove kombu and bay leaves and discard.
Use an immersion blender (or put in a blender in batches, but be careful blending hot liquids).
Pour into storage containers (I use mason jars) and let cool before refrigerating.