Retting
Also searched as: dew retting, field retting, water retting
Breaking down the tissues that bind bast fibers to the stem, using an appropriate biological or processing route.
In detail
Retting loosens the tissues that bind useful bast fibers within a plant stem. European flax production commonly uses field retting, where natural conditions and biological action help make the fibers separable. The process prepares stems for mechanical extraction rather than producing finished yarn.
The science and numbers
In a bast stem, fiber bundles are held to the surrounding tissues and the woody core by pectin-rich middle lamellae and hemicelluloses. Retting microbes secrete pectinases and xylanases that break down these cementing polysaccharides while, ideally, leaving the cellulose of the fibers intact. In dew retting, pulled flax lies in swaths and aerobic plant-degrading fungi colonize the stems in succession, with Cladosporium and Alternaria prominent, alongside bacterial communities that high-throughput sequencing studies now follow through the process. Water retting is anaerobic and bacterial, traditionally driven by Clostridium species that ferment pectin to organic acids. Timing is the critical control: under-retted stems resist mechanical separation, while prolonged retting allows microbial attack on the fibers themselves. Research on enzyme treatments and on inoculating dew-retting flax with Bacillus strains aims to make the process faster and more uniform.
A practical example
A flax journey may show pulling, retting and then scutching. Read those as distinct transformations: harvesting the stem, loosening binding tissues and separating the usable fiber from woody material. Keeping them separate makes processing descriptions easier to follow.
What to distinguish
Retting practices depend on crop and production route. Do not assume that every bast fiber is water-retted or that a process name establishes its water, energy or pollution impacts.
Origins and history
The verb ret entered English in the medieval period from Middle Dutch reeten, with relatives in Middle Low German roten and Old Norse reyta, traced to a reconstructed Proto-Germanic verb meaning to make soft or mellow. Merriam-Webster dates the first known English use to the 14th century. The word therefore names the purpose of the process, softening stems until fiber can be freed, rather than one method, and it covers both field (dew) retting and retting in ponds, rivers or tanks.
Related terms
Sources & further reading
- Alliance for European Flax-Linen & Hemp: Flax growing and expertise
- PMC: Targeted Metagenomics of Retting in Flax
- Applied and Environmental Microbiology: Identification and retting efficiencies of fungi isolated from dew-retted flax (1997)
- PMC: Characterization of Bacterial and Fungal Community Dynamics by HTS Metabarcoding during Flax Dew-Retting
- Merriam-Webster: Retting definition and meaning
Technical references reviewed 2026-09-22. Examples are illustrative. Industry organizations and manufacturers describe their own fields; their references are not independent product endorsements. Figures are approximate and depend on the stated test conditions.