The Catch Salt, heat and smoke
Smoking is one of the oldest methods of preserving perishable foodstuffs, including fish.
It probably arose out of the practice of drying food. Meat and fish can be preserved by drying in the air or over a slow fire. Air-dried fish remains popular with many ethnic groups, primarily those living in high latitudes.
In New Zealand, Maori preserved fish in huge quantities, usually by air-drying on racks exposed to the wind. Dried kahawai, sharks, barracouta and eels were staple foods, but most fish could be dried and the technique was also used to preserve the meat of sea mammals. Dried fish was a valuable commodity – coastal iwi traded it with inland people for handicrafts and forest goods.
While air-drying works well, the end result can be quite variable depending on weather conditions. Air-drying preserves food by dehydrating it, but too much humidity in the air can result in the food retaining too much water and spoiling before it properly dries. Dry air is a prerequisite for success.
Drying food works as well in cold climates as it does in hot ones, provided humidity is low. Meat and fish have been dried for thousands of years in cold areas where the air is also very dry – high latitudes and mountainous regions – as well as in areas with hot, dry climates. Cod has been air-dried in Spain and Portugal for centuries and Southern Africa is famous for its dried meat (biltong).
The alternative to air-drying food is drying it over a slow fire. Traditionally in Europe this was achieved by hanging meat or fish in the chimney – think bacon and ham. This method is more controllable and works everywhere, including in humid tropical regions. Most cultures are familiar with this style of food preservation.
Suspending food over a slow fire not only drives out moisture, it also subjects it to the effects of heat and smoke, which is why fire-dried/smoked meat and fish looks, feels and tastes different to air-dried products like bacalao (dried cod).
People clearly enjoy the flavour smoke imparts to food, which also undergoes other changes during the smoking process. It was quickly discovered that fish or meat treated with salt (which removes moisture) and then smoked didn’t need to be dried to the same extent to preserve it.
Perhaps only the Scandinavians love smoked fish more than Kiwis. We eat lots of it and smoking fish (and other foods) at home is a popular pastime. Although perhaps less common than it used to be given our now more urban lifestyle, a purpose-built smoker, or a garden shed, an old fridge, or a discarded stove converted into a smoker, is still a feature of many Kiwi backyards.
Various high-tech electric smokers are even more common, alongside BBQS that also smoke food and the ubiquitous methsfired hot-smoking boxes sold cheaply by outdoors and marine outlets everywhere.
HOT OR COLD
The smoking process can be conveniently divided into two: ‘hot’ smoking, where the food is heated enough to cook completely and ‘cold’ smoking, where the heat is kept low enough that the food doesn’t cook in a conventional sense. Hot smoking is a quick process while cold smoking may take days or weeks.
Fish is usually ‘brined’ – soaked in salty liquid – overnight or longer before being wiped dry and smoked. The application of salt ‘cures’ the food and the salty brine needs to fully penetrate to preserve it, so the brining stage is vitally important for coldsmoked products.
Whether hot or cold smoking, the ‘cook’ usually adds flavours that will accentuate or complement the flavour of the smoke. Hot smoking is generally less involved, the cook rubbing the food with a good quantity of salt, usually mixed with sugar, herbs and other flavourings so the surface of the smoked food caramelises. You can use brine, but a dry salt rub does a pretty good job.
Done properly, cold smoking raises the internal temperature of the food to 30° C, but not much higher. A good smoker maintains a uniform temperature throughout the smoking process, maintaining the food’s internal temperature at the magic 30°C. Smoking can last a few hours or as long as 30 days,
Perhaps only the Scandinavians love smoked fish more than Kiwis.
but fish is usually smoked for a shorter time than meat.
Hot-smoking cooks the food, raising the internal temperature to over 100°C, so ultimately curing is less important. Hot-smoked fish keeps well in the fridge – longer than fresh or cooked fish – but nowhere near as long as coldsmoked fish.
Additional flavours may be added to the brine or salt rub, or during the smoking procedure, and the flavour of the smoke can be altered too, by burning different woods and adding flavours to them.
Commercial smokehouses generally employ the cold smoking method, using their own special brine recipe, custom flavourings and smoke regimes which may differ considerably between smokers. In New Zealand, manuka/ kanuka wood is favoured by many commercial and recreational smokers for its distinctive taste and smell, but the wood, wood shavings, wood chips and sawdust of many different trees can be used to make smoke.
Various fruit woods like apple or cherry impart a slightly sweet flavour, while hardwoods like pohutukawa, oak and maple provide more robust flavours. Cedar wood smoke has a strong taste that makes it especially suitable for smoking oily fish like salmon. Avoid soft, sappy woods like pine, which contain too much tar and other toxins, and never use treated timbers or sawdust.
Packaged wood chips and sawdust intended for smoking meat and fish is readily available from outdoors, marine and BBQ outlets.
Some commercial smokehouses service food retail outlets exclusively, but most also offer smoking services to individuals. Many coastal towns and villages have a resident ‘smokie’ who can smoke all or part of your catch, including large fish such as marlin and swordfish. These businesses are well worth seeking out.
Vacuum-packed cold-smoked fish will keep for a couple of weeks in the fridge and months or even years when frozen, but no more than a day or two unrefrigerated. Salmon keeps less well than some other fish.