throughdrying

Throughdrying, or through-drying, is a drying process in which moisture moves through the interior of a porous material to the exterior, where it is removed. This contrasts with surface-drying methods that shed most moisture from the outer layers. In through-drying, interior moisture diffuses toward the surface under the influence of temperature, humidity, and airflow, creating a cross-sectional moisture gradient rather than drying being confined to the surface.

The rate and uniformity of through-drying depend on material properties such as porosity and grain structure, initial moisture content, and environmental conditions including temperature, relative humidity, and air velocity. High diffusivity and adequate airflow promote interior moisture migration, while overly aggressive conditions can cause surface checks, internal stresses, or uneven drying if the interior remains wet while the surface dries too quickly.

In wood processing, through-drying is used to balance moisture throughout the thickness during kiln or conditioning cycles, aiming to reduce internal stresses and improve dimensional stability. In papermaking and some textile processes, through-drying refers to drying approaches that move moisture through the sheet or fabric, sometimes described as through-air drying, which can improve energy efficiency and dryness uniformity.

In ceramics and brick production, through-drying seeks uniform moisture removal to prevent warping and cracking. Achieving even drying requires careful control of environmental conditions, humidity, and drying schedules tailored to the material and geometry.

See also: drying, diffusion, kiln drying, through-air drying.