Imagine coming down for breakfast and, instead of popping a piece of toast in the toaster and boiling an egg, you stick a cartridge in a printer. A minute or two later, you’ve got a freshly printed banana and flaxseed muffin.

Thanks to a new kind of 3D food printer, the printed breakfast is several steps closer to reality for the average consumer.

"Food printing may be the 'killer app' of 3D printing," says Hod Lipson, who’s led the creation of the new printer. "It's completely uncharted territory."

Lipson, a professor of mechanical engineering at Columbia University, has been studying 3D printing for nearly 20 years, working on printing things like plastics, metals, electronics and biomaterials. His work on 3D food printing came out of his research on printing complete 3D robots that could, in theory, “walk off the printer.”

To achieve something like this, a printer must be able to print with many materials at the same time. While experimenting with making multi-material printers, Lipson noticed the students in his lab were beginning to use food as a test material.

“They were using cookie dough, cheese, chocolate, all kinds of food materials you might find around an engineering lab,” he says. “In the beginning, it was sort of a frivolous thing. But when people came to the lab and looked at it, they actually got really excited by the food printing.”

So Lipson and his team began to take a more serious look at just what they could do with food. There are two basic approaches to 3D food printing, Lipson explains. The first involves using powders, which are bound together during the printing process with a liquid such as water. The second—the approach used by Lipson’s lab—is extrusion-based, using syringes that deposit gels or pastes in specific locations determined by the software’s “recipe.”

Lipson’s prototype involves an infrared cooking element, which cooks various parts of the printed product at specific times.

“We’ve used all kinds of materials, with different levels of success,” Lipson says. “Sometimes the materials are conventional—eggs, flour, cookie dough, cheese, pesto, jam. Cream cheese is something students like to work with a lot.”

They’ve also recently collaborated with a New York culinary school, letting chefs play around with the prototype to see what they’d come up with.

“They kind of broke the machine by really pushing it to its limits,” Lipson says. “One thing we’ve learned is printing in cream cheese is very easy, but printing in polenta and beets is very hard. It has these granules in it, so from an engineering standpoint it’s much more challenging.

It’s also difficult to predict how different foods will fare when combined. It’s easy enough to create recipes based on single items like chocolate, whose properties are well-established. But when you start to mix things together—mixing, of course, being fundamental to cooking—the mixtures may have much more complex behaviors. Another challenge is figuring out when to cook what during the printing process. If you’re printing a pyramid of salmon and mashed potatoes, the salmon and the potatoes will need very different cooking times and temperatures. The team is tackling this problem with software design, working with computer scientists to create software that will predict what the final product will look like after cooking.

The printer Lipson's team has made is not the only food printer to be developed in recent years. But while products like Hershey’s chocolate-printing CocoJet or the Magic Candy Factory’s 3D gummy printer are single-ingredient, limiting their use for the general public, Lipson’s printer is unique for being able to handle many ingredients at once, and cook them as it goes.

Lipson sees the printer as having two main uses for consumers. First, it could be a specialty appliance for cooking novel foods difficult to achieve by any other process. You could print, say, a complex pastry designed by someone in Japan, a recipe you’d never have the expertise or equipment to make by hand. Lipson says he could imagine digital recipes going viral, spreading across the globe. The second use is about health and targeted nutrition. People are already increasingly interested in personal biometrics, tracking their blood pressure, pulse, calorie burn and more using cell phones and computers. In the future, it may be possible to track your own health in much greater detail—your blood sugar, your calcium needs or your current vitamin D level. The printer could then respond to those details with a customized meal, produced from a cartridge of ingredients.

“Imagine a world where the breakfast that you eat has exactly what you need that day,” Lipson says. “Your muffin has, say, a little less sugar, a little more calcium.”

As for when the printer might be available to consumers, Lipson says it’s more a business challenge than a technology one.

“How do you get FDA approval? How do you sell the cartridges? Who owns the recipe? How do you make money off this?” he says. “It’s a completely new way of thinking about food. It’s very radical.”

A recent redesign of the prototype may bring the product closer to being something the average consumer would accept. Previous versions of the printer were very high-tech, full of tubes and sticking-out nozzles. People had a hard time imagining it on their kitchen counters.

Then, one of Lipson’s students named Drim Stokhuijzen, an industrial designer, completely redesigned the machine, giving it the sleek look of a high-end coffee maker.

“His design is so beautiful people are saying for the first time, ‘oh, I can see the appeal of food printing, this is something I might actually use,’” Lipson says.

Although Lipson doesn’t think 3D food printing will replace other cooking techniques, he does think it will revolutionize the kitchen.

“For millennia we’ve been cooking the same way,” he says. “Cooking is one of the things that hasn’t changed for eternity. We still cook over an open flame like cavemen. Software has permeated almost every aspect of our lives except cooking. The moment software enters any field—from manufacturing to communications to music, you name it—it takes off and usually transforms it. I think that food printing is one of the ways software is going to enter our kitchen.”