Place all ingredients in a stock pot and cover with water.
Place pot on medium heat. Bring to a slight boil then immediately turn down the heat to low and simmer for 2-3 hours.
Do not allow the vegetables to roll and touch each other. The slower the better.
Allow broth to cool.
Strain through a sieve. Strain again through a coffee filter.
Notes
Note: You can try this in an Instantpot but the temperature and water movement you want is a slow simmer - not a full simmer and not a slow-cook. Keep playing with your technique. You may decide you are OK with your results!! :-)