A Wooden Knife Sharper Than Steel? Scientists Say So.
Knives are humanity’s oldest tool, dating back millions of years. A group of scientists in Maryland have produced a version made of hardened wood, which they say is sharper than steel.
Knives are the oldest type of manufactured tool, and they’re still evolving. Credit...Karsten Moran for The New York Times
By Derrick Bryson Taylor
Published April 11, 2022Updated April 13, 2022
More than 60 years ago in “Mastering the Art of French Cooking,” Julia Child, one of America’s most emulated chefs, described the necessity of decent, reliable kitchen equipment.
“Theoretically a good cook should be able to perform under any circumstances, but cooking is much easier, pleasanter, and more efficient if you have the right tools,”
Ms. Child said. Among the essentials she named were a heavy-duty electric mixer, a skillet and a knife — specifically, a quality, stainless steel knife that’s “sharp as a razor.”
What Ms. Child could not anticipate was that decades later, researchers in science labs would disagree. Last year, a group of researchers announced they had
developed wood that they say is 23 times harder than its natural counterpart. They used the hardened wood to make a table knife that their study shows is nearly three times sharper than commercial table knives, like those made from steel, plastic and natural wood.
To create the hardened wood, researchers used a process involving a chemical treatment, water rinsing, and both cold and hot presses on basswood. They then soaked it in food-grade mineral oil to increase its water resistance and carved the material into knives.
Basswood, a soft wood
commonly used for woodworking and constructing the bodies of musical instruments, was selected for its high performance after processing, said Teng Li, a professor in the Department of Mechanical Engineering at the University of Maryland, College Park, and the lead researcher on the project.
But the manufacturing strategy used in the study is applicable to other types of wood, too, he said.
Researchers tested the knife by cutting a steak, along with cucumbers, carrots, onions and tomatoes. Although they worked relatively well for researchers in the lab, could a wood knife really replace a traditional one in the real world?
Bob Kramer, a master bladesmith in Bellingham, Wash., said he wanted to see more data, and try using the knife, before forming an opinion. “I say get the thing in front of you, try to cut a lemon, try to cut an onion with it,” he said. “Cut up a raw chicken and see how that goes.”
Having kitchen tools that work well is a “pleasurable thing,” said Mr. Kramer, who has made knives for 30 years. “When it works, you feel the power of it.”
Knives: a brief history
While the future of knives could be taking shape in a lab, historically, they have always changed with the times.
Knives are the oldest known manufactured objects. At least two and a half million years ago, prehistoric humans butchered animals with small stones that were sharpened by striking one stone with another, according to “The Cooks’ Catalogue,” an encyclopedia of cookware published in 1975 and edited by
the chef James Beard and others.
The knife took on different shapes and materials in the Iron and Middle Ages, and around 1600, the table knife was invented. Even though knives gained popularity at the dinner table, they were still used as weapons, drawing fears of danger while dining,
according to the California Academy of Sciences. In order to reduce violence, in 1669 King Louis XIV of France declared all pointed knives — both for the street and table — illegal and ordered them ground down.
Primitive handaxes like these — the one on the left is about a million years old, and the one on the right is about 350,000 years old — were used as cutting tools long before knives hit the table.Credit...The Natural History Museum/Alamy Stock Photo
While knife production soared across Europe in the late 18th century, it has declined and moved to Asia in recent decades, said Alastair Fisher, a director at Taylor’s Eye Witness Limited, a knife manufacturer in Sheffield, England, that has been in business since 1838. Sheffield, a city about 170 miles north of London, played a significant role in producing knives for the English-speaking world, he said. Hundreds of knife manufacturers were once located in Sheffield, he said, and a wide range of knives were produced there. The city’s proximity to multiple natural resources, including iron ore, coal and limestone, made it ideal, he said.
In recent decades, knife production in England has declined, partly because of the growth of fast food and its plastic cutlery, Mr. Fisher said: “Unfortunately people have moved on to having TV dinners.”
But even with the rise of disposable utensils, a niche community of knife enthusiasts is flourishing, and its members have opinions about the idea of a hardened wood knife.
Yao-Fen You, a senior curator at the Cooper Hewitt, Smithsonian Design Museum in New York, said she is picky about her knives. She learned how to use a cleaver around the age of 5 and now owns about 10 kitchen knives, one of them a Miyabi Koh stainless steel knife, costing her about $130.
“I am skeptical,” Ms. You said of a knife made of wood, which contracts and expands. “That tends to be the problem with wood handles. I like the feel of them, but they will deteriorate over time.”
Dr. Li, the University of Maryland professor who helped create the hardened wood, has heard such concerns. Natural wood utensils, like chopsticks, spoons and cutting boards, are widely used in kitchens, he said, and while they do degrade, they can also last a long time. With proper maintenance, he said, he expects hardened wood utensils to last longer than natural wood items. Hardened wood knives can also be resharpened just like steel knives, he said.
Which is better for the environment?
It’s complicated.
Dr. Li argued that the production of metal and alloy-based hard materials is energy intensive and leads to a heavy carbon footprint. However, a typical knife uses less than a pound of stainless steel, according to Chris Pistorius, a co-director at the Center for Iron and Steelmaking Research at Carnegie Mellon University. He said a steel knife’s climate impact was tiny, and its ability to be recycled was a major advantage.
To really assess if a hardened wood knife is better for the environment would require a “life-cycle analysis,” said Jesko von Windheim, a professor at the Nicholas School of the Environment at Duke University. It’s a “cradle-to-grave analysis” that conducts carbon accounting along the way, he said.
Sometimes products appear more environmentally sustainable on the surface but may not actually be, depending on their production process and how they’re disposed of, he said.
“If you want to make the statement that wood knives are better,” Dr. von Windheim said, “you have to do that accounting.”
Steel carving knives in the Taylor’s Eye Witness cutlery catalog, circa 1895.Credit...Taylor’s Eye Witness
Zak Eastop, in Durham, England, said he recently spent about 150 pounds, or $200, on a new kitchen knife. Mr. Eastop described his relationship with the tool as “semi-symbiotic” and said “it feels like an extension of my hand.” He said he worried hardened wood knives wouldn’t last as long as steel and wondered if wood knives could be sharpened. “I can’t imagine replacing high-end steel knives for cooking,” he said. “For dining, yeah, sure.”
Back in Sheffield, Mr. Fisher appeared unconvinced by the researchers and said he thought the knife would struggle cutting wafer-thin slices of smoked salmon.
“I’d love to try one,” he said. “But I don’t think there’s too much panic in Sheffield at the moment.
