dewretting

Dew retting, also called field retting, is a natural fiber extraction method used for bast fibers such as flax and hemp. In this process, harvested stems are laid out on the ground where dew, humidity, and native microorganisms weaken the pectic substances that bind the fiber to the woody core. The goal is to loosen the fiber bundles so they can be separated by subsequent processing.

After harvest, the cut stalks are arranged in rows or windrows and left to rett for several days to weeks, depending on weather. Moisture from dew and ambient warmth promotes microbial action that hydrolyzes pectin and other gummy materials. Retting completeness is judged by ease of fiber release from the core. Prolonged retting can weaken fibers, whereas under-retting reduces separability. Once retting is adequate, the material is dried and subjected to mechanical decortication, scutching, or hackling to separate and align fibers.

Advantages of dew retting include low direct water use and relatively low chemical input, making it inexpensive and suitable for small-scale production. Its main drawbacks are weather dependence, variable results, odor from decaying plant matter, and potential environmental concerns if effluent is not properly managed. In modern industry, dew retting is often supplemented or replaced by water retting or chemical methods in larger operations, though it persists in traditional linen production and niche applications.

History and scope: Dew retting has been practiced for centuries in Europe and parts of Asia for flax and other bast fibers. Today it remains associated with artisanal and regional textile production, where climate and farm practices can favor sustainable, low-energy fiber extraction.