Homemade Pork Stock

2 1/2 lb ham shanks or ham hocks

2 qts cold water

1 lg onion, chopped

2 carrots, cut crosswise into 1/2" thick slices

2 celery ribs, cut crosswise into 1/2" thick slices

3 lg garlic cloves, crushed

1 bay leaf

2 tsp dried thyme, crumbled

3 whole cloves

1/4 tsp black peppercorns

Combine ham shanks and cold water in a 4- to 5-quart heavy pot and bring to a boil, skimming any foam. Add remaining ingredients and simmer, partially covered, until shanks are tender, about 2 hours. Pour stock through a fine-mesh sieve into a large metal bowl, reserving shanks and discarding remaining solids.