This project from the early days of my PhD (December 2012) is part of my ongoing effort to publish previous work.
When I started this project, I was relatively new to 3D printing. I had been exploring materiality and deposition techniques as a Master’s student for a couple of years, testing materials with different viscosities and behaviors, such as wax and play-dough.
Experimenting with food printing seemed like an exciting direction to explore. It was also the perfect occasion to test a newly prototyped syringe-based extrusion system.
While this ended up being more of a food decoration experiment with a 3D printer than a 3D printing experiment itself, it proved to be a great learning opportunity.
The idea was to deposit a single layer of viscous sugar-water mix on top of a flat surface made of chocolate. The aim was to prove the versatility of the system with other-than-plastic materials. I am sad that I did not document the process properly and that I did not keep any of the data; the only thing remaining is some early development sketches and pictures. The process was loosely planned in advance and then freestyled and adjusted along the way.
Machine set-up
I used an awfully unreliable and noisy Prusa Mendel, which was built previously in our lab at the Technical University of Denmark. I replaced the conventional heated nozzle with a 10 ml medical syringe and placed it on a custom-designed mounter, printed with ABS plastic on the machine itself. The plunger was also replaced with a smaller insert, also 3D printed. The extrusion principle was simple: a 3mm ABS filament, driven by a stepper motor, pushed down the modified plunger. This was nothing I had invented, but rather one of the many versions of paste-extruders that were circulating online at the time, something I downloaded and adjusted to fit it on one of the labs’ machines.
Materials
The process of mixing the water with sugar to create the extrusion material was more intuitive than scientific. I was adding water gradually to the sugar until I reached a texture I was happy with, neither too liquid nor too solid, something resembling toothpaste. As a deposition base, I used some pre-cut thin dark chocolate “sheets,” a popular treat among Danish kids, and arranged them on top of the existing build plate.
Software and printing
I do not remember what software I used for designing the single-line, Christmas-inspired geometries, but they were made only 0.5 mm tall, ensuring the slicing software would convert them into single-layer patterns. For preparing the file, I used the good old Slic3r.
When everything was ready, I filled the syringe manually with the sugar-water solution and inserted the shortened plunger at the back of the syringe. Then, I positioned the ABS filament into it. Rather than being melted and extruded, the filament simply applied force to the back of the plunger to extrude the glazing. The machine was interfaced to my computer with a software called Pronterface (now called Printrun?). Again, I did not keep the parameters I used for running the jobs.
Now, I would love to tell you that I am a person with judgment and that I didn’t touch the stuff for food safety reasons, but alas, I tasted the thing and even shared it with colleagues. The syringe was clean, and I covered the build plate of the machine with baking paper, but I will not go into the details of the rest because *cough* I can’t remember *cough*. Let’s move on?
Final thoughts
Food printing remains a niche field, and I’m proud to have been a contributor. Though I’m no longer participating as a scientist or conducting exciting experiments, it’s a topic I still follow with fondness and curiosity. I’m still surprised that the technology hasn’t advanced significantly beyond decorative applications, and even then, it hasn’t achieved major commercial success.
But I understand why. The ingredients that can be 3D printed as food are limited, and the textures that can be replicated are equally constrained, if not practically non-existent. The eating experience itself becomes limited and perhaps unappealing to most people. The results are typically mushy and oddly textured.
As always, there are exceptions. While doing a last-minute research for wrapping up this blog post, I was reminded that an Austrian company is using 3D printing to mass produce vegan fish alternatives (Revo Foods). They integrate fats into a protein fibrous mix, taking advantage of the controlled, multi-material deposition for creating a meat-like texture. Interesting! There is even an online shop where a vegan salmon retails for a reasonable price (31 DKK per May 2025). This may call for an experiment.
There are other applications like customized nutrition for the elderly or athletes that have been discussed academically, but even here, 3D printing feels more like a technical challenge or marketing gimmick than a commercially viable solution at scale. I’d be genuinely interested in talking to someone who has considered the business models. I’d love to understand the numbers behind these ventures. So far, I struggle to see where 3D printing adds value specifically in these cases. It seems like there would be much cheaper and faster solutions for customized nutrition that don’t involve the complexity of 3D printing technology. My intuition suggests that if you are an elite athlete who requires precise nutritional planning, you wouldn’t print your protein bars on demand, one at a time. Or at least I wouldn’t, I think? Unless I am missing something, if I am, please let me know.
Regardless of market perspective or commercial value, I had a lot of fun experimenting with food printing, and one of the experiences from my PhD that I remember with great fondness.
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