Lobster Stock

We're having Lobster for Dinner and instead of throwing away the shells and bodies I decided to make Lobster stock, which I may use for Risotto ?

Ingredients:
4 pounds lobster shells and/or bodies
10 cups water
2 bay leaves
1/2 bunch fresh parsley
2 medium onions, finely chopped
2 large carrots, peeled and chopped
2 stalks celery, peeled and chopped
6 whole peppercorns
6 clove garlic, chopped
1 cup dry white wine
1/3 cup olive oil
3 tablespoons tomato paste
Salt to taste 

1. Put all the ingredients in a large pot and bring to boil. Reduce the heat and simmer gently for 30 minutes.
2. Remove the stock from the heat. Strain the mixture through cheesecloth.
3. Return the liquid to the stove and simmer until the liquid is reduced by half.
4. Let the stock cool down, then refrigerate or freeze.