Adventures in Printing Food
3-D kitchen printers produce hits (a deep-fried scallop space shuttle) and misses (square milk)
PRINT AND EAT: 3-D printers can do more than make plastic parts. At Cornell University, researchers are changing the shape of food, with geometric chocolates and space-shuttle scallops.
You want to bake a special cake for your mom, so you boot up the 3-D printer in your kitchen. Loaded with a dozen cartridges filled with pastes of chocolate, marzipan, and other ingredients, the machine downloads instructions from the Internet. You key in a specific texture, size, and flavor, and then you insert a 3-D message in the center—Happy Birthday, Mom!—to be revealed only after she takes a bite. The machine does the rest, assembling and baking a pastry so scrumptious it rivals a virtuoso chef’s in richness and complexity. Your mother loves it so much that she insists you send a slice of the same cake—in the form of a digital recipe—to your Uncle Norman’s printer as well. Your 3-D cake recipe gets so many raves, in fact, that you decide to sell the recipe online for 99 cents a download.
Science fiction? Hardly. The technology exists, and over the last eight years people have cooked up all sorts of comestibles with it, some a lot stranger than a cake with printing inside.
Let’s start with the printer. Versions of these machines, which follow an electronic blueprint to create 3-D objects out of layers of different material, have been around for nearly three decades. In the late 1980s, they were van-sized behemoths used in industrial settings for prototyping or for producing small batches of aerospace and medical parts. Today’s consumer models, by contrast, are about the size of a microwave oven and may sell for about US $1000. Between then and now, a whole community of do-it-yourselfers has emerged, eager to exploit the amazing capabilities of these versatile gadgets.
The Fab@Home project began in 2005 to help make the technology accessible to regular folks, and the following year came out with the first open-source DIY 3-D printer. Like most 3-D printers, the Fab@Home system uses a robotic arm with an extrusion head to deposit soft or liquid materials that later harden. While many home 3-D printers use spools of plastic as feedstock, our printer relies on syringelike cartridges that can hold a variety of different pastes and fluids. Researchers have used our machine to print artificial ears from living cells and to build working batteries and actuators from a variety of conductive and nonconductive materials. But what has really fired up the imaginations of DIYers is an application we never foresaw: printing food.
Noy Schaal, a high school student in Louisville, Ky., was one of the first people to use the Fab@Home at home rather than in a research lab. After getting the machine in 2006 she immediately modified it to work with her material of choice: chocolate. Getting the temperature just right took a while, but her printer ended up winning first prize in a local science fair, where Schaal printed chocolate letters, textured bars, and other shapes directly from a computer-aided-design (CAD) model and then handed them to the judges.
Other groups caught on to the printer’s culinary potential, and by the end of that year we at Fab@Home had begun experimenting, too. For starters, we printed hummus and peanut butter in every shape we could render on a CAD system. When the Fab@Home project won the 2007 Popular Mechanics Breakthrough award, the team printed out hors d’oeuvres, made of Brie and apricot comfiture, at the award reception. But our prized creation was—and still is—a space shuttle made from Cheez Whiz. For more than two years, it’s been sitting on a shelf in our lab, unrefrigerated. (Frankly, we’re afraid to eat it now.)
Those early attempts were all made from simple pastes that hardened when dried or cooled. But while a paste-based diet may have sufficed for the early astronauts, it’s too limited for most people. For digital cooking to really catch on, we concluded, the printers needed to accommodate a larger range of recipes, ingredients, and cooking temperatures.
Getting the printers to operate at the right temperatures for different types of food is not easy. Food, unlike plastic, can change dramatically over a relatively short period of time: A batch of frosting made in the morning may work fine at one temperature, but the same batch later in the day may not. Now consider the huge array of possible ingredients and the different settings that each would need, and you can see why creating a truly useful home food printer seemed at first impossible. Then Cornell University graduate student Daniel Cohen had an idea.
What was needed, he thought, was the equivalent of an RGB standard for food. RGB stands for red, green, and blue, the basic color elements used in televisions to reproduce a rainbow of colors; a similar set of basic colors—cyan, magenta, and yellow—are used in inkjet printers. Cohen’s idea was to create a similarly standard set of elements for the food printer that would make it simpler to produce a variety of foods—and also allow you to share your designs, so that you could “send” a piece of cake to your uncle’s printer.
With Cohen and undergraduate students from Cornell’s school of hotel administration, we began to look for these few printable ingredients that could be used to build many different food types. We didn’t have to look far. A huge industry already exists to devise food flavors and colors that can make just about anything look and taste like something else. Supplements like vitamins, minerals, and fibers are also widely available.
The only problem, then, was getting the right texture. For that we turned to hydrocolloids—materials like carrageenan, xanthan gum, and gum arabic—that today appear on many food labels. They’re the thickeners in McDonald’s milkshakes, for instance. We brought in other gelling agents like those used in Jell-O desserts. We were already familiar with some of these substances, having used them to help print living cells. This time, we mixed the gels and gumming agents with other ingredients and then put them through our printer to create edible constructs like cubes of milk, raspberry domes, and mushroom-shaped bananas.
While these recipes demonstrated Cohen’s principle, they were also a little too weird. Offer someone a plate of banana mushrooms and milk cubes and you’ve entered the uncanny valley of food, where nothing feels quite right and everything screams “artificial.” Most home cooks aren’t ready to go there just yet.
Some researchers do see a future, however, in digitally designing food from basic flavors and supplements, in large part because it could be a more efficient way to produce nutritious but otherwise expensive food. Researchers at TNO (the Netherlands Organisation for Applied Scientific Research), are extracting basic carbohydrates, proteins, and nutrients from algae, insects, and the like and then using them to print something resembling steak and chicken. Eventually, this may allow them to print a filet mignon from a protein that requires far less water, energy, and labor than does a cow. TNO isn’t the only place exploring this realm. Susana Soares at London South Bank University has used a flour made from crushed bugs to print edible objects that look like butterfly wings and honeycombs.
While this approach could someday solve the Malthusian concerns of food production, it’s a hard idea to swallow. The trend these days is to back away from highly processed foods. Last year a number of huge meat-packing operations were shuttered after news about “pink slime,” a processed meat paste added to ground beef, hit the media. Who would want to risk their business on a pink-slime machine, especially if that slime comes from bugs?
Instead of designing foods from basic materials—from the bottom up—we’ve recently turned toward a top-down approach. That is, we’re taking existing foods and modifying them to make them printable. The idea came to one of us (Lipton) while flying back to New York after presenting a talk. While flipping through the in-flight magazine, he learned that David Arnold, a world-class chef, wanted to get his hands on a 3-D printer. We quickly arranged to send him a Fab@Home printer. In the first 24 hours of our collaboration with Arnold, we made deep-fried scallops shaped like space shuttles and sculptures made out of turkey with celery centers. Using the printer to creatively customize food shapes, we discovered, is a lot more appealing than crafting milk cubes out of hydrocolloids.
Inspired by Arnold, we then set out to push food printing even further. After all, anyone can use a mold or cookie cutter to shape food, but only a 3-D printer can easily create internal designs and intricate sculptures. We started with a recipe we got from Franz Nigl, a visiting scientist from the Pacific Northwest National Laboratory, whose Austrian grandmother’s Christmas cookies were notable for holding their shape when baked. We made batch after batch of the dough, cramming it into the printer’s cartridges and fine-tuning the recipes and the machine. We then programmed the printer to etch a message onto the top of each cookie, and eventually, we created a cookie that had writing inside it.
But message or no, a cookie is still a cookie. Our next stop was the International Culinary Center in New York City, where in January 2011 we began experimenting with food that could be made only by using a 3-D printer and that would be unlike any food we had ever eaten before, yet similar enough to avoid the “ick” factor. The result? A new form of fried corn dough. Now in a world in which state fairs offer up deep-fried Twinkies, you would think that there would be few frontiers left for fried or corn-based foods. But the 3-D printer has opened up entirely new ways of modifying textures. By printing meandering streams of our corn dough, we created a porous matrix that allowed the frying oil to penetrate much deeper into the food. The result was something delicately crispy and greasy, like a cross between a doughnut, a tortilla chip, and raw ramen noodles.
Our food explorations continue. Digital cooking is still a nascent field, but we’re amazed at how much progress has already been made: From those humble peanut butter, hummus, and chocolate objects, it has already morphed into a movement that could someday transform how we prepare and consume food. While some people believe the future of printed food will begin at the chemical level, others think it will become a common tool to augment the molds, knives, and ovens we already have. Regardless, both camps agree that the information age’s transformations have started making kitchen magic.
And once you get started, it’s hard to stop. To reward ourselves for finishing this article, we went back into the lab and printed ourselves a couple of cookies. To do that we ran software that considered our scheduled activities for the day, our food intake, and our individual heights and weights, and we then programmed our food printer to layer both sugar-free and sugar-rich dough to create a cookie that had just the right number of calories to fill out our calorie deficits for the day.
About the Author
Jeffrey Lipton was the project lead of Fab@Home, one of the first fully open-source 3-D printers, which in 2006 helped moved 3-D printers into the consumer market in general and into food printing in particular. Lipton is now chief technology officer of Seraph Robotics, a company that makes Fab@Home printers and parts; he’s also a Ph.D. student in Cornell University’s Creative Machines Lab. Hod Lipson is a professor at Cornell and the Creative Machines Lab and is coauthor of the book Fabricated: The New World of 3D Printing (John Wiley & Sons, 2013). When not making or eating printed food, Lipton and Lipson have a passion for advanced manufacturing and for as-yet-unprintable gastronomic miracles like doughnut burgers.