In a large stockpot, combine all the ingredients, adding more water if needed to cover by 1 inch (2.5 cm). Bring to a boil over medium-high heat. Reduce the heat to low and simmer gently, uncovered and without stirring, for 4 hours. Skim off any foam or scum from the surface at the beginning of cooking.
Strain the stock through a fine-mesh sieve set over a large bowl. Press on the solid