107: Chocolate Rheology and 3D Printing

Chocolate is the most popular candy produced in the world. Traditionally, it is presented as bars or nuggets, or molded and sculpted with a great deal of manpower and time. However, with an accessible 3D printer, people could create a custom chocolate figure at a much lower price. Our objective was to design and optimize a procedure to adapt an inexpensive 3D printer to “print” chocolate structures and establish a standard procedure to do so.

Chocolate is a delicate science, and its various crystalline structures can be lost past a certain temperature. The substance is a polymorphic, non-Newtonian fluid, making it an excellent 3D printing filament. We used a Creality Ender 3 printer with a Wiibox LuckyBot Food Extruder to combat clogging.
We used dark chocolate because it has fewer ingredients and higher cacao content, increasing its viscosity and making it better for printing. As a final product, we decided an acceptable print would be judged qualitatively and quantitatively for structural integrity and clean layers. To prepare chocolate to print and characterize, it must be melted—but kept below a temperature threshold. Otherwise, it will permanently lose its crystalline structure. We used an immersion heater to establish a standard tempering procedure and temperature. We then transferred the chocolate to either the printer for trials or the rheometer for characterization. To optimize our printing procedure, we characterized the chocolate with rheological studies, adjusting variables and optimizing our printing and tempering processes. We also used a cold plate to cool the chocolate after printing.

Our findings contribute to research on 3D printing alternative materials, specifically food. Chocolate companies are already funding research on 3D printing their products, but for just a few hundred dollars, we are doing the same.