helps to preserve them and also gives an attractive flavour. In the past it was important as an adjunct to salting and drying in the preservation of fish and meat; but even then it was used for other foods where it was not necessary to preserve them. Now that techniques of preservation have advanced, smoking remains in use for flavouring.
Wood smoke contains tarry substances which are deposited on the food, and whose flavour penetrates it to some extent. These substances contribute to preservation by killing bacteria. They form an impervious layer on the surface of the food, sealing it from the air. This averts rancidity of fat caused by exposure to the air; so smoking is especially useful for fatty foods such as herring or bacon. Smoking also helps preservation through the heat of the process, which dries the food. However, smoking is not generally used on its own as the only preservation method for a food, since it has a limited effect.
Cheese, fruits, and even nuts and hard-boiled eggs are smoked, but the method is associated particularly with fish and meat, and was probably first used for these. It is practised in many regions of the world, perhaps originating independently in several of them in prehistoric times. The discovery would have come when a fire was lit under fish or meat which was being dried, either to speed up drying or to keep away flies. The pleasant flavour and improved keeping quality would have been noticeable as an effect of the smoke. As early as 3500 bc the Sumerian civilization of Mesopotamia was smoking fish; and the Chinese may well have been practising it equally early, though there is no evidence of this until later, when smoked foods are mentioned as normal items. An unusual delicacy of China in the T'ang dynasty (ad 618–907) was black smoked apricots, made in Hubei province.
The simplest method of smoking food, by hanging it over an open wood fire, is effective, but better results can be achieved by using an enclosure to concentrate the smoke. A mud kiln with a small hole in the top to let the smoke out slowly, another at the side for maintenance of the fire, and a few sticks across the inside for suspending the food works well. In modern Africa large oil drums are often adapted for the purpose.
The Romans had smoked cheese, both locally made and imported. The modern cheese caciocavallo, originally made in pairs tied together for hanging up and smoking, is of very ancient origin and may be a descendant of a Roman type.
Smoking fish in Europe goes a long way back. The remains of what seems to be a fish drying and smoking station have been discovered by the River Bann in Ireland. They are dated to about 2000 bc, almost 1,500 years before salting was introduced into W. Europe.
In classical times the fish of the Mediterranean and Black Sea were often preserved by smoking, and the Greeks were adept at the art. The Romans paid large sums for special products such as salsamentum, smoked Black Sea tuna packed in jars. Tuna are oily fish for which, as noted above, smoking is especially suitable.
In medieval Europe smoked herrings were a common food, as important as dried white fish in the diet of the poor. An English document of 1349 mentions specially built smokehouses for herrings, showing that the business was carried on on a large scale. A smokehouse was simply a high, narrow building crossed by small beams between which sticks were laid from which the fish were hung. The roof was covered with tiles which were not cemented, and the smoke escaped through the gaps between them. The fire at the bottom was of oak if possible, ash being a second choice. The whole process took several days, with intermissions to allow the fish to ‘rest’. Such smokehouses continued to be built with little alteration until recently: the first continuous kiln, with the fish carried through on chains, was not patented until 1883. In fishing districts fishermen's wives smoked their own fish in the chimney. This practice was very common in Scotland until the mid-19th century: the use of peat as a fuel made the process easy and successful.
Haddock, not an oily fish, was often smoked. Salmon, from early times and until the 19th century a common fish, especially in Scotland, was also smoked. Again, this was a salty, hard product, not like modern smoked salmon, which has a tender and slightly moist texture and in most instances a mild flavour (which will, however, be influenced by the kind of wood burned to produce the smoke, and can sometimes be strong). There is a marked difference today between a lighter London cure and the Scottish cure.
The practice in English smokehouses was to treat fish at a reasonably low temperature, not normally above 29 °C (85 °F); this is termed cold-smoking.
In N. Europe a different process was developed in the Hanseatic ports: hot-smoking, in which the smoke temperature may be well above boiling point and the fish is wholly or partly cooked. Herring treated by such a method are known as Bücklinge, Anglicized to ‘buckling’. The same process has also been used for other fish, such as mackerel, eels, salmon, and sturgeon.
Hot-smoking does not prolong the keeping time of the fish; it is used for its effect on the flavour and texture only. The combination of smoking and cooking is found in the Orient and elsewhere. For example, the Japanese cook mackerel, bonito, and tuna by steaming them before smoking, after which they are dried.
In Africa hot-smoking of fish is common. In Ghana a kind of shad called bonga is smoked and cooked (indeed, often burnt black) in simple kilns made from oil drums.
Smoking is also used for many kinds of preserved meat. The primitive dried meat strips of the charqui (see jerky) or biltong type, which have been prepared by hunters since prehistoric times, would often have been hung over a fire to make them dry more quickly. In medieval Europe bacon and ham were always smoked as part of the preservation process needed to make them last through the winter. Unsmoked gammon (see bacon) preserved only by brining has a relatively short keeping time. As in any smoking process, the benefits were drying, coating, and flavouring; but the coating was often taken a step further. The peculiar black hams which are still made in several European countries are smoked over a fire of coniferous wood which gives them this thick, tarry coating. The purpose is to make them flyproof; another result is a strangely resinous flavour.
Pork was not the only meat that was smoked, and preserved meats similar to ham or bacon have been prepared from beef, mutton (especially popular in Iceland), goat, and wild boar. Turkey and duck are also smoked, as are some kinds of sausage, for example frankfurter.
During the 19th century improvements in transport, notably the building of railways, allowed less drastic methods of preservation to be used. When the use of refrigeration became general, the tendency was reinforced. Smoked fish was one of the first types of food to benefit from this. Around 1835 a new type of lightly salted, lightly smoked bloater (see herring) was first made at Yarmouth.
In 1843 or shortly before, John Woodger of Northumberland invented a new kind of smoked herring which he called the ‘Newcastle kipper’, a name deliberately taken from the older ‘kippered salmon’. Thus was born the famous British kipper, prepared by splitting and gutting, lightly salting, and smoking them overnight. In the next few decades these kippers almost completely took over the market from the old salty red herrings. At the same time the Scottish smoking of haddock became lighter, to produce the ‘Finnan haddie’, a golden-yellow split fish. (For this and similar products see haddock.)
In continental Europe the trend towards lighter smoking, noticeable in the treatment of buckling (mentioned above), was slower to affect bacon and ham, which were often stored for a long time and needed greater protection. Now, however, ‘smoked’ bacon is barely smoked at all, and needs to be refrigerated.
The choice of wood for smoking has an important influence on the flavour. Hardwoods are best. Oak is preferred in Britain, hickory in the USA. Beech and birch are also good. Softwoods give a resinous, bitter taste which is generally unwanted. However, a small proportion may be added to give a dark colour. A small amount of an aromatic wood, for example apple, rosemary, or juniper, may be added toward the end of smoking for a special flavour.
Wood smoke contains some carcinogenic substances, and frequent consumption of heavily smoked food is thought to be a health risk. However, the trend in the 20th century has been towards lighter smoking.
Alan Davidson was a distinguished author and publisher, and one of the world's best-known writers on fish and fish cookery. In 1975 he retired early from the diplomatic service—after serving in, among other places, Washington, Egypt, Tunisia, and Laos, where he was British Ambassador—to pursue a fruitful second career as a food historian and food writer extraordinaire. Among his popular books are Seafood of South-East Asia, North Atlantic Seafood, and Mediterranean Seafood. In 2003, shortly before his death, he was awarded the Erasmus Prize for his contribution to European culture.
