Taking stock: fish and shellfish

Categories: Expert guidance

Tim Maddams tells us why we should get back to making traditional stocks and broths from scratch—and shares his tips and tricks on how to do so. This time: fish and shellfish

Fish. One of our most precious resources. Getting hold of fresh fish at Borough Market has never been a problem—the helpful and cheery experts behind the counters are always happy to help, so you can guarantee you are in for a fishy treat. But how often do we make the most of the bones?

It is no coincidence that classical French cookery is littered with fish dishes that are cooked on the bone. So much of the flavour is contained within those translucent skeletal shards—flavour that is given up to the sweet salty flesh when you add heat. Fish stock, then, is a very useful thing for any busy, fish-eating household kitchen. It is thrifty as well—when you are sold a whole fish, even if it has been filleted, you have paid for the bones so make sure you ask for them and take them home with you to make a stock.

Tradition in the UK dictates that stocks never be made with oily fish or bass bones. Both of these myths have a grain of truth, but I think we can safely discard these as concrete rules to follow. Let’s use mackerel as an example of an oily fish. No, you cannot make a light, fresh and tasty fumé style fish stock with its bones, but you can include them in a more robust, dark and spicy fish stock, or even in a super-fast Asian style stock with lots of lemongrass, ginger, soy and chilli. Bass bones have something to offer in terms of flavour and can be used for stock, but I would advise mixing them with the bones or ‘frames’ of other fish to counteract any bitterness.

There are, effectively, two types of fish stock: light and dark. But then we must also consider shellfish—crab and lobster are famous for their rich and aromatic stocks. For this episode, I will talk you through all three, to cover all the angles. I will also make some suggestions as to what to use your stocks for and offer a few recipes that are made to measure.

Light fish stock
A light fish stock can be made by cooking white fish bones—with all gills and bloodlines removed—on a low heat along with a few tbsp light olive oil, 1 or 2 peeled onions, a stick of celery, a fresh bay leaf, a few white peppercorns and a little thyme, garlic and salt. Once the ingredients begin to soften in the pan, add a glass or two of dry white wine, a little white vermouth, or even anise—pernod or pastis, for example. At this stage it is very important to trust your nose—you must wait for the liqueur to lose its raw, acidic notes before adding just enough cold water to cover the bones and aromatics. If you do not allow the wine to ‘cook out’, you will trap a bitter, acidic note inside the stock that is very hard to get rid of and is rather undesirable—like a hangover.

Once the water is in the pan, the stock must be brought to a simmer very, very gently and any impurities, foam, scum and so on must be removed to keep the fresh and vibrant, light and airy fish scent untarnished, captured within a glintingly clear, bright liquid. Once at a simmer, the stock should cook for no more than 40 mins as after this time, and maybe in less, the bones will begin to dissolve, leaving the stock bitter and possibly even gritty.

Allow the stock to cool a little and settle, then pass it off through a fine sieve—purists will make sure that the stock is drained one ladle at a time, so as not to disturb the sediment that has settled. I will leave that choice up to you. Once cooled, the stock can be kept refrigerated or frozen until needed and will stay fresh in the fridge for a few days. However, it will continually lose quality, so best to make use of it as soon as possible.

This stock is excellent as a base for white fish sauces like veloutés, made either with a roux or by adding cream and reducing. It also makes an excellent base for fish risottos—or, my particular favourite, green soups like watercress, parsley or wild garlic. You can also use it in place of milk in recipes for fish pie, or in a lovely fish soup. I also quite like to make risotto or a simple broth by just adding a few things from the veg cupboard to the hot stock.

Dark fish stock
This is very much everything that a light fish stock is not. Rich, brassy, full of vim—gruff where light stock is delicate. It's a bully on the palate and not for the feint-hearted. You will find a version of this stock served as a spicy fish soup or stew in most coastal areas.

The bones for this stock do not need to be carefully trimmed—you can sling the heads in the pot without worrying about the gills too much. You want the pan hot to start the process. Again, use a little light olive oil to get colour onto your veg and your fish bones. I also add tomato paste or super ripe or tinned tomatoes, along with paprika, fennel seeds and chilli before adding the wine—I sometimes go so far as to add carrot along with the onion and fennel, and I may well leave the skin on the onions. Really roast the bones and veg until almost catching on the bottom of the pan, before adding the white wine or anise, as for the lighter stock. Again, it is important to cook out the alcohol before adding cold water.

You can bring this rumbustious, flavoursome rascal of a stock to the simmer much quicker than a light stock and have a devil-may-care approach to skimming off impurities. And, unlike a light or white fish stock, you can add extras as you go along—maybe some harissa paste, or extra fish bones, that sort of thing. This bold and flavoursome brew can be cooked for a lot longer, but do taste it from time to time as you may end up with bitter notes if you go on cooking it for too long.

This makes an excellent base for spicy fish stews like chipirones al romesco, or simply make up your own—maybe season and fry some fish chunks, add a little of the stock, simmer and then serve with a spicy mayonnaise-type sauce, some croutons and grated cheese. I also love to make a fishy lasagne, using this stock to make the thickened sauce for the pasta—a very unusual but punchy version.

Shellfish stock
Whether you are using prawn, lobster or crab shells, I thoroughly recommend roasting them in the oven with a little oil to get the flavour really rolling before adding to your stock pan, with all the lovely fennel, onion, carrot, fennel seeds and tomato paste already cooking. Add the roasted shells and only then add the wine—once again, you must cook this out thoroughly before adding cold water.

Bring the stock to a slow rolling boil this time, rather than a steady simmer as before. This will need to cook for at least 4 hours and you may need to top up the liquid from time to time, to keep it just on a level with the shells and the veg. Once cooked, allow the stock to cool a little ‘on the shells’ before passing off.

Again, you can use this stock for all sorts of rich and deeply umami dishes—I love to reduce it until it is quite thick and then beat it into mashed potatoes, egg yolks and olive oil, then use the resultant mixture to pipe onto crab shells filled with the picked meat. This is then grilled or baked until golden and piping hot and served with a very cold English white wine—heaven. Another good use for this is fisherman’s stew, where it would add a very different tone to the dish in place of the light fish stock. Another hit in my house is to add some of this stock, reduced almost to a syrup, to a marie rosé sauce for a fairly revolutionary prawn cocktail.

Though there are some reasonable fresh and dried vegetable and meat stocks available in the world at large, there is nothing that comes even close to a decent homemade fish stock. Here, more perhaps than anywhere else in the world of stock, there is no room for impersonation—freshly made, properly put together fish stock is the only thing that will do. Ever.