Making stock is a good way to make your food purchases go further. Using bones that are not themselves edible but which contain flavour and nutrients can stretch the benefits and show additional respect for the animal that you eat.
There are a couple of different approaches you can take when preparing soup or stock from bones. The one I’ve used longest takes advantage of the carcass of a bird or joint that has been baked or roasted in the oven. I remove as much meat as I can from the bones before simmering them for maybe an hour, maybe longer, until it smells really good, the liquid has a bit of colour and the bones are falling apart. I then freeze the stock in pints until it’s needed. Over the years, I’ve learned that any scraps of meat that stuck to the bones before the simmering aren’t worth saving afterwards: they’ll have given up all their nutrients to the stock, and their texture will be stringy at best. You have to be pretty hungry to be willing to spend the time carefully separating scrawny twice-cooked meat fibres from a bird’s rib cage for just an appearance of meat in your next meal. So now I strain this kind of stock and discard the meat and any other solids along with the bones.
Sometimes, I have a carcass that hasn’t been cooked, such as when the breast has been taken off the bone for my Christmas goose recipe. In this case, I actually roast the bones on their own for enhanced colour and flavour, then proceed as above.
No matter what kind of stock I’m making, I normally include a bay leaf or two, and some solid spices that I think will complement the meat essence, but never salt. It’s better to add salt as late as possible when actually using the stock. There will also be some flavour from whatever I cooked the meat with the first time around. I’ve also learned that you get better flavour if you don’t start with too much water–use only enough to cover the bones, crushed if you can. And then don’t simmer so long that the water all evaporates!