Begin by roasting the meat bones. Preheat the oven to 450° F. Place bones on a large sheet pan and roast for 30 minutes.
When finished roasting, place bones in a roaster oven. Scrape all of the little meat bits and juices into the roaster with the bones.
Add ¼ cup apple cider vinegar.
Add the onions, garlic, and black pepper.
Fill the roaster ⅔ full of water covering the bones. (approximately 2 gallons).
Allow this to soak for 1 hour with no heat to start the process of extracting the nutrients.
After 1 hour turn the heat to 175° F. Adjust to 200° F after 1 hour of cooking.
Cook for 24 hours.
Turn off the heat and preserve.