Cured fish is, for me, the highlight of the Finnish Christmas table. Along with the ubiquitous gravad lax, we also prepare gravad sea bass, which turns out rather similar results to a fish known as siika, which is not available here. Curing and smoking is a strong part of Finnish culinary traditions, and they produce a wide range of delicious products. Being a bit fed up with the less flavoursome smoked salmon more commonly available here, I have been cold smoking at home for some years, with great results, and it is easier than one might imagine.
It is important to appreciate that these cured products are not cooked. The salt in the cure draws out the moisture from the flesh, making it difficult for the bacteria that would otherwise cause spoilage to proliferate. I have been curing fish for more than 20 years now, and have made gravad lax in great quantities. I first learnt about curing from mother-in-law Riitta, who has been making these dishes for much longer. In that time, we have never had any problem from cured fish, nor is it, in my opinion, likely. Nonetheless, one must be careful: use only the freshest fish; ensure prepared fish is kept at appropriate temperatures; maintain strict hygiene, cleaning all surfaces with anti-bacterial cleanser; and ensure that all boards, knives, etc., are properly cleaned. One potential threat that it is well worth being aware of comes from botulinum, the toxic by-product of which is very dangerous. Whereas salting deals with much bacterial growth, it does not prevent the proliferation of botulinum, spores of which are present in the environment. Nitrates are often added to cured products, especially smoked products and meats, to prevent botulism. I do tend to add 1 tsp of so called ‘pink salt’ – also known as Prague powder #2 – for each kilogram of fish, for those intended for cold smoking. Nitrates have their own health concerns, and one must be especially careful to use the correct quantities, as they are harmful in large doses.
We have never had any problem with our home cured fish, but it is best to be aware of potential issues with uncooked products. The bottom line is this: if you are not entirely comfortable with curing and food preservation issues, it is best left well alone. I have included my cures, below, but I am not an expert. Satisfy yourself that these cures are appropriate before using.
We use a coarse sea salt for our cures, because I am fond of the flavour. One might also use a fine ground salt, in which case it may be appropriate to reduce the amount used. Riitta and I always have the same debate about the sugar – I favour brown sugar, as I like the slightly more rich and nutty taste, whilst Riitta always wants to use white sugar. Either is fine, though, so we compromise and prepare the gravad lax and sea bass with white sugar and the smoked fish with brown.
The process is essentially the same for all of these dishes. Fillet and carefully pin bone the fish. One can buy a pair of tweezers specifically intended for this purpose, but a pair of clean pliers is just as good and I have for many years left a pair of bent nosed pliers just for kitchen use. Weigh the fillets and calculate the correct amount of cure. Mix the salt and sugar in a bowl. Lay out an appropriately sized sheet of thick foil and sprinkle a little of the cure where the fish will sit. Lay one fillet on the cure, skin side down. If curing more than one fillet, they are ideally placed on top of each other, flesh side together, and turned once during the curing process. Sprinkle any flavourings on the fillets then rub in the rest of the cure. If using dill, or other herb, finely chop the leaves and sprinkle on top of the fillets, placing the stalks under the skin side. Wrap the fillets tightly in foil. I like to wrap in a second sheet and seal well to prevent the brine that forms from escaping. Place in the refrigerator for the prescribed time. Although one can weigh down the fillets, I have not generally found this to be necessary.
To prepare the fish, remove from the foil package and wipe down. Those intended for smoking can be rinsed and patted dry, and placed uncovered in the refrigerator for several hours. During this time the surface will dry a little, and the pellicle will form, to which the smoke will adhere. Those intended for eating straight away can be rinsed, if need be, or just wiped down.
For cold smoking we currently use an old refrigerator. A metal container holds the wood chips, which we get smouldering with a soldering iron. A three metre length of aluminium ducting takes the smoke into a hole cut into the side of the refrigerator, where it accumulates and vents through another, small, hole in the top. The length of ducting allows the smoke to cool before it reaches the fish. In the middle of the pipe is a small fan, such as used in cooling PC processors. I connect this to a variable power supply. The fan, set at the right speed, keeps a stable smoulder and gets the smoke moving. One can, of course, buy suitable equipment for cold smoking, or follow one of the various plans that one can find online. Our arrangement works well enough, but I do plan, eventually, to build a rather better facility for both hot and cold smoking.
I use alder wood for smoking, as is traditional in Finland. The smoke flavour is rich and rounded, but without the harshness that often comes with smoked products. The results are markedly different in flavour from those smoked, for example, over oak. The smoke produced by my method is dense and after three to four hours the fish has taken on a strong smoked flavour. Once smoked, I wrap the fish in baking parchment and leave overnight, during which time the flavour mellows.
As well as cold smoking, we also prepare hot smoked trout – small, whole trout, which we prepare in a Finnish smoking box – a box with a sliding lid, in which one places some woodchips, then a drip tray, and then one or two grills to hold the fish. This is placed on the barbeque to smoke for 30 to 40 minutes. For this meal, we allow the fish to cool, but they are also excellent eaten hot. Although one can cure the fish for hot smoking, we do not, smoking small fish whole in their skins, which protects them from the harsh elements of the smoke, and ensures that the flesh remains moist. All we do is season the cavity with a little salt.
Quantities of cure in the following recipes are per kilogram of fish.