Marinating is an incredibly simple way to add flavour to fish. You can do it with raw fish, using a cold marinade - a technique that generally works best with white fish. Alternatively, you can bathe cooked fish in a hot marinade to get a quite different result - usually best with oily fish.
There are a couple of classic dishes, both South American in origin, which make the most of these techniques and I frequently turn out a version of one or both of them at home. They share two particularly attractive characteristics: first, they can be excellent make-ahead dishes, which don't rely on split-second timing. Secondly, they're just begging to be tweaked and tinkered with, depending on the ingredients you have to hand.
Cold marinating: ceviche
Cold marinating can be as simple as tossing chopped or sliced super-fresh raw fish with a few aromatic flavourings and herbs - maybe olive oil, Tabasco, parsley, chopped red onion - and serving it up as a kind of fish ‘tartare'. However, I nearly always include some citrus juice in a cold marinade and, as soon as I do that, I am entering the exciting realms of ‘ceviche'.
Ceviche is a way of ‘cooking' fish, but without heat. It relies, instead, on the chemical properties of citric acids which in the case of ceviche means a delicious marinade of lemon, lime and orange juices. When you immerse fish flesh in these juices, there's an almost immediate visible chemical reaction. As the acid is absorbed, the translucent flesh becomes opaque and milky (just as it does when you heat it).
Ceviche celebrates the natural textures and flavours of good fresh fish, without being quite as hardcore an experience as eating sashimi or sushi. If you find totally raw Japanese-style fish preparation just too alien, but like the idea of eating fish in its natural state, ceviche is definitely worth a try.
Firm, white-fleshed fish, such as black bream, bass, pouting, whiting and pollack, work best. I'd certainly consider using salmon or trout too. But really oily fish like mackerel, while they can make an interesting addition, don't tend to work as a main ingredient. Ceviche is often made with a mixture of fish species but it's equally good with just one type.
You can vary the amount of time you allow the fish to marinate before you eat it. When I first started making ceviche, I would leave it for an hour at least. Over the years, my marinade time has got shorter and shorter, and quite often now I'll just prepare it and eat it straight away - especially if I've made it with some eye-wateringly fresh bass or black bream, because I can't keep my hands off it.
It's actually perfectly safe to keep your marinated fish in the fridge and eat it the next day, when you'll find the texture much softer and less ‘raw'. But my own preference is for a just-marinated fresh, zingy, crunchy experience.
Hot marinating: escabeche
When I find myself looking for something a little different to do with oily fish, such as mackerel, herring or garfish, and I have a little bit of time on my hands, I'll plump for the hot marinade option. While this involves cooking the fish, the final dish itself is served at room temperature. It's a great recipe for using up a glut of oily fish, and it's perfect for a large group of fish diners. Or as a tapas-style dish, served alongside other delicious fish treats.
All I do is fillet the fish then fry the fillets quickly over a fairly high heat to give them some colour on the flesh side and just a little crispy edge. I might dip the fillets in flour first too so they'll have an extra crispy coating - this crispness works well with the marinade as it soaks up the flavours a little more than the flesh alone might do. Over these cooked fillets I'll then pour a hot and fragrant marinade: a mix of, say, vinegar and apple juice, spiked with garlic, shallots, grated ginger, lemon zest and chilli.
The fish will then be left to cool in its aromatic bath, and I'll serve it later with some good crusty bread to soak up the juices. A dish like this is great to make in advance because it actually improves with being chilled for a day, although I always serve it at room temperature, never cold.
What I'm describing in my ad hoc way is actually a Latin American classic called escabeche. Like ceviche, it exists in many forms, so you should feel totally at liberty to create your own version.
For my money, it's a great way to use up an excess of oily fish. I'll often use it on a few skinny, sad mackerel that I've got left after a barbecue, or with the results of filleting accidents. I'll even do it with bony fish like sprats or small herring or garfish, where the bones are too tiny to remove without a full surgical team as back-up.
In this case, I'll fry the fish hard, cranking the oil up a few degrees and crisping them good and proper. This way, the bones, fins and skin become crunchy, and the marinade soaks into them deliciously. The result is both soft and crisp, spicy and sour, turning something that could have been wasted fish into a sweet, tangy, crunchy delight.
500g fish fillets (black bream, sea bass, red gurnard, pouting and pollack are ideal)
Juice of 3 limes
Juice of 2 lemons
Juice of 1 orange
1 red chilli, deseeded and chopped
1 clove garlic, peeled and crushed
1 tsp caster sugar
1 red onion, peeled and sliced
2 inner stems of celery, sliced
Salt and freshly ground black pepper
Trim your fish fillets carefully. You need completely ‘clean' fillets, without bones, skin, scales or membranes. Slice the fillets into pieces, about 2 inches long and at least ½ inch thick. If the pieces are too thin, they'll ‘overcook' and turn mushy. Pour the lime juice over the fish and toss lightly. Limes have more acid than other citrus fruits, so adding this first kick-starts the ‘cooking' process. Refrigerate or keep in a cool box while you prepare the rest of the marinade.
In a bowl, mix the lemon and orange juices with the chilli, garlic, sugar, a good pinch of salt and lots of pepper. Taste the marinade and tweak the flavours to your liking: it should be citrus-sharp, but also fragrant and with a hint of sweetness. Once you're happy, pour the marinade over the fish chunks. Add the onion and celery and mix it all together. Leave in the fridge for a minimum of 15 minutes to ‘cook'. I personally wouldn't leave it longer than an hour, but you can leave it overnight if you choose.
Serve in little bowls, making sure that each has a generous portion of the marinade along with the fish and vegetables. Toasted crusty bread is a great accompaniment.
Olive or rapeseed oil, for frying
12 fillets of mackerel or scad mackerel, garfish or herring
For the marinade
100ml cider or balsamic vinegar
200ml apple juice
1 hot red chilli, finely chopped
2 shallots or garlic cloves, peeled and chopped
A couple of bay leaves
Grated zest of 1 lemon
Salt and freshly ground black pepper
Heat a thin layer of oil in a non-stick frying pan over a medium-high heat. Fry the fish fillets, in batches, for a couple of minutes each side, until lightly coloured and just cooked. Transfer to a large dish in which they will fit snugly in one layer.
Combine the vinegar and apple juice and add to the frying pan with the chilli, shallots, bay leaves and lemon zest. Heat until simmering, then cook for a couple of minutes, scraping up any crispy bits from the pan as you do so. Season well with salt and pepper. Pour this hot marinade over the warm fish fillets in their dish, to cover them completely.
Leave to cool, then chill for a few hours - or up to 24 hours - before bringing back to room temperature. Serve with lots of bread for mopping up the marinade.
This is an edited extract from Sea Fishing by Nick Fisher (£14.99, Bloomsbury)
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