I basically follow the instructions in Professional Cooking (Gisslen's book).
For every 10-12 lbs of browned bones, I brown a mirepoix of 1 lb of onions, 1/2 lbs carrots, and 1/2 lbs of celery (all diced).
It took me all day to brown 44 lbs of bones. I divided them evenly into two 20-22 qt stock pots (one allclad, the other narrower in diameter but taller from a restaurant supply house).
I cover the bones with water, and simmer gently (a very few bubbles). While this is started, I brown the mirepoix in the same baking pans as the bones so the water from the veggies picks up the browned bits from the bones. Halfway through the 10-12 hours of simmering the stock, I add the mirepoix, and I use a strainer skimmer to remove the grudge from the surface.
I keep adding water, per instructions, to keep the bones covered.
Then I remove the bones (they're heavy), and then use a fine china hat to sieve the stock. That is when the chinois tipped over on me. (Yeah, I'm not burned, got to the clinic licketty split...thanks for asking!)
So, once its all strained, the wife steps in and starts filling quarts and canning them. That is why I never bothered to count.
I figure roughly i get somewhere between 16-19 qts of stock if nothing goes wrong.
I only got 15 this time, so I must have spilled 1-3 qts on me.
$66 for the bones, a few more $ for the veggies, $$$ for the electricity, and $/2 for the gas cooktop.
Stock is deep in color, tastes like all the stocks I've made. Forgot to mention I add a tomato product usually some paste on the bones when they're almost browned to the point I'm looking for.
I use the stock whenever a recipe calls for beef or veal stock. (I also have turkey stock for whenever a recipe calls for chicken or fowl stock.)
I also make Espagnole sauce as an intermediate to making demi-glace strictly per Escoffier.
So this time I'm gonna take all 15 qts plus 5 more from May, 2008, and make a double batch of demi. I should end up with 32 cups of outstanding demi.
First time I'm gonna double the process. (Wife wants the quarts back, we used too many to can tomato puree this summer).