I've made a few bone broths. I first gathered all the bones that came from my meats: mostly, beef but also some pork and lamb. Then I discovered big marrow bones. I put some vinegar and boil until the marrow is dissolved from the core and the bone becomes hollow. That, I believe, is the "essence" of the bone broth, right?
What then is the point of the smaller bones, like ribs, etc. Their cores do not disappear and even after repeated boiling, I don't know if anything is coming out. Should I even bother with these non-marrow bones?
Why not buy like 4 marrow bones (which are cheap) and be done with the bone broth? What am I missing?
what you're missing is roasting your marrow bones for a bit and eating them with some chopped parsley and sea salt. If they're not sawed in half you can essentially pop the fat out by running a knife along the side and tapping the roasted bone against your plate until the marrow pops out. I'm not sure i'd have the heart to throw a real marrow bone into stock anymore. It's just too damn good roasted.
When bones are softened they dissolve into the broth... not all of the 'good stuff' in bone broth is from the marrow. But you have to use a variety of bones for to get this result. I love beef broth but I don't do it as often, chicken is much easier. Although I do LOVE oxtail soup, and the cartilage is easy to dissolve for a nutrient dense and tasty broth.
Aside from the marrow, when making bone broth you are extracting vitamins and minerals from the bones, and there are usually bits of meat or connective tissue and/or collagen attached to the bones that can dissolve into gelatin. To me the sign of a good bone broth is when it becomes gelatinous when cooled.
When I make broth/stock from chickens or other fowl, I throw the whole carcass in the water which includes skin, cartildge, bits of meat, etc. Thiz makes the broth more flavorful and nutritious.
I don't use any bones or scraps more than once because after boiling for an hour or two, I don't think there is enough food value left to be worth it.
So to answee your question, the small bones are worth including even if they aren't full of visible marrow.
I'd say throw the smaller bones in simply for their added mineral content. Also, in addition to marrow, there is "bone grease". Even bone that appears solid is a latticework of bone tissue, and within the pockets of this are tiny globules of fat. Smash those bones up with a hammer or sledge, and then throw them into your stockpot- you'll extract much more fat from within the bone itself, and not just the marrow.
I left a lamb breast in my crock pot for about 30 hours, and the bones were chewable. Another few hours they could easily be blended into a palatable supplement. I didn't care for chewing on them too much, kinda gritty. I ate a few just because I know they're good for me.
If there are enough bones, and you cook for long enough, see if the stock "gels" when cooled and refrigerated. If it does - then you know you've got really good stuff in there.
Even the stock from a gammon ham (no bones) can gel if the stock is rich enough. All good for you. Marrow is NOT the only nourishing thing in bones!