Bone broth comes from simmering animal bones in water for an extended period, typically anywhere from 4 to 24 hours. The slow cooking breaks down the bone matrix, releasing collagen, gelatin, and minerals like calcium, magnesium, and phosphorus into the liquid. Beef, chicken, pork, and fish bones are the most common sources, and the practice of making broth from bones is likely as old as cooking itself.
What Bones Are Actually Used
Almost any animal bone can become bone broth, but certain types yield better results. Beef bones, particularly from the femur and tibia (the large leg bones), are rich in collagen and marrow. Research on bovine bone has found that tibias produce higher collagen yields than femurs, and bones from younger animals release more collagen than those from older ones, which contain higher levels of minerals and proteoglycans instead.
Chicken carcasses, including the back, neck, and feet, are another popular choice. Chicken feet are especially prized because they’re packed with connective tissue that breaks down into gelatin, giving the broth a thick, almost jiggly texture when cooled. Pork neck bones and knuckles serve a similar role. Fish heads, spines, and frames work too, though fish bone broth cooks much faster, often in under two hours, because the bones are smaller and less dense.
The joints, cartilage, and connective tissue matter just as much as the bones themselves. Knuckles, oxtails, and marrow bones all contribute to a richer final product because they contain more of the proteins that dissolve during long cooking. Marrow, the soft fatty tissue inside larger bones, melts into the liquid and adds a small amount of fat (roughly half a gram per cup in a typical broth).
How Bones Become Broth
The process is straightforward: bones go into a pot of water with vegetables (usually onion, carrot, and celery), herbs, and a splash of something acidic like apple cider vinegar. That acid is doing real work. It helps draw collagen, gelatin, and minerals out of the bone matrix more efficiently, boosting the protein and mineral content of the finished broth. Most recipes call for just a tablespoon or two of vinegar per batch.
Time is the key variable. A standard meat broth simmers for a short stretch, maybe an hour or two, and relies on the meat itself for flavor. Stock simmers longer with bones and produces a thicker, more gelatinous liquid. Bone broth is essentially stock taken to the extreme: the same bones-and-water foundation, but cooked for many hours (sometimes a full day) to extract as much collagen and flavor as possible. Despite the different names and price tags, bone broth and a well-made stock are fundamentally the same thing.
You can tell a good bone broth by its texture. When refrigerated, it should set up like gelatin. That wobble is dissolved collagen, and it’s the main thing separating a rich bone broth from a thin, watery one.
A Practice as Old as Cooking
Early hunter-gatherers almost certainly made bone broth, or something close to it. When food was scarce, tossing bones, scraps, and whatever vegetables were available into water over a fire was a way to extract every possible calorie and nutrient from a kill. Nothing was wasted. The resulting liquid provided hydration, warmth, and minerals that were hard to get otherwise.
That resourcefulness carried forward into nearly every food culture on the planet. In Japan, pork and chicken bones form the base of ramen. In Jewish tradition, chicken soup made from a slow-simmered carcass earned the nickname “Jewish penicillin” for its reputation as a cold remedy. Caribbean cooking features cow foot soup, a hearty bone-based broth believed to build strength. Across many African cultures, bone broth anchors soups and stews as a staple of everyday nourishment. In Chinese medicine, bone broth has been used specifically to support bones, cartilage, and connective tissues.
In colder European climates, families stretched their food supply through winter by boiling beef and lamb bones into broths that served as the foundation for soups and stews. The theme is consistent across continents: bone broth emerged wherever people cooked animals and wanted to use every part.
One Thing Worth Knowing About Lead
Bones store minerals, but they also store lead. A controlled study on organic chicken broth found that both chicken-bone broth and broth made from skin and cartilage contained several times more lead than the tap water used to make them. Chicken-bone broth measured 7.01 micrograms of lead per liter, and broth from skin and cartilage reached 9.5 micrograms per liter, compared to 0.89 for the plain water control.
These concentrations are low in absolute terms, and occasional consumption is not a recognized health concern for most people. But if you drink bone broth daily or give it to young children, the cumulative exposure is worth considering. Sourcing bones from pasture-raised animals and avoiding very long cook times can help keep levels lower, though no preparation method eliminates lead entirely.