Start with knuckle and marrow bones from grass fed beef. I happened to buy half of a cow from an acquaintance this fall and I requested from the butcher a bag of these bones. I just froze them until I was ready to make the stock.
Place the bones in a baking dish in order to roast them prior to making the stock. I cooked mine at 400 degrees for about 45 minutes.
I forgot to take a picture of them roasted, but you can see from the color of the pan, it browned them up nicely.
Place the bones in a large stock pot and cover well with filtered water. I believe I used about 15 cups of water for mine.
Add vegetables such as onions, carrots, and celery. There is not specific amount and you can use scraps that you have, but do not use leafy items such as cabbage. I included some garlic cloves and bay leaves as well. Finally, be sure to add a couple of tablespoons of apple cider vinegar. This will help draw out the nutrients from the bones. Bring to a boil and then simmer for 12-24 hours on low with a lid to prevent the liquid from evaporating out of the pot. I highly recommend going the full 24 hours because you'll get a much nicer final product.
Here is what it looked like after 24 hours...
And see the marrow bones? The marrow has been incorporated into the stock! This is what you want to see.
I strained my stock with a fine mesh strainer and poured it in two very large canning jars to cool in the refrigerator. Notice how the fat has risen to the top?
When it cools, the fat will be congealed enough to remove.
Simply take a spoon and scoop it out. You may wish to reserve this fat for cooking.
And this is when you realize you have a nice gel or not. Don't throw it out if you don't. It's still way better for you than the store bought stuff, but a gel means that you're getting a lot of that gelatin from the marrow bones.
Within a day or two, you'll want to use your stock or freeze it. To freeze, pour into labeled freezer bags (you may wish to measure it out and write the amount on the label - ie: two cups).
I also froze some in one cup sizes for recipes that don't require so much stock. These were not freezer bags, so I placed them inside a larger freezer bag.
For better freezer organization and for a quicker thaw, place the bags flat on a cookies sheet and freeze. Once they're hard, you can stand them up in a freezer basket or stack them nicely.
I hope this little tutorial helps some of you and I'd love to hear some additional tips from those who have been making beef stock for a while. Chime in with your thoughts!