Kuivapaino

Kuivapaino, or dry weight, is the mass of a material after all water has been removed. It represents the solid portion of a sample and is used in fields such as food science, agriculture, chemistry, and pharmaceuticals. It is often considered together with fresh weight (tuorepaino) and moisture content.

Determination of kuiva pito involves drying a representative sample to constant weight. The common method is oven drying, typically at around 105 °C, until the weight stabilizes. Depending on the material, other methods such as infrared drying or freeze-drying may be used to minimize the loss of volatile components. The resulting mass is the dry weight.

Moisture content and dry weight are related through simple calculation. Moisture content can be expressed as a percentage: (initial mass − dry mass) / initial mass × 100%. The term dry matter or dry matter content (kuiva-ainepitoisuus) is often used in plant material contexts to refer to the proportion of dry matter present after drying.

Applications of kuivapaino include labeling and quality control, yield calculations in processing, and nutrition analysis on a dry-matter basis. In animal feeds and food products, expressing content on a dry-weight basis allows comparisons independent of moisture variation.

Important considerations include that the reported dry weight depends on the drying method and conditions (temperature, duration), and some materials may decompose or lose volatile substances during drying. To ensure comparability, standardized methods (such as AOAC or ISO procedures) are often employed.