Rinse the fish bones under cold running water.
Heat the olive oil in a large pot over medium heat. Add the onion and cook for 2 minutes, then stir in the carrot and celery. Cook for a further 3-4 minutes or until the onion and leek are soft. Add the fish bones and heads, bay leaf, parsley and peppercorns and cook for 2-3 minutes, then pour over the white wine. Cook for 2 minutes then add the water and salt to taste. Reduce the heat to low and simmer for 1.5 hours.
Remove from the heat. Strain the fish stock through a fine sieve into a bowl, using the back of the ladle to extract as much flavour as possible. If not used within 1 hour, refrigerate the fish stock.
Use fish stock in your favourite Italian dish. We recommend you try Cacciucco alla Livornese (Livorno-style fish stew) or Risotto ‘alla Pescatora’ (Fisherman-style risotto with seafood) – buon appetito.
Fish stock (brodo di pesce) can be refrigerated for up to 3 days. I also like to prepare it in advance and freeze in 500ml portions for up to 2 months. They can then be defrosted and used as needed.