Break and crack the bones of the carcasses.
Heat the vegetable oil in a 6-quart stockpot over medium-high heat. Season the bones with 1 teaspoon of the salt and the black pepper. Add the bones to the pot and brown for about 10 minutes, stirring often.
Add the carrots, celery, onions, garlic, bay leaves, and the remaining teaspoon salt. Cook until the vegetables are soft, about 5 minutes, stirring often.
Add the wine and tomato paste and stir to mix. Cook for 5 minutes, stirring occasionally. Add the water. Put the thyme, tarragon, and parsley sprigs in a piece of cheesecloth, tie it together with kitchen twine, and add it to the mixture. Add the peppercorns and bring the mixture to a boil. Skim off any cloudy scum that rises to the surface. Reduce the heat to a medium and simmer, uncovered, for 3 hours.
Strain through a fine-mesh strainer and cool. Refrigerate overnight and remove any congealed fat from the surface. The stock can be stored in the freezer for 1 month.
Yield: 4 cups