Jonathan Blutinger and his team at Columbia University can make an impressive, layered graham-cracker cake.

While delicious, according to Chef Blutinger, the dessert is also noteworthy because of the tools used to make it:

Lasers and a 3D printer.

With the help of additive-manufacturing techniques and software-controlled lasers, Blutinger and his colleagues are digitizing the cooking process.

The combination of 3D printers and photonics allows temporal and spatial control of the cake's ingredients: graham-cracker paste (a combination of crackers, butter, and water), as well as peanut butter, jelly, Nutella, banana, frosting, and cherry drizzle, says Blutinger.

"We could precisely control the amount of each of the ingredients, which would affect the overall texture and perceived flavor profile of the food," Blutinger told Tech Briefs. "We can change the location of the ingredients being layered internally, and the pooling of these ingredients, which also changes the sensory experience."

While food printers have the ability to deposit materials to millimeter-scale resolution, the printers do not yet have the ability to cook foods to this same degree of resolution. Integration of a multi-wavelength laser cooker onboard a food printer can provide both penetrative heating and surface browning.

In a new study published Sept. 1, 2021 by npj Science of Food , the Columbia researchers cooked chicken with blue light (445 nm) and infrared light (980 nm and 10.6 μm). Compared to conventional cooking methods, the team's study demonstrated that the 3-mm-thick chicken samples shrunk 50% less during the cooking process and avoided being dried out.

"We found that we actually can retain more of the moisture content of the food as opposed to dry air heating in an oven," said Blutinger.

Ovens, stovetops, and microwaves cook food with a uniform temperature. Lasers offer more control over heating.

By tuning parameters such as circle density, circle diameter, path length, and laser speed, the researchers can optimize the distribution of energy that hits the surface of food.

"You need a lot more precision when you're cooking through different foods if you want to really leverage all the resolution that they can afford you," Blutinger told Tech Briefs.

Different wavelengths of light can cook food to different depths. Blue lasers, for example, are best for penetrative cooking, says Blutinger, while infrared lasers support a kind of browning effect. Multiple wavelengths should be combined for best results, according to the researchers.

In a short Q&A with Tech Briefs below, Blutinger talks about the "inevitability" of lasers in the kitchen.

Tech Briefs: What inspired you to start cooking with lasers?

Jonathan Blutinger: With lasers, it really was more of a question of: Can we cook food using software? Then, as we explored this topic, we got into 3D printing, which first started in our lab around 2007.

Tech Briefs: What kinds of food did you start with?

Jonathan Blutinger: More recently we explored chicken, which is a higher-risk ingredient because you need to actually cook it to a food-safe temperature to eat it so that there's no bacteria or anything like that.

Tech Briefs: So what's better about, say, cooking chicken with lasers compared to cooking from conventional methods? What's possible with laser cooking that you can't get from conventional methods.

Jonathan Blutinger: It's just all about customization and control. When you cook with lasers, you can get a lot more control over browning or baking. You can get different modes of cooking within the same type of food. We can change the wavelength or change the speed. There's just a lot more variables we can tweak and tune, and we're able to cook things at a much closer level. You can do subsurface cooking.

Tech Briefs: Using chicken as a specific example, what kinds of customization is possible for that?

Jonathan Blutinger: You can do a more controlled browning of the surface. You can retain more moisture. You can also brown foods within their hermetically sealed package. If you can cook and brown the food within the packaging, then you can eradicate more of the bacteria from within the package while maintaining a much longer shelf life. We haven't yet looked at bacterial growth but it's something we'd like to explore in the future.

Tech Briefs: Can you help me visualize the technology setup that enables this kind of application?

Jonathan Blutinger: The setup right now is basically a 3D-printing gantry, which is about 2' x 2' x 2' roughly in footprint — something that can fit on a large kitchen counter. It looks a little bit like a torture device right now, but it’s a machine that can have a host of different food capsules on the front of the machine. The machines can pick up one of these food capsules, print with it, and then there are two lasers mounted to the side of the machine. There's an infrared laser and a blue laser. Most of the lasers we use are something you can hold in your hand — so, it's about the size of a water bottle.

Laser cooking in process. (Image Credit: Blutinger)

Tech Briefs: Do you envision a kind of future of laser cooking and a kind of "food CAD?"

Jonathan Blutinger: I think the future for this technology is pretty interesting. Right now there aren't many ecosystems that can support it. By that I mean we pretty much created an iPod, but we don't have any MP3 files to play music. There's going to need to be software to support it, basically. There will need to be places where you can actually design the foods and create these novel recipes inside some kind of app or kind of consumer-facing products or software. You need an ecosystem to support the manufacturing of the tool cartridges — the tool for the food capsules — and the recipes, which would be in kind of an “iTunes Store,” or on a Spotify-type list of recipes that you can download and upload to your machine, to create more of the social and digital landscape to support the technology.

Tech Briefs: So, the futuristic idea is that somebody can take digital file, a kind of recipe, and then print the food?

Jonathan Blutinger: It can happen in a number of ways. I think, for one, you're going to have people who are makers, who are just going to be devoted to tinkering and coming up with new recipe files.

Then, we're going to have people who are mostly more consumers, who are going to be basically downloading files that have been made by other people. When someone makes a file and, say, you try it on your machine, you can easily kind of give it an “upvote” or “downvote” rating.

I think you'll start to find venues to make more of these recipes. I can envision a system where you're watching TV one day, and then there's a message on your local channel that says: "If you want to check out this new recipe, scan this QR code.” And then the QR code automatically orders the recipes for you, or it downloads the recipe file for you, uploads into your machine, and it starts printing it.

Tech Briefs: So the ingredients go into this machine? They're just the kind of ingredients that you would have in a grocery store.

Jonathan Blutinger: Correct. You literally just go to the grocery store, and you find want you want to print with. Then, the only kind of pre-processing we'll do is either blend it or get it into a form that makes it kind of like a paste — almost like the texture of cream cheese or peanut butter. That’s the ideal rheology we're shooting for, with the ingredients we want to use. We’re also working on depositing powders, liquids, sprays, and oils, so we're trying to make it as adaptable to our current cooking as possible.

Tech Briefs: What has been the most delicious thing you've tasted out of this technology?

Jonathan Blutinger: A lot of the things we’ve been doing recently have been more confectionery, like sweet things, because they're easier to print. We made a pretty good 7 ingredient graham-cracker cake. It was probably one of our most successful multi-ingredient prints, and that that took a number of iterations to actually finally be successful.

But even with the iterations when you have failures and prints, you still have good ingredients. So those don't go bad. It'll still taste good even if the prints might not look the nicest.

Tech Briefs: Is the tech "there yet," or is there something that still needs to kind of be tweaked and adjusted for it to work most effectively.

Jonathan Blutinger: I would say that the hardware is there. I think the bottleneck right now is the software piece, which is what I'm working on a lot with my team: the engine that converts 3D models into actual digital recipes for our machine.

That's because our machine right now is entirely open loop. By that, I mean there are no sensors. There's no feedback that we get. We are the sensors. Our code needs to be really robust, and our files generally go through a lot of iterations for this reason, because we have a lot of failure. If we can place more sensors on our machine to make it “smarter,” we will improve this process, but the technology is here. It’s a matter of piecing it all together at this point, and making it a little more seamless.

Tech Briefs: What would you say is the most common response where it requires that you do some convincing?

Jonathan Blutinger: I think the word “printing" is a hard word for people to associate with food, so I like to use, you know, “assembly” or “digital cooking.” There are certain mental leaps that people have to make when they think of printing, because they usually associate it with, you know, Xerox machines or just making copies on an old fashioned printer.

I just think educating people a little bit and kind of reminding them that we're not like using processed foods or anything. By "process" I literally mean just processing it. We're using all the same ingredients that you cook with in your kitchen, so just making sure it’s familiar for people, which is which will only happen with time.

Tech Briefs: Is laser cooking an inevitability?

Jonathan Blutinger: I think food is a really emotional topic. It's almost like a like a religion in that way, in that we're very particular about our eating habits. Everyone has a different customized way that they like their food prepared so it only seems natural to me that, once you infuse software into it, you just get total control.

I think the fact that a lot of people are irked by this technology makes it even more exciting to work on, because it almost is a challenge to try to convert them, and it also kind of affirms for me how novel it is.

But I think it's an inevitability. I think as robots are starting to pervade our kitchens and make things more automated, people will see it's kind of the only way. It's kind of the only next step forward.

What do you think? Would you laser-cook? Share your questions and comments below.