Bone Broth in the Slow Cooker

What bone broth is

Bone broth is stock made by simmering bones, usually with vegetables and herbs, for a long time. It is typically cooked longer than regular broth. Collagen from the bones breaks down into gelatin, so a good batch often turns jelly-like when chilled. A slow cooker is a convenient way to make it, because it holds a low, steady temperature for hours with little attention. Saving bones and vegetable scraps for broth is also one way to cut waste; see zero waste meal planning.

Ingredients

• 2 to 3 pounds of bones: chicken carcasses, backs, wings or feet, or beef bones such as knuckles, marrow bones and oxtail. A mix of meaty and joint bones tends to give good flavor and body.
• 1 to 2 tablespoons apple cider vinegar, which is commonly added in the hope of drawing more out of the bones. Its effect is not firmly established, but it does no harm.
• 1 onion, quartered, skin on is fine
• 2 carrots and 2 celery stalks, roughly chopped
• 2 to 4 cloves garlic
• A few peppercorns and a bay leaf
• Water to cover
• Salt, lightly, or none, and season later

How to make it

1. Roast the bones (optional). Roasting raw bones in a 400 degree F oven for 30 to 45 minutes gives a deeper, more savory flavor, especially with beef. For chicken, leftover roasted carcasses work well without extra roasting.
2. Add everything to the slow cooker. Place the bones, vinegar and vegetables in the pot and cover with cold water, leaving an inch or so below the rim.
3. Cook. Cover and cook on low until the broth tastes rich. Check your slow cooker manual for guidance on long unattended runs.
4. Strain. Remove the bones and use a fine mesh strainer to pour the broth into a large container.
5. Cool and skim. Chill it in the refrigerator, and lift off the fat that rises and hardens on top, or leave some for flavor.

How long, and should you use high or low?

Typical guidance is about 8 to 12 hours on low for chicken and about 12 to 24 hours for beef, though sources differ and there is no single correct answer. Low is the usual choice, since it gives a gentle simmer, a clearer broth and is easier to leave unattended. High is not necessary, but it can be used for the first hour or two to bring the pot up to temperature. Very long cooking can also leave bones crumbly and the broth tasting flat, so taste along the way and stop when it tastes good.

Cooling and storing safely

Large pots of hot liquid cool slowly, and bacteria can grow in the middle range of temperatures. To be safe:

• Strain the broth and divide it into smaller, shallow containers so it cools faster.
• Refrigerate within about two hours of finishing.
• Use refrigerated broth within about three to four days.
• Freeze for longer storage, in portions. Freeze in ice cube trays or muffin tins, then move the cubes to a freezer bag, so you can thaw just what you need.
• Always reheat until it is steaming hot.

Ways to use bone broth

• Sip it warm with a pinch of salt.
• Use it as a base in any soup, such as our slow cooker lentil soup or crockpot potato soup.
• Cook rice, grains or beans in it instead of water.
• Add a splash to sauces, gravies or braises.

You can find more ideas in our guide to easy crockpot soups.

Health questions, handled cautiously

Does bone broth lower cortisol? There is no strong evidence that bone broth lowers cortisol. Some websites suggest it, often pointing to the amino acid glycine, but this has not been well established in people. Enjoy it as a food, not a treatment.

Is there a downside to drinking it? Commercial and homemade broths can be high in sodium, so people watching salt intake may want to make it unsalted. Bones can also contain small amounts of lead or other contaminants in some analyses, though findings vary and amounts are generally low. Some people are sensitive to the histamine or glutamate in long-cooked broths. If you have a health condition, are pregnant, or are on a restricted diet, talk with your doctor or dietitian before making it a daily habit.

Claims that bone broth heals the gut or joints are common online, but the research is limited. It is best seen as a flavorful, comforting soup base.

FAQ

Can I reuse the bones? Some cooks make a second, weaker batch, but the flavor is usually thinner.

Why did my broth not gel? It may have had too much water, too few collagen-rich bones, or too short a cook time. It is still fine to use.

Is the fat okay to keep? Yes, a thin layer protects the broth in the fridge, and you can skim it off before using.