MAKES 2 QUARTS/2 L
If desired, sauté the onion, leek, and celery in 1 tablespoon of olive oil until soft and aromatic before adding the other ingredients. For a more concentrated caldo, gently simmer uncovered for 1½> hours.
In a stockpot or another large pot, begin heating 8% cups/2.1 L water over high heat. As the water heats, add the fish, onion, leek, celery, and peppercorns; pour in the wine; and season with salt. Once it reaches a boil, reduce the heat to medium-low, partly cover the pot, and simmer for about 30 minutes, skimming any foam that floats to the surface.
Remove the pot from the heat; add the bay leaf, thyme, and parsley; and infuse for 20 minutes as the stock cools. Strain the broth through a conical strainer. Gently press out the remaining liquid from the fish and vegetables, and discard the solids.
Store in the refrigerator for up to 3 days or freeze for up to 3 months.