Why some chocolate feels gritty
The tongue stops detecting individual particles somewhere around 25–30 microns. Everything about chocolate texture follows from that threshold.
If you read nothing else
Smoothness means getting particles below about 25 microns. Finer is not automatically better — it costs cocoa butter and can read as pasty — and apparent grittiness is often sugar bloom instead.
The threshold
Human oral texture perception detects particles down to roughly 25–30 microns; below that, a suspension reads as smooth. Chocolate refining exists entirely to get sugar and cocoa solid particles under that line.
A well-refined chocolate typically runs around 18–20 microns. Traditional Mexican drinking chocolate might be several hundred, which is why it feels grainy — and in that tradition the grain is characteristic rather than a fault.
Why smaller is not simply better
Grinding finer increases the total surface area of solids, and every bit of that surface needs coating in fat. Below about 15 microns the chocolate becomes very viscous and needs extra cocoa butter to flow at all, which is expensive.
Very fine particles can also read as pasty rather than smooth. There is an optimum rather than a monotonic improvement, and it sits in the high teens for most eating chocolate.
What causes grittiness in practice
Under-refining is the obvious cause, and it is why craft bars from small melangeur operations are occasionally slightly grainy. Sugar type matters — some alternative sweeteners and unrefined sugars are harder to grind down.
The other common cause is not grittiness at all: sugar bloom. Chocolate exposed to condensation dissolves surface sugar, which recrystallises as a rough layer. That feels gritty and is a storage failure rather than a manufacturing one.
Covered in this guide
- Particle size controlThe measurement and control step this guide is about.
- RefiningThe stage that reduces particle size.
- ChalkyThe sensory descriptor most often used for the fault.
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)