Particle size control
The threshold is around 25 microns, and going far below it makes chocolate worse rather than better.
Human detection of grittiness begins somewhere around 25 to 30 microns, and refining exists to get every particle below it. That much is straightforward.
What is less obvious is that finer is not better. Reducing particle size increases the total surface area that cocoa butter has to coat, which raises viscosity substantially — an over-refined chocolate is thick, sticky and hard to work with, and reads as claggy rather than smooth. There is an optimum, and it is a range rather than a floor.
Particle size distribution matters as well as the maximum: a mix of sizes packs more efficiently and needs less fat than a uniform one.
What it does
Sets the size and distribution of solid particles suspended in the fat phase, determining both perceived smoothness and viscosity.
Why it matters
It is the single determinant of whether chocolate feels smooth, and it trades directly against how easily the chocolate flows.
When it goes wrong
Under-refining gives grit; over-refining gives excessive viscosity. Both are failures of the same control.
Related
Covered in
- Particle size and smoothnessThe measurement and control step this guide is about.
- Why chocolate is grainyThe manufacturing stage that determines whether a bar is smooth.
Sources
- ChocolateHQ editorial synthesis — ChocolateHQ(citation identity confirmed; passage not re-read)
- The Science of Chocolate — Royal Society of Chemistry(citation identity confirmed; passage not re-read)