2 quarts water
4” dried kombu (seaweed)
4 ounces bonito flakes (dried fish)
1 tsp vinegar

In a large stockpot, add water, vinegar, and kombu and heat on medium. As the water starts to come to a fast simmer, but before boiling begins, remove the kombu and add the bonito flakes. Simmer on low for 2 hours, but not longer than 4 hours. The flakes will fall to the bottom of the pot when the dashi is ready to be strained. Use a fine mesh strainer to remove flakes from dashi.