Put all ingredients in the food processor except for the vital wheat gluten. Mix for about 30 seconds.
Add the vital wheat gluten and continue to mix at a medium speed for 5 minutes. Your food processor will likely move around on the counter a lot so you may need to stand there and hold it. The mixing step is important if you want that shredded, tender texture in your seitan, so don't skip it!
Remove the dough from the food processor and put it on the center of a large piece of parchment paper.
Wrap the parchment paper around the dough. Then, wrap a piece of foil around the parchment paper bundle to keep it in place.
Set the instant pot to manual, high pressure, and set the timer for 20 minutes.
Allow the seitan to cool then use two forks (or your hands if needed) to shred it into thin pieces.