The sample material is weighed and placed into a sample tray. The sample tray itself is part of an integrated reactor within the HydroTracer. A heater warms the sample to the selected temperature. The water evaporating from the sample reacts with the powdery reagent in a cooled area and water is transformed into hydrogen. The concentration of hydrogen gas is measured. It is a measure for the amount of water in the reactor.
The concentration of hydrogen is a measure of the sample humidity. The percentage of water of the sample is calculated by division with the sample weight.