Makes about 1.5 litres of fish stock.
- Before starting the recipe, place fish heads and bones in a saucepan full of water for an hour so that blood and impurities get drawn out. Then drain and rinse the fish heads and bones before returning them to the saucepan.
- Add the 2 litres of cold water to the saucepan and quickly bring to the boil. Immediately turn down the heat to a gentle simmer and skim off all the scum that has risen to the surface.
- Add the chopped onion and celery, the parsley stalks, bay leaves, peppercorns, fennel seeds.
- Squeeze the lemon wedges into the saucepan and then add them as well.
- Let the stock simmer gently for just 20 minutes. Check that is does not boil, and skim any further scum that comes to the surface. Do not leave it to cook longer than 20-30 minutes as that will make the stock go bitter.
- Strain into a bowl using a fine mesh sieve. Transfer the stock to smaller containers (250-500ml) suitable for storing the stock and allow to cool before covering with lids and placing in the fridge or freezer.
- Good fishmongers can usually provide bags of fish heads and bones fairly cheaply, on request, but you may need to ask in advance.
- If you have a spare coffee filter paper or new (completely unused!) J-cloth, then use it to line the sieve when you strain the stock. That will ensure you get the clearest stock possible – but if you don’t have either, then just use a fine mesh sieve. Obviously discard filter paper / J-cloth afterwards if you use it!
- You can store fish stock in the fridge (covered) for a few days, but it lasts a lot longer in the freezer.
- Use fish stock to add real depth of flavour to fish soups like this gorgeous Hot-smoked salmon chowder with whipped lemon cream.