by Bee Wilson
Culinary knives have always been just a step away from weapons. These are tools designed to break, disfigure, and mutilate, even if all you are cutting is a carrot. Unlike lions, we lack the ability to tear meat from a carcass with our bare teeth; so we invented cutting tools to do the job for us. The knife is the oldest tool in the cook’s armory, older than the management of fire by somewhere between I million and 2 million years, depending on which anthropologist you believe. Cutting with some implement or other is the most basic way of processing food. Knives do some of the work that feeble human teeth cannot. The earliest examples of stone cutting tools date back 2.6 million years to Ethiopia, where excavations have found both sharpened rocks and bones with cut-marks on them, indicating that raw meat was being hacked from the bone. Already, there was some sophistication in the knife skills on display. Stone Age humans fashioned numerous different cutting devices to suit their needs: archaeologists have identified simple sharp choppers, scrapers (both heavy duty and light duty), and hammerstones and spheroids for beating food. Even at this early stage, man was not randomly slashing at his food but making careful decisions about which cuts to make with which tools.
Unlike cooking, toolmaking is not an exclusively human activity. Chimpanzees and bonobos (another type of ape) have shown themselves capable of hammering rocks against other rocks to make sharp implements. Chimps can use stones to crack nuts and twigs to scoop fruit from a husk. Apes have also hammered stone flakes, but there is no evidence that they passed down toolmaking skills from one individual to another, as hominids did. Moreover, primates seem to be less sensitive to raw materials used than their human counterparts. Right from the beginning, hominid toolmakers were intensely interested in finding the best rocks for cutting, rather than just the most convenient, and were prepared to travel to get them. Which rock would make the sharpest flake? Stone Age toolmakers experimented with granite and quartz, obsidian and flint. Knife manufacturers still search for the best materials for a sharp blade; the difference is that the art of metallurgy, from the Bronze Age onward, has vastly expanded our options. From bronze to iron; from iron to steel; from steel to carbon steel, high-carbon steel, and stainless steel; and on to fancy titanium and laminates. You can now spend vast sums on a Japanese chef’s knife, handmade by a master cutler from molybdenum-vanadium-enriched steel. Such a knife can perform feats that would have amazed Stone Age man, swooshing through a pumpkin’s hard skin as if it were a soft pear.
In my experience, when you ask chefs what their favorite kitchen gadget is, nine times out of ten, they will say a knife. They say it slightly impatiently, because it’s just so obvious: the foundation of every great meal is accurate cutting. A chef without a knife would be like a hairdresser without scissors. Knife work—more than the application of heat—is simply what chefs do: using a sharp edge to convert ingredients into something you can cook with. Different chefs go for different knives: a curved scimitar; a straight French “blooding” knife, designed for use by horsemeat butchers; a pointy German slicer; a cleaver. I met one chef who said he used a large serrated bread knife for absolutely everything. He liked the fact that he didn’t have to sharpen it. Others favor tiny parers that dissect food with needle-sharp accuracy. Most rely on the classic chef’s knife, either nine-inch or ten-inch, because it’s about the right size to cover most needs: long enough for jointing, small enough for filleting. A good chef steels his or her knives several times in a single shift, drawing the blade swiftly to and fro at a 20° angle, to ensure the knife never loses its bite.
The story of knives and food is not only about cutting tools getting ever sharper and stronger, however. It is also about how we manage the alarming violence of these utensils. Our Stone Age ancestors took the materials at their disposal and—so far as we can surmise—made them as sharp as possible. But as the technology of knife making developed through iron and steel, the sharpest knife became something casually lethal. The primary function of a knife is to cut; but the secondary question has always been how to tame the knife’s cutting power. The Chinese did it by confining their knife work to the kitchen, reducing food to bite-sized pieces with a massive cleaverlike instrument, out of sight. Europeans did it, first, by creating elaborate rules about the use of the knife at the table—the subtext of all table manners is the fear that the man next to you may pull his knife on you—and second, by inventing “table knives” so blunt and feeble that you would struggle to use them to cut people instead of food.
There is a peculiar joy in holding a knife that feels just right for your hand and marveling as it dices an onion, almost without effort on your part. During the knife-skills course, our teacher showed us how to joint a chicken. When separating the legs from the thighs, you look for two little mountain tops; on hitting the right spot, the knife goes through like silk. This only works, however, when the knife is sharp enough to begin with.
Chefs always say that the safest knife is the sharpest one (which is true until you actually have an accident). Among domestic cooks, though, knowledge of how to keep a knife sharp has become a private passion rather than a universal skill. The travelling Victorian knife grinder, who could sharpen a set of knives in a matter of minutes—in exchange for whatever you could pay him, pennies or even a pint of ale—is long gone.2 He has been replaced by eager knife enthusiasts, who grind their knives not as a job or even out of necessity but for the sheer satisfaction of it, swapping tips in online knife forums. Opinion differs as to which sharpening device is best for achieving the perfect edge, whether a Japanese water stone, a traditional whetstone, an Arkansas stone, or a synthetic aluminium oxide stone. (I know of no real knife enthusiast who would favor the electric knife sharpener, which is generally excoriated for aggressively oversharpening, and hence ruining, good knives.)
Whichever tool is chosen, the basic principle is always the same. You sharpen a knife by grinding off some of the metal, starting with a coarse abrasive and moving to a finer one until you have the required sharpness. In addition, you may wish to steel your blade each time you use it, running it along a steel rod a few times to realign the edge. Steeling can keep a sharp knife sharp, but it cannot make a blunt knife sharp in the first place. What does it mean for a knife to be sharp? It is a question of angle. You get a sharp edge when two surfaces—known as bevels—come together at a thin V-shaped angle. If you could take a cross section through a sharp knife, you would see that the typical angle for a Western kitchen knife is around 20°, or one-eighteenth of a circle. European knives are generally double-beveled, that is, sharpened on both sides of the blade, resulting in a total angle of 40°. Every time you use your knife, a little of the edge wears away, and the angle is gradually lost. Sharpeners renew the edge by grinding bits of the metal away from both sides of the V to restore the original angle. With heavy use and excessive grinding, the blade gradually diminishes.
In an ideal universe, a knife would be able to achieve an angle of zero—representing infinite sharpness. But some concessions have to be made to reality. Thin-angled knives cut better—like razors—but if they are too thin, they will be too fragile to withstand the act of chopping, which rather defeats the purpose. Whereas Western kitchen knives sharpen at an angle of around 20°, Japanese ones, which are thinner, can sharpen at around 15°. This is one of the reasons so many chefs prefer Japanese knives.
There is much that the community of knife enthusiasts disagree upon. Is the best knife large? There’s a theory that heavier knives do more of the work for you. Or small? There’s another theory that heavy knives make your muscles ache. Are you better off with a flat edge or a curved one? The enthusiasts also disagree on the best way to test the sharpness of an edge to see if it “bites.” Should you use your thumb—thus flaunting how at-one you are with the metal—or is it better to cut into a random vegetable or a ballpoint pen? There’s a joke about a man who tested his blade using his tongue: sharp blades taste like metal; really sharp blades taste like blood.
What unites knife en
thusiasts is the shared knowledge that having a sharp knife, and mastery of it, is the greatest power you will ever feel in a kitchen.
Shamefully late in my cooking life, I have discovered why most chefs think the knife is the one indispensable tool. You no longer feel anxious around onions or bagels. You look at food and see that you can cut it down to any size you want. Your cooking takes on a new refinement. An accurately chopped onion—tiny dice, with no errant larger chunks—lends a suave luxury to a risotto, because the onion and the grains of rice meld harmoniously A sharp bread knife creates the possibility of elegantly thin toast. Become the boss of a sharp knife, and you are the boss of the whole kitchen.
This shouldn’t really come as a revelation. But proficiency with a knife is now a minority enthusiasm. Even many otherwise accomplished cooks have a rack stocked with dull knives. I know, because I used to be one of them. You can survive perfectly well in the modern kitchen without any survivalist knife skills. When something needs to be really finely chopped or shredded, a food processor will pick up the slack. We are not in the Stone Age (as much as some of the knife enthusiasts would like us to be). Our food system enables us to feed ourselves even when we lack the most rudimentary cutting abilities, never mind the ability to make our own slicing tools. Bread comes pre-sliced, and vegetables can be bought pre-diced. Once, though, effective handling of a knife was a more basic and necessary skill than either reading or writing.
In medieval and Renaissance Europe, you carried your own knife everywhere with you and brought it out at mealtimes when you needed to. Almost everyone had a personal eating knife in a sheath dangling from a belt. The knife at a man’s girdle could equally well be used for chopping food or defending himself against enemies. Your knife was as much a garment—like a wristwatch now—as a tool. A knife was a universal possession, often your most treasured one. Like a wizard’s wand in Harry Potter, the knife was tailored to its owner. Knife handles were made of brass, ivory, rock crystal, glass, and shell; of amber, agate, mother of pearl, or tortoiseshell. They might be carved or engraved with images of babies, apostles, flowers, peasants, feathers, or doves. You would no more eat with another person’s knife than you would brush your teeth today with a stranger’s toothbrush. You wore your knife so habitually that—as with a watch—you might start to regard it as a part of yourself and forget it was there. A sixth-century text (St. Benedict’s Rule) reminded monks to detach their knives from their belts before they went to bed, so they didn’t cut themselves in the night.
There was a serious danger of this because knives then, with their daggerlike shape, really were sharp. They needed to be, because they might be called upon to tackle everything from rubbery cheese to a crusty loaf. Aside from clothes, a knife was the one possession every adult needed. It has been often assumed, wrongly, that knives, as violent objects, were exclusively masculine. But women wore them, too. A painting from 164° by H. H. Kluber depicts a rich Swiss family, preparing to eat a meal of meat, bread, and apples. The daughters of the family have flowers in their hair, and dangling from their red dresses are silvery knives, attached to silken ropes tied around their waists. With a knife this close to your body at all times, you would have been very familiar with its construction.
Sharp knives have a certain anatomy. At the tip of the blade is the point, the spikiest part, good for skewering or piercing. You might use a knife’s point to slash pastry, flick seeds from a lemon half, or spear a boiled potato to check if it is done. The main body of the blade—the lower cutting edge—is known as the belly, or the curve. This is the part of a knife that does most of the work, from shredding greens into a fine tangle to slicing meat thinly. Turn it on its side and you can use it to pulverize garlic to a paste with coarse salt: good-bye, garlic press! The opposite end of the blade from the belly, logically enough, is the spine, the blunt top edge that does no cutting but adds weight and balance. The thick, sharp part of the blade next to the handle is the heel, good for hefty chopping of hard things like nuts and cabbages. The blade then gives way to the tang, the piece of metal hidden inside the handle that joins the knife and its handle together. A tang may be partial—if it only extends partway into the handle—or it may be full. In many high-end Japanese knives now, there is no tang, the whole knife, handle and all, being formed from a single piece of steel. Where the handle meets the blade is called the return. At the bottom of the handle is the butt—the very end of the knife.
When you start to love knives, you come to appreciate everything from the quality of the rivets on the handle to the line of the heel. These are now fairly arcane thrills, but once, they belonged to everyone. A good knife was an object of pride. As you took it from your waist, the familiar handle, worn and polished from use, would ease nicely into your hand as you sliced your bread, speared your meat, or pared your apple. You knew the value of a sharp knife, because without it you would find it so much harder to eat much of what was on the table. And you knew that sharpness meant steel, which by the sixteenth century was already the metal most valued by knife makers.
The first metal knives were made of bronze during the Bronze Age (c. 3000—700 BC). They looked similar to modern knives in that as well as a cutting edge, they had a tang and bolster, onto which a handle could be fitted. But the cutting edge didn’t function well because bronze is a terrible material for blades, too soft to hold a really sharp edge. Proof that bronze does not make good knives is confirmed by the fact that during the Bronze Age, cutting devices continued to be made from stone, which was, in many respects, superior to the newfangled metal.
Iron made better knife metal than bronze. The Iron Age was the first great knife age, when the flint blades that had been in use since the time of the Oldowans finally vanished. As a harder metal, iron could be honed far sharper than bronze. It was a handy metal for forging large, heavy tools. Iron Age smiths made pretty decent axes. For knives, however, iron was not ideal. Although harder than bronze, iron rusts easily, making food taste bad. And iron knives still do not hold the sharpest of edges.
The great step forward was steel, which is still, in one form or other, the material from which almost all sharp knives are made, the exception being the new ceramic knives, which have been described as the biggest innovation in blade material for three millennia. Ceramic knives cut like a dream through soft fish fillets or yielding tomatoes but are far too fragile for heavy chopping. For a blade that is sharp, hard enough, and strong, nothing has yet supplanted steel, which can form and hold a sharp edge better than other metals.
Steel is no more than iron with a tiny proportion of added carbon: around 0.2 percent to 2 percent by weight. But that tiny bit makes all the difference. The carbon in steel is what makes it hard enough to hold a really sharp angle, but not so hard it can’t be sharpened. If too much carbon is added, the steel will be brittle and snap under pressure. For most food cutting, 0.75 percent carbon is right: this creates a “sheer steel” capable of being forged into chopping knives with a tough, sharp edge, easy to sharpen, without being easily breakable; the kind of knife that could cut almost anything.
By the eighteenth century, methods of making carbon steel had industrialized, and this marvelous substance was being used to make a range of increasingly specialized tools. The cutlery trade was no longer about making a daggerlike personal possession for a single individual. It was about making a range of knives for highly specific uses: filleting knives, paring knives, pastry knives, all from steel.
These specialized knives were both cause and consequence of European ways of dining. It has often been observed that the French haute cuisine that dominated wealthy European tastes from the eighteenth century on was a cuisine of sauces: bechamel, velouté, espagnole, allemande (the four mother sauces of Carême, later revised as the five mother sauces of Escoffier, who ditched the allemande and added hollandaise and tomato sauce). True, but it was no less a cuisine of specialist knives and precision cutting. The French were not the first to use particular knives for partic
ular tasks. As with much of French cuisine, their multitude of knives can be traced to Italy in the sixteenth century. In 1570, Bartolomeo Scappi, Italian cook to the pope, had myriad kitchen weapons at his disposal: scimitars for dismembering, thick-bladed knives for battering, blunt-ended pasta knives, and cake knives, which were long, thin scrapers. Yet Scappi laid down no exact code about how to use these blades. “Then beat it with knives,” Scappi will say, or “cut into slices.” Again, he does not formally catalog different cutting techniques. It was the French, who, with their passion for Cartesian exactness, made knife work into a system, a rule book, and a religion. The cutlery firm Sabatier first produced carbon steel knives in the town of Thiers in the early 1800s—around the time that gastronomy as a concept was invented, through the writings of Grimod de la Reyniere and Joseph Berchoux and the cooking of Carême. The knives and the cuisine went hand in hand. Wherever French chefs traveled, they brought with them a series of strict cuts—mince, chiffonade, julienne—and the knives with which to make them.
French food, no matter how simple, has meticulous knife work behind it. A platter of raw oysters on the half shell at a Parisian restaurant doesn’t look like cooking at all, but what makes it a pleasure to eat, apart from freshness, is that someone has skillfully opened each mollusk with an oyster shucker, sliding the knife upward to cut the adductor muscle that holds the shell closed without smashing off any sharp pieces. As for the shallot vinegar with which the oysters are served, someone has had to work like crazy, cutting the shallot into brunoise: tiny 0.25 cm cubes. It is only this prepping that prevents the shallot from being too overwhelming against the bland, saline oysters.
The savory French steak that sits before you so invitingly—whether onglet, pave, or entrecote—is the result of French butchery using particular utensils: a massive cleaver for the most brutal bone-hacking work, a delicate butcher’s knife for seaming out the more elusive cuts, and perhaps a cutlet basher (batte à côtelettes) to flatten the meat a little before it is cooked. The classical French kitchen includes ham knives and cheese knives, knives for julienning, and beak-shaped knives for dealing with chestnuts.
