About Wool Fibers

Wool is the fiber of the sheep fleece, and it is the standard against which other animal fibers are judged. A wool fiber is a protein strand with a scaled surface and a natural wave called crimp, and those two structures explain almost everything wool does: the scales let fibers lock together in felting and hold moisture vapor, while the crimp traps air for insulation and gives wool yarn its spring, resilience and resistance to crushing.

Wool is also a family, not a single grade. At one end, long coarse fibers go to carpets, tweeds and blankets; at the other, the fine merino fibers covered on their own page in this directory go against the skin. Between them sit the lambswool, crossbred and medium wools of knitwear and suiting. Grading — by fiber diameter, length, color and cleanliness — is the trade that sorts one fleece into all of those markets.

Shearing, Scouring and Grading

Sheep are shorn, usually once a year, and skilled shearers remove the fleece in one piece. The fleece is skirted — the stained and coarse edges removed — and classed by its fineness and length, then scoured in hot detergent baths that strip out the grease (lanolin), sweat salts and dirt that can make up a surprising share of a raw fleece weight. The recovered lanolin is itself a product, refined for cosmetics and ointments.

Clean wool is carded to open and align it. From carding, the road forks: woolen spinning keeps fibers in a lofty, mixed-length web and spins soft, fuzzy, insulating yarns for blankets, tweeds and knitwear, while worsted spinning combs the fibers parallel, removes the short noils, and spins smooth, strong, lustrous yarns for suiting and fine flat knits. The same fleece region can feed both systems at different grades.

Warmth, Resilience and Felting

Wool absorbs a large amount of moisture vapor into the fiber core before feeling wet, and the absorption releases a small amount of heat, which is why wool clothing buffers its wearer so well in changing weather. The crimped fibers resist packing down, so wool carpets, knitwear and insulation spring back underfoot and in wear, and wool is naturally slow to burn — it chars rather than melts, a safety property synthetics cannot copy.

The famous weakness is felting: heat, moisture and agitation ratchet the surface scales together and the fabric shrinks irreversibly into felt. The industry answers in two directions — shrink-resist treatments that coat or smooth the scales for machine-washable wool, and deliberate felting for hats, boots, industrial felts and craft cloth, where the same behavior is the product. Moths, the other classic enemy, are managed with modern mothproofing and clean storage.

Where Wool Is Used

Wool runs from fine worsted suiting, dresses and trousers through knitwear, blankets, upholstery, carpets and rugs to industrial felts and insulation. Blends tune it constantly: nylon for abrasion in socks and carpets, polyester for cost and durability in suiting, cashmere or silk for luxury hand. When sourcing, the useful specification is the grade — fiber diameter range, staple length, woolen or worsted route, and shrink treatment — because the single word wool covers cloth at every price from carpet squares to bespoke suiting.