Method
Combine all ingredients in a large stockpot or Dutch oven, ensuring the cold water covers everything by at least 1 inch.
Place the pot over high heat and bring the liquid to a boil, then immediately reduce the heat to low to maintain a gentle simmer.
Simmer the broth for 4 to 6 hours, occasionally skimming off any foam or impurities that rise to the surface with a ladle.
Strain the broth through a fine-mesh sieve into a large clean pot or bowl, pressing gently on the solids to extract all the liquid.
Let the broth cool to room temperature, then refrigerate it until completely cold and the fat has solidified on the surface.
Skim off and discard the layer of solidified fat from the top of the chilled broth before using or storing.
Notes
Skim off foam for a clearer broth. The fat layer that solidifies after refrigeration is easy to remove.