Bone broth is having a moment. If you haven't seen the stories touting its major health benefits as a digestive, bone, skin, hair, and anti-aging wonder, or fluttering over the cool kids drinking it out of paper cups, here's what you need to know, and more importantly, how to make it.
Is it broth or stock?
Technically it is stock, but bone broth is the buzzword of choice lately—it just sounds catchier and comfier than bone stock. Most people use the phrases interchangeably because the fundamentals are the same (simmering meat, bones, vegetables, and seasonings), but if you're cooking at home, there are subtle differences that make them distinct. The short version: A stock is reduced and concentrated from hours of simmering and used as a base for soups, stews, sauces, you name it. Stocks are only lightly seasoned because accents like salt and other spices intensify as a stock reduces and can overwhelm the flavor or compete with seasonings in the dish the stock is used in. A key difference: A good stock is viscous from the breakdown of collagen in the bones and cartilage and should gel when chilled. The health benefits are attributed to this gelatin richness. Broth is a soup in itself: a lighter, less gelatinous, and more highly seasoned liquid.
What you need to make it
We'll assume you have a cutting board, a sharp knife, and a wooden spoon. The other tools you need are a heavy-bottomed stockpot (preferably enameled steel or cast iron), a fine-mesh strainer or chinois lined with cheesecloth (you can also use cone-shaped coffee filters in a pinch), and freezer-safe storage containers like glass Mason jars or BPA-free plastic.
Hoard your scraps
Save everything. Onion tops and skins. The tough end of celery stalks. Carrot and tomato tops. Garlic ends. Bell pepper caps. Stems from plucked herbs. The produce you promised yourself you'd eat more of, but is now going limp in your crisper. Most vegetable scraps are fair game in a stock, with a few exceptions. Cabbage, Brussels sprouts, broccoli, and cauliflower (think: cruciferous neighborhood) or hot chile peppers can overwhelm the flavor of stock or turn bitter. Starchy vegetables like potatoes and corn will make the stock cloudy. Beets will turn your stock beet-red, and watery vegetables like cucumber or lettuces will disintegrate without adding much flavor. Collect all of your scraps in a one- or two-gallon zip-top freezer bag and freeze them until your stash is plentiful enough to use in a stock. Shoot for about 4 cups of miscellaneous veggies per 4 quarts of water.
Pile on the bones (and meat)
For the most robust, flavorful stock, use a hodgepodge of bones and meat: beef, chicken, turkey, veal, pork. Poultry skin and gnarly bits like gizzards, hearts, necks, feet, split hooves, and oxtails are also packed with flavor or cartilage that will yield more gelatin. Liver can turn a stock cloudy or bitter, so save that for another use. Aim for about 4 pounds of chicken parts and bones or 7 pounds of beef or pork bones per 4 quarts of water. Chop the bones and meat into 2-inch chunks to maximize the flavor.
Roast it all
If you're starting with raw ingredients (versus cooked scraps), thoroughly rinse the bones under cold running water, then roast the bones, meat, and vegetables in a 450°F oven or cook in the stockpot over medium-high heat until they are deeply browned, from 30 minutes to 1 hour. Roasting will always give your stock a richer, deeper flavor. Some pros also recommend slathering beef bones in tomato paste before roasting to amp up the flavor of a brown stock.
Always add vinegar
Use 1/4 cup or less of any vinegar—apple cider, white wine, malt—per 4 to 8 quarts of water. Adding a small amount to bone stock won't affect the flavor, but vinegar "helps extract minerals from the bone and vegetables, even when diluted with water," writes Sally Fallon Morell in Nourishing Broth: An Old-Fashioned Remedy for the Modern World (2014).
Lose the salt
Simmering a stock for hours concentrates the flavors in a big way, and adding salt on the front end of the cook could result in a too-salty liquid. Instead, season the final dish you use the stock in, such as a soup, sauce, risotto, or gravy.
Start with cold water
Combine the roasted ingredients and cold water in the stockpot and let them sit for up to 1 hour before slowly bringing the mixture to a simmer over medium heat. Starting from cold produces a clearer stock because the soluble proteins that escape from the meat and bones coagulate into bigger, easier-to-skim bits, according to food scientist Harold McGee in On Food and Cooking: The Science and Lore of the Kitchen.
Simmer, don't boil
Maintain a gentle, burbling simmer over medium heat for 12 to 24 hours, until the liquid has reduced and the bones are softened. A hard, rolling boil will obliterate the ingredients and produce a cloudy stock. Skim the surface of the stock often in the first 3 to 4 hours.
Make a raft
Straining the stock through a fine-mesh sieve or chinois lined with cheesecloth will filter out most of the loose particles. If you're making a clear soup (think: consommé) or the stock is too cloudy after straining, add 2 beaten egg whites and bring the stock to a low boil for 20 to 30 minutes. The set egg whites are a magnet for the fine particles floating in a stock. Cool the stock, gently remove the "raft" of egg whites at the top of the liquid with a slotted spoon or spatula, and strain again to remove any remaining egg white.
Colleen Rush is a food and travel writer who eats, drinks, cooks, and writes mostly in New Orleans, but also ... everywhere else. She is the author of "The Mere Mortal's Guide to Fine Dining" (Broadway Books, 2006), and coauthor of "Low & Slow: Master the Art of Barbecue in 5 Easy Lessons" (Running Press, 2009) and the upcoming "Low & Slow 2: The Art of Barbecue, Smoke Roasting, and Basic Curing" (Running Press, 2015). Follow her on Twitter or Instagram.