has a wider meaning than merely putting things like jam or pickles into pots: it also denotes a method of preserving meat or fish in a pot sealed by a layer of fat to exclude air. (Potted cheese is considered separately, see above.)
Potting is an old technique derived from that of the medieval pie, which was often used deliberately as a way of conserving food rather than merely presenting it. The crust of the most solid raised pies was made from coarse flour. It was not intended to be eaten, except as a remnant thrown to the servants, but constituted a durable and airtight shell. The food inside it kept for quite a long time because, having been cooked in a sealed container, it was sterile. The explanation was not understood in the Middle Ages, but the effect was obvious in practice. Observation must also have shown that the weak point where decay began was the top of the filling which did not intimately touch the top crust, because the filling shrank in cooking; and which was exposed to the entry of air through places in the crust where steam had escaped. Therefore the top of the filling was sealed by pouring in, through a hole in the crust, boiling stock or melted fat, which luckily had themselves been sterilized by heating. When this addition solidified it sealed the filling effectively. Such pies were used, for example, for sending Severn lampreys from Gloucester to London, a journey of several days which could scarcely have been undertaken with any other of the primitive preservation techniques of the time.
Towards the end of the 16th century it was realized that the crust could be replaced with a pot which was reusable, so that there was no waste of flour. The meat or fish thus potted was sealed with a layer of melted butter. Sometimes a bladder or a piece of parchment was bound over the top of the pot, which sealed the butter from the air and thus kept it from turning.
During the 16th and 17th centuries potting was widely used both as a method of preserving foods at home and to protect it in transit. The lampreys which had once been sent to London in a pie now went in pots. Other delicacies were also dispatched to the capital in this way, such as small birds. Brawn, which in the Middle Ages had been a pottage and had later become a pickle of fatty pork with verjuice and wine, now became a potted dish. Potted meat or fish might be in large or small pieces, or pounded to a paste. Such foods were a fashionable item at the dinners of the rich, and a useful standby for anyone: one could broach a pot of pigeon (a popular variety) as easily as a modern cook would open a can. Potted foods were usually eaten cold. Estimates of keeping time ranged from a month to a year or more.
The French equivalents of the English potted foods have various names. Confit was and is made mainly in the south-west. Rillettes are a speciality of the Loire region. A terrine is really a potted food, although seldom made for long keeping and therefore with only a thin layer of fat on top. (These are often called pâtés: technically a terrine is anything made in the earthenware dish of that name, usually rectangular with a lid, and a pâté is enclosed in pastry (pâte). This distinction applies whether the mixture is coarse or fine and whatever it is made of: meat, game, fish, or other things. However, use of the term pâté has been irreversibly widened to include virtually any preparation resembling what is found inside the pastry case of a true pâté.)
Despite their popular success, potted foods had a potential weakness which the older pies and true pâtés did not. A food baked in a crust is sterile, and therefore keeps well. So is a food baked in a pot, provided that it is promptly sealed with adequately hot fat. Many potted foods were so baked: for example, Sir Kenelm Digby's recipe (1669) for potted pigeons involved baking them for eight or ten hours in claret and butter, followed by more butter as a seal. He confidently asserted that it would keep for ‘a quarter of a year’, and this seems reasonable. However, no need was felt to bake the food in the pot, and often recipes made it impossible to do so. The food might be cooked in a liquid which was drained off and replaced by butter for potting; or it might have to be pounded after cooking but before it was put in the pot. Since there was no notion at the time of the need for sterility in preserving, no one realized that this would let in bacteria and that the potted food would go bad, as it often did. Hannah Glasse has a direction in her Art of Cookery (1747) ‘to save potted birds, that begin to be bad’. They were put into boiling water for half a minute only, then dried, seasoned with salt, pepper, and mace, and repotted.
This would not have worked. By the time it was realized in the 19th century—first practically by Appert, then scientifically by Pasteur (see canning)—how food becomes contaminated, the vogue for potted foods was waning. The role that potting played in preservation has been taken over by canning or made unnecessary by refrigeration and improved transport. Those potted foods that are still made survive because they are delicacies: for example, potted shrimps in England, or French terrines or rillettes.
Humbler survivals are the British commercially made meat and fish pastes sold in jars for spreading on bread. During the heyday of potting other foods were treated in the same way. Potted cheese has been mentioned; this did not need to be sealed, as it was preserved naturally by the protective bacteria of the cheese. Attempts were made to pot fruits and vegetables. Although these seldom worked, they were stages on the way to the discovery of canning.
Potting has always been principally a European method of preservation. A couple of exceptions are mentioned under confit. The Chinese have been preserving meat and fish in pots since several thousand years bc, but always by making it into a fermented pickle so that it protects itself without the need for sealing.
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.
Digby, Sir Kenelm (1669), The Closet of Sir Kenelm Digby Knight Opened, ed Anne MacDonnell, London: Philip Lee Warner (1910); ed Jane Stevenson and Peter Davidson, Totnes: Prospect Books (1997).
