For longer than there have been kitchens, people have found ways to boil bones. From rural villages to urban restaurants to grandma's house, the virtues of bone stock, and its salted cousin broth, are hardly a secret. But lately, bone broth has boomed into trend. You can pay nearly 10 bucks for ginger grassfed beef broth at Brodo in New York. You can drink it at the Jola Cafe in Portland, Ore. It's available online to be shipped fresh to your doorstep.
Even Los Angeles Lakers star Kobe Bryant credits regular consumption of bone broth for helping him recover from some serious recent injuries. In fact, according to the Washington Post, practically the whole team has been on bone juice since the 2012/2013 season.
If you've ever been lifted from the depths of exhaustion, hunger, illness or chills by a sip of warm broth, you might be inclined to believe in such restorative powers.
There are many variations on bone broth, with a diversity of finished outcomes attached to each. Vietnamese pho, made from cow bones, is very different from Japanese tonkotsu ramen broth made from pork bone or veal bone-based demi-glace in a fancy French restaurant, or Mom-style chicken bone soup. Thus, I'll leave you with, not a recipe, but:
At its bare essence, making bone broth entails little more than cooking bones in hot water for 12-36 hours.
A slow cooker is a great brothing device for many reasons. Using one isn't as dangerous as leaving a stove burner on for days at a time, and the broth cooks slowly enough that you don't need to keep adding water. It's very convenient to have a crock-pot going at all times with broth that's at the perfect sipping temperature, and available to be used in whatever's cooking. If the stir-fry is drying out, add a ladle of broth. Looking to make a soup or sauce? Use broth as a base.
The bones should be cut, which releases the marrow and other inner bone materials, and allows more surface area to contact the broth. When I make stock with the bones of a store-roasted chicken, I use scissors to snip the soft bones to bits. With mammal long bones, ideally the butcher will cut them, otherwise cut them at home, or whack them with a hammer.
If whacking the bones, make sure that the resulting bone splinters don't enter anyone's mouth—unless cooked to absolute softness. Some people simmer their bones in a fine mesh bag to keep them out or pour the finished broth through a sieve. In my case the broth just sits in warm mode in the crock-pot. The bones settle, and as long as I use a ladle to serve it, there's no danger of bone fragments.
For best flavor, begin by roasting the bones in the broiler, turning them as necessary, aiming to brown but not burn. Add the bones to the stock pot, and make sure to deglaze and scrape the roasted bone drippings into the pot as well. Cook on the lowest setting you've got.
After about 12 hours, consider adding carrots, onions and celery. Don't get too fancy with your veggies; broccoli and cabbage will backfire if cooked too long, so use these and other calcium-rich veggies to make soup with after the broth is done.
Leave the broth unsalted in the pot until it's time to use it. Then, season appropriately. If sipping, I like a splash of soy and a sprinkle of garlic powder.