Consider the Fork

by Bee Wilson

  It was one thing to convince his friends and acquaintances, still another to convince the general public. Rumford’s idea was ahead of its time. His ingeniously designed stoves never found a wide audience (though various sellers would later market and sell “Rumford stoves” that had no connection with the original). Rumford’s invention was not helped by the fact that it was largely made from bricks, containing very little iron. This meant that ironmongers—who at this time were the main manufacturers of cooking apparatus—had little incentive to reproduce the design.

  There was also the fact that smoky and wasteful as they might be, cooks clung to their open fires as simply the only way to roast meat. Campaigners for smokeless stoves in the developing world face the same obstacles today The average Third World open cooking fire—fueled by coal, dung, or wood—generates as much carbon dioxide as a car. Around 3 billion people—half the world’s population—cook like this, with dreadful consequences, both for carbon emissions and individual health: such fires can cause bronchitis, heart disease, and cancers. The World Health Organization has calculated that indoor smoke, chiefly from cooking fires, kills 1.5 million people every year. Yet when aid workers go into villages in Africa or South America offering clean, nonpolluting cookstoves, they often encounter resistance, as people stubbornly stick to the smoky fires they have cooked on all their lives.

  In 1838, four decades after Rumford’s warnings on the dangers of open hearths, cookery writer Mary Randolph insisted that “no meat can be well roasted except on a spit turned by a jack, and before a clear, steady fire—other methods are no better than baking.” There continued to be innovations in jack design, long after you might have expected to see the last of them. In 1845, a Mr. Norton took out a patent for a spit propelled electrically with the aid of two magnets, a strange clash of old and new technology. Over Victoria’s century, Britain entered the age of gas lighting, high-speed rail travel, flushing toilets, and telephones; and still many people chose to have their meat cooked before a roaring fire. As late as 1907, the Skinners Company in London had an eleven-foot-wide roasting range installed in their Guild Hall kitchen.

  The prejudice against closed-off cooking ranges was largely that they seemed too much like bread ovens. Only open fires could roast, it was believed. Ovens were things that baked. In European kitchens, the two kinds of heat were stubbornly kept apart.

  In the East, this division has not existed to anything like the same extent. The Arabic word for bread is khubz, which generates the verb khabaza, meaning to bake or “to make khubz.” But khabaza can also mean to grill or to roast. This single verb thus brings together what in English would be three separate cooking techniques. All three techniques can be performed in a tannur, or clay oven.

  Basic clay bread ovens go back at least as far as 3000 BC in the Indus Valley and Mesopotamia, on the site of modern-day Iraq and Pakistan. These bread ovens had the traditional round cylindrical clay form that they still have to this day in much of rural Africa. A fire is lit in the bottom of the cylinder, and dough is lowered in through a hole in the top and slapped on the side of the oven; it is lifted out again a couple of minutes later as flatbread. These clay ovens look like upside-down flower pots. In Iraq, the name for these ovens was tinaru. We would call them tannurs or tandoors, a technology still in use throughout the Middle East, Central Asia, and Southeast Asia.

  Although it has been refined over the past 5,000 years, the tannur/ tandoor serves the same purpose it always has: a provider of intense, dry baking heat. The tannur enabled households, even humble ones, to be self-sufficient in bread. A series of laborers’ houses have been excavated in an ancient Egyptian village, Amarna, dating to 1350 BC. Half the houses, including small ones, show traces of cylindrical clay ovens. Whereas in Europe there was a persistent belief that the only true bread was that baked by professional bakers, in medieval Iraq, homemade tannur bread was preferred. A market inspector in medieval Baghdad noted that “most people avoid eating bread baked in the market.”

  The tannur offered different cooking possibilities in the home than fire alone. Despite being cheap and portable, these clay ovens provided some heat control. An “eye” at the bottom could be opened or shut to increase or reduce the temperature. For some breads—such as a round Iraqi “water bread” coated in sesame oil—a more moderate heat was used. But clay ovens could also get furnace-hot when needed. Because the wood or charcoal is burned directly in the bottom of the tandoor and continues to burn as the food cooks, the temperatures in a modern tandoor can be tremendous: as much as 896°F (compared with a maximum temperature of 428°F for most domestic electric ovens). It is this blistering heat that makes this oven such a powerful and versatile piece of equipment.

  The uses of the tannur went far beyond baking, which partly explains why in Middle Eastern and Eastern cookery, the baking-roasting dichotomy did not exist. As well as baking bread, cookies, and crackers, a tannur could be used for stews and casseroles and for roasting meat. Today, the tandoor is probably most famous as a device for cooking chicken marinated in yogurt and red spices: tandoori chicken. In tenth-century Baghdad, the tannur was used to roast such things as “fatty whole lamb or kid—mostly stuffed . . . big chunks of meat, plump poultry and fish.” They were placed on flat brick tiles arranged on the fire or securely threaded into skewers and lowered into the tannur until they roasted to succulence. There was clearly no sense here that you could not “roast” meat in an oven. However, the heat of a tandoor works on food in a different way than a Western bread oven.

  There are three different forms of cooking heat. All cooking obeys the second law of thermodynamics: heat flows from hotter things to colder things. But this transfer of energy can happen in more than one way. The first way is radiant heat. Imagine the way an Italian frittata omelette suddenly puffs and browns when you put it under the grill. The grill itself hasn’t touched the omelette; and yet it is cooking. This is from heat radiation, like the sun’s rays. Like radio waves, radiation works without any contact: the thing being heated and the heater do not need to touch. A red-hot fire provides lots of radiant heat, from both the flames and the embers. The moment in Ivan Day’s kitchen when he poked the fire and the heat levels jumped up from bearable to unbearable represented a sudden leap in the quantity of radiant heat, enough to produce a sizzling crust on a joint of beef.

  The second type of heat transfer is conduction. Unlike radiation, it works from material to material, via touch. Some materials are very good conductors, notably, metals. Others are poor conductors, such as clay, brick, and wood. When something heats up, its atoms vibrate rapidly. Conduction works by passing on these vibrations from one material to another: from a metal saute pan to a piece of steak; from a metal saucepan handle to a tender human hand.

  The third type of cooking heat is convection. It happens when the molecules in a fluid—whether air or water, stock or oil—diffuse heat to one another. The hot parts of the liquid or gas are less dense than the cold parts: think steam as opposed to water. Gradually, the hot fluid transfers energy to the cool fluid, until all is hot: think of porridge bubbling in a pot or the air in a preheating oven.

  Any given method of cooking will involve a combination of these forms of heat, but one or another usually dominates. What makes the tandoor so unusual is that it combines all three forms of heat transfer in one. There is a massive blast of radiant heat from the fire below, plus more radiation from the heat retained in the clay walls. Bread cooked on the walls or meat cooked on skewers gets hot by conduction from the clay or the metal skewers. Finally, there is some convected heat from the hot air circulating in the oven. The tandoor provides intense and potent heat: the kind you can use to cook almost anything.

  The ovens of Western cooking were generally brick boxes. Heat transfer in this sort of oven is typically around 8o percent by convection and only 20 percent by radiation. In place of the intense constant heat of the tandoor was a heat that started fierce but became progressively cooler. Indeed,
the food didn’t go in until the flames had already gone out. Over centuries, cooking styles evolved to reflect this gradual cooling off, with a repertoire to make the most of every phase of oven heat. Food was cooked in succession: bread went into the hottest oven, followed by stews, pastries, and puddings; later when the oven was barely warm, herbs might be left to dry in it overnight.

  It is true that the West had its own equivalent of the tannur in the “beehive ovens” introduced by the Romans, but these never penetrated the entire food culture as the Eastern clay ovens did. In ancient and medieval Europe, bread ovens tended to be vast communal chambers, feeding an entire community with bread. The baking equipment used in a manorial or monastery kitchen was all on a giant scale: dough was stirred with wooden spoons as big as oars and kneaded on vast trestle tables. Communal baking ovens were stoked up via stoking sheds from outside. First the fuel—bundles of wood or charcoal—was heaved into the back of the oven and fired up. When the oven was hot, the ashes were raked out into the stoking sheds and the dough was shoved in, on great long wooden paddles called peels. Like turnspit boys, bakers worked almost naked because of the heat.

  There the similarity ended. Western baking and roasting were entirely separate activities with separate equipment, methods, and recipes. By the eighteenth century, baking involved a paraphernalia of wooden kneading troughs, pastry jaggers, various hoops and traps for tarts and pies, peels, patty pans, wafer irons, and earthenware dishes. The baker had no need of jacks and spits, gridirons, and fire dogs. There is an engraving of the royal kitchen at St. James’s Palace during the reign of George III, around the time of American independence. It depicts three different types of fire cookery. There is an open grate for roasting, a closed oven for baking, and a raised brick hearth for making stews and sauces. Each operation is entirely distinct.

  No wonder Rumford’s closed range met with such ridicule and derision when it was first introduced. It threatened to bring together two technologies—baking and roasting—that almost everyone in Britain, if not the Western world, deemed to be incompatible. It was as if he had said you could use a deep-fat fryer for steaming or a toaster to boil eggs.

  There were also doubts from many quarters over whether the enclosed heat of an oven could ever replace the homely pleasures of warming yourself by an open fire. Could a stove whose flames were hidden from view ever be a focus in the way that a hearth was? A fire speaks to us in ways that are not always rational. For all the hazards and smoke of a roasting fire, those flames signified home. It was said that when stoves were first introduced in the United States in the 1830s, they inspired feelings of hatred: stoves might be an acceptable way to heat a public place such as a barroom or courthouse, but not a home.

  In time, most people got over their repugnance. The “model cookstove” became one of the great consumer status symbols of the Industrial Age, and homes developed a new focus. The typical Victorian cookstove was a cast-iron “monster” that combined a hot-water tank for boiling and hot plates to set pots and pans on with a coal-fired oven behind iron doors, the whole thing connected with “complicated arrangements of flues, their temperature controlled by a register and dampers.” By the mid-nineteenth century in both Britain and the United States, the closed range or “kitchener” had become the single essential kitchen fitting in middle-class kitchens. Cooks learned that instead of building a kitchen around a fire, it could be built around an appliance, just as today’s affluent kitchens are structured around brightly colored KitchenAids and gleaming Viking ranges.

  At the Great Exhibition in 1851, when Britain showed off its industrial riches to the world, many kitcheners were on display. First prize went to the Improved Leamington Kitchener, an elaborate construction, which Mrs. Beeton admired. The Leamington explicitly offered to combine the twin functions of roasting and baking with a single fire. Inside was a wrought-iron roaster with a dripping pan, but this could be converted to the unventilated heat of an oven by closing the valves at the back. The Leamington could also supply gallons of boiling water. A range was never just designed to cook food; it was needed to provide hot water for the whole household, to heat up irons and warm hands.

  “Leamington” was one of the first pieces of equipment to become a household name in Britain and was soon being used as shorthand for closed ranges in general. But there were plenty of competing models, many of them with patents, glamorous names (“The Coastal Grand Pacific,” “The Plantress”), and fancy squiggles and curlicues on the front. These were cooking appliances as fashion statements.

  The sudden popularity of the closed range went beyond style. It was driven by the materials of the Industrial Revolution, chiefly coal and iron. There was a boom in cookstoves, not because people had read Rumford and turned against open-hearth cookery but because the market was suddenly flooded with cheap cast iron. The patent kitchen range was an ironmonger’s dream: the chance to offload a great lump of iron, with added iron accessories. The rapidity with which new versions came out was an added bonus: after a couple of years, a stove might become outmoded and get traded in for a more up-to-date model, meaning more profits.

  Cast-iron production had improved in the mid-eighteenth century with the discovery of a new method of production, using coal instead of charcoal. John “Iron-Mad” Wilkinson (1728–1808) pioneered the new method and produced the steam engine cylinders that hastened production even further. A generation later, cast iron was everywhere: Victorians shut themselves behind cast-iron gates, rode over cast-iron bridges, sat around cast-iron fireplaces, erected cast-iron buildings, and cooked in cast-iron kitcheners. The housekeepers and their mistresses who pored over the Smith and Wellstood catalog, wondering which model of stove to buy, may have believed that they were satisfying nothing but their own whim. But whichever fancy new design they chose, they were serving the profits of the iron industry and supporting the coal industry as well, as these new modern kitcheners were almost all fired with coal rather than wood or turf or peat.

  Coal was by no means new to the British kitchen. The first coal revolution had taken place in the sixteenth century, when a shortage of wood transformed kitchens. The Elizabethan Age saw a great expansion of industry. Iron, glass, and lead manufacturing were all greedy consumers of timber. Timber was also needed for shipbuilding in the war against the Spanish, leaving far less for English hearths at home. The result was that many kitchens, particularly in towns, reluctantly converted to “seacoal,” so named because it was transported by sea.

  The move from wood to coal brought with it other changes. The medieval wood fire was really an indoor bonfire, with nothing but some andirons (or brand-irons) to stop the burning logs from rolling forward onto the floor. It was a hazardous form of cooking. In the seventh century, the Saxon archbishop Theodore pronounced that “if a woman place her infant by the hearth, and the man put water in the cauldron, and it boil over and the child be scalded to death, the woman must do penance for her negligence but the man is acquitted of blame.” Aside from the injustice of this, it speaks of a world in which children of two or three were at high risk of toddling into hot fires and cauldrons. Women were at risk, too, because of their long, trailing dresses. Medieval coroners’ reports listing accidental deaths indicate that women were more likely to die accidentally in the home than anywhere else. Little girls died at open hearths playing with pots and pans, copying their mothers.

  The combination of wood-timbered houses and open hearths made kitchen fires a common occurrence. The most famous kitchen fire in British history was the blaze starting in the small hours of September 2, 1666, at the bakery of Thomas Farriner, Pudding Lane, which set off the Great Fire of London. When the city was rebuilt in brick, the new houses had coal-burning grates.

  One of the effects of a switch to coal was to enclose the fire—at least a little. Coal needs a container, in the form of a metal grate, called a “chamber grate” or “cole baskett.” The switch from down-hearth wood fires to grated coal fires was accompanied by a wh
ole new battery of equipment. The new fires needed cast-iron firebacks to protect the wall from the fierce heat and complex fire cranes to swing pots over the fire and off again. The other great change brought about by coal was the chimney. The great increase in chimneys in Elizabeth’s reign resulted largely from the increased use of coal, because wider flues were needed to carry away the noxious fumes of the coal as it burned. In fact, as Rumford observed, this combination of very wide chimneys and blazing roasting fires was deadly. When Pehr Kalm arrived in London from Sweden in the eighteenth century, he found the “coal-smoke” from cooking “very annoying,” and wondered if it was responsible for the high incidence of lung disease in England. He developed a terrible cough, which only abated when he left the city.

  Not everyone switched to coal. In the countryside and in the northern counties, the norm remained the old down-hearth wood fire. Meanwhile, the poorest families in both city and country muddled by as best they could with whatever fuel was at hand: handfuls of dry heather, twigs gathered from the hedgerows, cattle dung. Not for them the shiny new patent cookstoves.

  It is debatable whether being unable to afford a coal kitchener was a great loss. The closed range in this particular form had many disadvantages and few real benefits over an open fire. Unlike Rumford’s ideal closed hearths built of brick, many early ranges were badly constructed, belching coke fumes. A letter of 1853 to the Expositor called them “poison machines,” drawing attention to the recent deaths of three people from inhaling their fumes. And besides that danger, many of the ranges were inefficient. Promoters of American cookstoves claimed they would save around 50—90 percent of fuel compared with an open hearth, but this did not take into account the heat wasted. A good stove needs to insulate heat as well as conduct it. There was a fundamental problem in using all that highly conductive iron, which absorbed vast amounts of heat and then radiated it back out into the kitchen rather than into the food, leaving the poor cook in a furnacelike atmosphere of heat, ash dust, and soot.