beef stock

From the cookbook Gourmet Today
Makes 8 cups

2 lbs meaty beef shanks
2 lbs meaty veal shanks
2 onions, left unpeeled, quartered
1 carrot, quartered
4 parsley sprigs
1 thyme sprig
1 bay leaf
4 quarts cold water
2 celery ribs, quartered
1.5 tsp salt

Put a rack in the middle of the oven and preheat oven to 450 F.
Spread shanks, onions, and carrot in a large roasting pan. Roast, turning occasionally, about 1 hour.
With slotted spoon, transfer meat and vegetables to stockpot. Set roasting pan across 2 burners, add 2 cups water to pan, and deglaze by boiling over high heat, stirring and scraping up brown bits, for about 2 minutes. Add liquid to stockpot, along with remaining 3.5 quarts water, celery, salt, herbs, bring to a boil, and skim froth. Reduce heat and simmer gently, uncovered, skimming froth occasionally, until stock is reduced to about 8 cups, 3-5 hours.
Pour stock through sieve into a bowl; discard solids.