How to Make It
In a large (8 quart) pressure cooker, combine all of the ingredients with 2 quarts of water. Close and seal the pressure cooker and bring it to full pressure over high heat. (This may take 10 minutes or more.) Reduce the heat to low or just high enough to maintain full pressure and cook for 30 minutes. Release the steam according to the manufacturer's instructions.
Slowly pour the stock through a fine strainer into a large heatproof bowl, leaving behind any particles at the bottom of the pot; press lightly on the solids to extract the liquid. If necessary, return the stock to the cleaned pot and boil until reduced to 2 quarts. Let cool completely before refrigerating.