ovendry

Ovendry describes a state of a material after it has been dried in a laboratory oven to a constant weight, removing all free moisture. The term is commonly used in soil science, food science, botany, and wood science to distinguish the dry mass from samples that are still moist or air-dried.

Typical procedures involve weighing a sample, drying it in an oven at a specified temperature (commonly around 105°C, though lower temperatures may be used for heat-sensitive materials), and continuing until the mass no longer changes between weighings. After drying, the sample is cooled in a desiccator and weighed again. The sample is considered oven-dry when successive measurements stabilize within a predefined tolerance.

Oven-dry weight is used to determine moisture content and to express dry matter. Moisture content is often calculated as the difference between the fresh or wet weight and the oven-dry weight, divided by the fresh weight, multiplied by 100. Oven-dry mass is also used in calculating other properties such as ash content, calorific value, and structural or nutritional measurements.

Limitations include the potential loss or alteration of volatile compounds and heat-sensitive constituents during oven drying. Some materials may decompose or react at elevated temperatures, or not dry uniformly if the sample is too large or heterogeneous. In such cases, alternative methods or lower temperatures may be required, and the choice of method should consider the material’s composition and the purpose of the analysis.