I noticed how thin the flakes on a supermarket black forest gateaux were and decided to measure the thickness.
So how do they make the chocolate flakes so thin? They're too clean to be shaved, so I reckon the chocolate is sprayed onto a continuous non-stick surface, cooled and then cracked off by going over a roller, the diameter of which probably affects the flake size.
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https://www.youtube.com/watch?v=kPTeZxCBxN8