Environmental Cause
Natural exposure to moisture and fungal colonization on the field ground allows the separation of bast fibers from the woody flax stem. This process introduces dew retting variability because local weather conditions, particularly rainfall and humidity, fluctuate throughout the harvest season. Fungal species require specific moisture levels to secrete the enzymes that break down pectin.
When weather patterns diverge from historical averages, some sections of the crop under-ret while others undergo over-retting, creating non-uniform fiber batches.
Processing Impact
Downstream spinning operations face operational challenges when raw material attributes change between bales. Such dew retting variability results in unpredictable drafting force requirements and increased yarn hairiness because unevenly retted fibers do not separate cleanly. Over-retted fibers become weak and brittle, leading to a high proportion of short fibers that accumulate as waste during the carding stage.
Conversely, under-retted fiber bundles remain coarse, which causes frequent sliver breaks and prevents the spinning of high count yarns.
Industrial Grading
Quality control laboratories evaluate each incoming batch using mechanical testing to categorize the fibers. The level of dew retting variability is recorded on the raw material receipt ledger. This assessment dictates how bales are blended to prevent dyeing faults in woven linen.
