Enzyme granules are used in laundry detergent formulations to improve washing quality at lower temperatures than commonly used with traditional formulations. However, any dust generated from their handling in manufacturing plants poses a health risk to operators. Therefore, current enzyme granule manufacturing produces strong granules that resist plant stresses and hence do not easily break. There are however indications that a very small number of granules are substantially weaker than the rest. This would have implications on the Coefficient of Variations (CV) of enzyme dust analysis. It is highly desirable to have a low value of Coefficient of Variation (CV) of enzyme dust to ensure confidence in the test results. The CV is largely influenced by the testing rig performance, but its minimum value is limited by the material characteristics. This work sets out to evaluate the minimum CV that is possible to get for the sample mass tested, by quantifying the number of outliers by impact testing using placebo granules. The outcome is a methodology for specifying the minimum possible CV that can be obtained from a given test material. (C) 2015 Elsevier B.V. All rights reserved.