Moisture on Wet and Dry Bases: State the Denominator Before Comparing Percentages

Identify the Material Response

Mettler Toledo distinguishes moisture relative to initial sample mass from moisture expressed relative to the final dry mass. The denominator belongs in the reported result. Primary reference: moisture percentage bases.

Review a Hypothetical Comparison

For an invented water-only model, a sample contains 20 g water and 80 g dry solids. Water is 20 percent of the 100 g wet sample, but 25 percent of the 80 g dry solids. In fractional notation, x_dry = x_wet/(1 − x_wet); 0.20/0.80 = 0.25. Neither percentage implies that the composition changed.

Keep the Evidence with the Decision

Keep water or lost-mass identity separate from the calculation basis. Write the numerator, denominator and units before converting a supplier result. Ask whether the dry reference actually represents the defined dry solids or simply the endpoint of a particular mass-loss method. Preserve the method where that distinction affects the claimed quantity.

The simple conversion assumes the same water and dry-solid inventory in both figures. A measured loss containing other volatile matter cannot automatically be relabelled water by changing its denominator. These fictional masses are not a product moisture target or drying instruction. The practical output is a comparison table on an explicitly chosen basis, with the original supplier values retained for traceability.

Do two moisture figures use total sample mass or dry-solid mass?

This blank worksheet is for your own project. It contains no H M machine trial result.

Customer Questions

Primary References

These references support the technical principles discussed in this guide. The worked examples and review questions are educational.

• Primary reference: moisture percentage bases
• Reference from hmpharmamachines.com