2-3 pounds bones of grass-fed beef or organic/pastured chicken (raw or cooked leftovers)

4 L filtered water

2 tablespoons apple cider vinegar

1 large onion, coarsely chopped

2 carrots, peeled and coarsely chopped

3 celery stalks, coarsely chopped

1. Place bones in a stock pot or crock pot and fill with water (bones should be mostly submerged)
2. Add vinegar and all vegetables except parsley to the water.
3. Bring to a boil, and remove any scum that rises to the top.
4. Reduce the heat to the lowest setting and let simmer.
5. If bones have meat and/or marrow in them, these will start to separate from the bones after a few hours. You can help separate the meat and marrow from the bones every couple hours.
6. Simmer for 12-24 hours.
7. Remove remaining bones from the broth and strain the rest through a strainer to remove anybone fragments.