Rinse chicken and add to a large stockpot with neck and organs. Add onion, garlic and ginger to pot. Cut celery and carrots into 3 or 4 large chunks and place on top of chicken. Add mushrooms and burdock if using. Add seaweed and vinegar and cover with water. Cover and turn heat to medium high to bring broth to a low boil. Reduce heat to simmer and cook for 2 hours.

Then remove chicken from the pot and pull meat from the bones. Add skin and bones back to the broth and simmer broth for an additional 16-24 hours. Refrigerate chicken for use in soups, salads, etc.

Strain broth into a large bowl using a fine mesh sieve and then add to glass mason jars or containers and refrigerate. If desired, remove fat that congeals on the surface of broth before using. Broth should congeal to a jelly like texture when refrigerated. Use within 3-4 days or freeze in glass containers.