Once it’s finished, fish stock freezes well for up to three months.
The biggest difference between fish stock and other stocks is time: Fish stocks do not need hours and hours to come together the way beef or chicken stocks do.
Use lean fish like bass or cod – avoid oily fish like salmon or mackerel.
* 3 T. olive oil
* 3 lb. fish spines, fins and heads
* 1/2 of a large parsnip root, sliced into rounds
* 1 leek, sliced thin
* 2 stalks celery, sliced thin
* 1 carrot, sliced into thin rounds
* trimmings from a fennel bulb
* 1/2 cup sliced button mushrooms
* 1/2 bunch parsley
* 2 bay leaves
* 1 garlic clove, smashed
* 1 sprig of fresh thyme or 1 t. dried
* Cold water
Heat a large pan for 2 minutes on high heat, then add the oil.
Turn the heat down to medium and add the fish bones. You do not want them to brown, only to get a little color. Cook, stirring frequently, for about 5 minutes. Remove and set aside.
In a tall stockpot, add the fish bones and turn off the heat for now.
In the pan you sweated the fish bones in, add the vegetables and cook until the leeks are translucent. Stir frequently. When they are cooked but not browned (a little browning is OK), add them to the stockpot.
Add the herbs to the stockpot, stir everything to combine, and add enough cold water to cover it all by an inch.
Bring the stock up to a simmer. Do not let it boil. It is important that you don’t let it boil, because fish stock will get cloudy in a hurry if you do. Look for a shimmer on the surface, not burble.
Once the stock is at a simmer, move the pot off to one side of the burner a little. This will direct any impurities to one side, making it easier to skim. Simmer like this for 40 minutes.
After 40 minutes, strain the stock through a fine mesh strainer with a piece of cheescloth set inside. Clean the stockpot and then return the stock to the now-clean pot. Taste it.
Pour into plastic containers and freeze. Make sure you leave enough space at the top of the containers to account for the stock expanding when it freezes!