Prepare the bones: Place all beef bones in a slow cooker or large stockpot. Add apple cider vinegar and enough purified water to cover the bones by about 1 inch.
Simmer gently: Cover the pot with a tight-fitting lid. Bring water to a gentle simmer over medium heat—never boil. Skim off any foam or scum that rises to the top using a shallow spoon. (If using a slow cooker, wait 2 hours for the water to warm before skimming.)
Add vegetables and herbs: Add carrots, celery, onions, parsnips, leeks, sage, bay leaves, thyme, rosemary, salt, peppercorns, garlic, fennel seeds, caraway seeds, fennel bulb, ginger, and turmeric. Reduce heat to low, keeping the broth at a barely simmering temperature.
Cook long and slow: Simmer for at least 12 hours and up to 24 hours, skimming occasionally during the first 2 hours. Add water as needed to keep bones fully submerged.
Strain the broth: Remove bones with tongs or a slotted spoon. Pour broth through a fine mesh strainer and discard solids.
Cool and store: Let broth cool on the counter, then refrigerate within 1 hour. Skim off fat once chilled if desired. Broth should become gelatinous when cold.
Storage: Keep in the refrigerator for up to 5 days or freeze for 3+ months in wide-mouth jars.