Calculating Dehairing Yield Mass Balance across High Guard Hair Batches
Calculate dehairing yield by converting raw mass to clean dry keratin weight, subtracting guard hair and dirt losses, and normalizing to 17% commercial regain.
Coarse Hair Medullation
Fiber Structure
Hollow central cores consisting of spongy, air-filled cells in specialty animal fibers run along the longitudinal axis of the hair shaft and reduce the overall density of the material. This internal void is known as coarse hair medullation, and it occurs predominantly in coarser wools, cashmere, and alpaca fibers.
Dyeing Impact
Light reflection from the air-filled internal cavities of the fiber alters the visual appearance of dyed yarn by making it look lighter than solid-core fibers. Because of coarse hair medullation, dyed fabrics may display a frosty or uneven color distribution that cannot be corrected by longer dye cycles. To mitigate this effect, mills often route medullated fibers into un-dyed, natural yarn lines where the physical structure adds to the rustic texture of the finished garment.
Laboratory Assessment
Optical microscopy remains the primary standard method to identify and count the percentage of fibers containing hollow cores. Under a projection microscope, coarse hair medullation appears as a dark central channel when the fiber is immersed in a liquid of matching refractive index. Laboratories calculate both the percentage of medullated fibers by count and the average diameter of the medulla relative to the outer fiber boundary.
Modern image analysis systems automate this count, scanning thousands of fibers in minutes to provide a reliable measure of the lot before yarn spinning begins.
Raw Material
Selective breeding programs in sheep and goats aim to minimize the presence of hollow fibers to improve yarn softness and spinability. Raw fiber specifications often set a strict maximum percentage for coarse hair medullation to ensure that the purchased wool or cashmere meets high-end apparel standards.