kuivapainoa

Kuivapaino, or dry weight, is the mass of a sample after moisture has been removed. It denotes values on a dry-weight basis, which allows comparison of a substance’s content independent of its water content. The term is used across disciplines such as chemistry, biology, agronomy, food science and environmental studies. In Finnish scientific literature, kuiva paino or kuivapaino appears whenever results are reported on a moisture-free basis to improve comparability.

Determination of dry weight is typically gravimetric. A representative sample is weighed, then dried in a drying oven at about 105°C until a constant weight is reached. After drying, the sample is cooled in a desiccator and weighed again. The final mass is the dry weight, and moisture content can be calculated as the difference between the initial wet weight and the dry weight. Constant weight is achieved when two successive weighings differ by only a small tolerance, often a fraction of a gram depending on sample size. For materials that are heat-sensitive or highly volatile, alternative methods such as freeze-drying or low-temperature drying may be used, and the chosen method should be documented to ensure comparability.

Applications of dry weight prevail in nutrition labeling, chemical analysis and biomass assessments. In agriculture and plant sciences, dry weight expresses biomass and enables comparison of yields independent of harvest moisture. In soils, dry weight is used for sample preparation prior to moisture determination and density calculations. Researchers and laboratories should report the drying procedure and conditions to ensure that dry-weight values are interpretable and comparable.