Chocolate is manufactured by first roasting cocoa beans and passing the nibs through a roll refiner before moving to the tempering stage. The refiner grinds the nibs into smaller particles, melting the cocoa butter. The human mouth detects chocolate with particles larger than 30 microns as gritty. The ideal particle size is close to 20 microns for chocolate with a creamy texture when consumed.

A chocolate manufacturing facility wanted to examine the effect that refiner roll grind quality had on the quality of chocolate. The surfaces of rolls in a chocolate refiner wear with use over time and need to be reground. Two chocolate refiners were studied to determine the quality difference between refiner rolls ground by Precision Roll Grinders (PRG) and another machine with rolls ground to a standard grind. The Precision Roll Grinder rolls were ground with a focus on tight geometric tolerances for profile, roundness, and surface finish.

The refiner with PRG precision ground rolls produced chocolate with 90% of the chocolate particles smaller than 22 microns. The chocolate produced with standard ground rolls produced chocolate with 90% of the chocolate particles smaller than only 29 microns. Particle sizes close to 30 microns cause the chocolate to taste gritty, while particle sizes close to 20 microns give chocolate a creamy texture when eaten. The refiner with the PRG rolls produced chocolate samples with fewer large particles, a property associated with higher-end, luxury brand chocolates with creamy textures with no gritty taste.

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