Samy Kamkar, an internet security company owner with a food hobby, successfully molded iridescent chocolates with the help of a 3D printer, vacuum chamber, and some simple physics. The chocolate’s rainbow shimmer requires no special ingredients, dyes, or pigments and is completely safe to consume.
To create iridescence, an object’s physical structure must make light waves combine with each other causing what is called "interference.” Using a 3D printer, Kamkar made a mold that contained micrometer-sized features, or diffractions, in its surface to pour the chocolate into. Then it went into a vacuum chamber to prevent bubbling. Kamkar noted that the “micro-texture” of the chocolate had no effect on the taste or mouth-feel. He said tempering, the process of heating and cooling chocolate for shine, could help maintain the texture.
This is not a new idea, however; researchers in Switzerland filed for a patent for “shimmery, iridescent chocolate” to be produced and sold commercially. Iridescence can be created using this technique but is also something that can be found on its own in nature on animals like hummingbirds, butterflies, and peacocks.
