Add the tamari or soy, ginger, and kombu, and simmer for 15 minutes. Remove from heat and allow to cool. This stock must be cold before it is used. You will be using this stock to cook the seitan later. Warm water loosens the dough and makes the task easier.
Some people knead the dough while it is immersed in water in a bowl.
I prefer to rinse it under running water, with the flow stream about as thick as a pencil. The water will look very milky at first and then get more transparent . In the final rinses, use cold water to tighten the gluten. After about 10 to 15 minutes, you will begin to feel the dough become firmer and more elastic. The water will no longer become cloudy as you knead it.