How should grind-size repeatability be tested on a commercial coffee grinder?

Use one coffee-bean lot for repeated grinding trials and compare target particle range and distribution stability over time. For multi-product use, test representative low, medium, and high operating points to reveal the available adjustment range. If several specifications are required, document each setting so future operators can reproduce the approved process. Do not accept an unspecified “maximum capacity” claim when the real application requires a defined quality level. This information also helps the buyer estimate utilities, staffing, spare parts, and expected maintenance requirements before installation.