Add all ingredients to a stock pot or a crock pot.
Simmer on low for as long as your schedule allows, 6-12 hours is ideal for already cooked bones, raw bones can cook much longer, even 24 hours. Broth should not come to a full boil, but just barely a simmer: 75°F to 200°F or 80°C to 90°C is sufficient.
After simmering, when the broth has cooled a bit, set a large bowl (preferably one with a pour spout such as a very large measuring container) in your sink and rest a strainer/sieve inside of it. Pour the broth through the strainer and into the bowl.
Remove the sieve and it’s contents.
Pour broth into containers, I prefer half gallon glass jars. When it has cooled to ‘warm to the touch’ place it in the refrigerator and use within the next week. Alternatively, store in silicone cube trays or zip lock bags and freeze for future use.