Stocks and broths are one of the oldest forms of cooking. They enabled ancient humans to maximize the yield of animal proteins and vegetables by simmering them in water, effectively extracting nutrients that would ordinarily be unavailable through simpler forms of cooking. Anthropology and food chemistry aside, stocks and broths are satisfying to consume because they are warm and taste complex. This recipe will describe how to prepare beef stock. It’s perfect for French onion soup or as a base for other soups. Many of the techniques used here are transferable to what you’d need to know to make chicken, vegetable or seafood stock (and countless others). This recipe yields about 5 quarts of stock, but feel free to customize the recipe or freeze your leftovers!

Ingredients 

• 5 pounds untrimmed beef bones, including cuts of knuckle and exposed marrow (Pro tip: Try to find shanks neckpieces or other pieces with connective tissue, and if you can’t find knucklebones, substitute with some chicken wings; I recommend going to your local butcher — and look forward to a nod of approval once you request these ingredients) 
• 1 pound beef stew meat (you can look for veal neck and/or splurge for short ribs or oxtail)
• 1/2 pound mushrooms
• 1 large carrot
• 2 large onions
• 2 ribs celery 
• 1 bulb garlic
• 1 bunch parsley
• Handful of thyme sprigs
• 2 to 3 bay leaves
• Tomato paste
• Cooking oil (canola or vegetable, not olive)
• Handful of whole peppercorns
• Red wine (optional, but recommended)

Directions

1. Preheat your oven to 425 degrees Fahrenheit with the rack in the middle and convection on.
2. Roughly chop the carrots into a few pieces, and quarter the onions. Slice the mushrooms in half. It’s OK to leave the roots, peels and stems on — minimize food waste and maximize flavor!
3. Place the beef bones, stew meat, carrots, onions and mushrooms onto a baking tray, and smear everything in tomato paste. Lightly drizzle some oil over everything.
4. Roast all that goodness for about an hour or more, keeping an eye out and flipping everything at 30-minute intervals so that nothing burns. Remove from the oven once everything is deeply browned.
5. Slice the head of garlic lengthwise so that all the cloves are exposed. Roughly chop the celery into a few pieces, and collect your parsley, thyme sprigs, bay leaves and peppercorns. 
6. Place everything in a large stockpot. No biggie if you don’t have one massive pot. You can use multiple pots — just be sure that all your ingredients are evenly distributed between them.
7. Pour some red wine or water on the mostly empty baking trays while they are still hot, and aggressively scrape with a wooden spoon. Collect all those browned bits stuck to the pan, and pour the mixture into your stockpot. 
8. Add enough cool water to cover everything, and place over a stovetop set to medium heat.
9. Making stock is very much a low and slow process. Keep an eye on things as your stock heats up, and don’t let it completely boil. Your goal is to see a few small bubbles here and there with stray wisps of steam emanating from the top of the liquid.
10. During the first hour or so of cooking, skim off any foam or particles that float to the top.
11. Stir occasionally and let the stock simmer for 5 to 8 hours. There’s not really an exact prescription for this step. Your gauge is whether the cartilage on the bones has melted off and the vegetables are completely softened. If you’re unsure, taste a small piece of beef. It should have a pallid gray appearance, fall apart easily and have no taste — this means all of its color, nutrients and flavor has been extracted into your stock.
12. Strain everything through a fine-mesh strainer, and once again through cheesecloth if you have one. 
13. Your stock needs to cool before you store it. You will warm up everything in your fridge or freezer if you put a pot of nearly boiling liquid inside. Prepare an ice bath for your pot of stock to rest in for 15 to 20 minutes until tepid. Store in the fridge overnight.
14. The next day, you should see a layer of fat that’s risen to the surface. Skim that off, and discard.

Your stock is basically done at this point! You can refrigerate your stock for up to 5 days or freeze it for up to 3 months. I recommend freezing stock in ice cube trays and then storing the cubes in a big Ziploc bag for easy usage. You might be wondering why this recipe doesn’t call for seasoning with salt. It’s important to not season with salt until the very end since you have no way of knowing what level your stock is going to reduce down to. You can always add more salt, but once it’s in there, you can’t take it away. Season to taste either at the very end of the stock-making process — or better yet, season each individual dish you choose to make with your homemade beef stock. Enjoy!