Wool Defined

What Wool Is

Wool is the textile fibre obtained from sheep and certain other animals, including cashmere and mohair from goats, qiviut from muskoxen, and fibre from alpaca and camel. Its usefulness begins in its structure: the fibre's surface carries overlapping scales, and it grows with a natural waviness called crimp. Scaling and crimp make the fleece easier to spin, because the fibres attach to each other and stay together as they are twisted into yarn.

Crimp also explains much of wool's behaviour in fabric. Because of the crimp, wool fabrics have greater bulk than other textiles and trap still air, which is what makes them insulate. Insulation works both ways: wool holds body heat in cold weather, and traditional desert clothing uses wool to help keep heat out. The amount of crimp corresponds to the fineness of the fibre, so a fine wool such as Merino may have up to around a hundred crimps per inch, while a coarse wool such as karakul may have as few as one or two.

Not everything on a sheep is wool. The straighter, hair-like part of the fleece is called kemp, and hair has little scale or crimp and little ability to bind into yarn. The balance of kemp and true wool varies by breed and helps decide whether a fleece suits spinning, felting, or carding into batts for quilts and other insulating products.

How Wool Behaves

Wool fibres readily absorb moisture, taking up almost a third of their own weight before they feel wet, and the fibre's structure gives wool cloth its characteristic resilience and warmth even in damp conditions. Wool also absorbs sound, which is one reason wool carpets and hangings quieten a room. Most wool is a creamy white colour, although some breeds produce natural black, brown and silver fleeces and random mixtures of shades, which growers of naturally coloured wool value for undyed yarns and fabrics.

Fire behaviour sets wool apart. It ignites at a higher temperature than cotton and some synthetics, spreads flame slowly, releases little heat, and does not melt or drip. Instead it forms an insulating char that tends to extinguish itself, contributing less to toxic gases and smoke than many flooring products. Wool carpets are therefore specified for trains and aircraft, and wool is used in garments for firefighters and soldiers.

These properties come with care obligations. Wool's scales can lock together permanently under heat, moisture and agitation, which is felting: desirable in a felt hat, disastrous in a machine-washed sweater.

From Shearing to a Priced Lot

Shearing is the process by which the woollen fleece is cut from the sheep. After shearing, the wool is separated into categories, with the fleece making up the vast bulk, alongside broken pieces, bellies and locks. Quality is then determined by wool classing, in which a qualified wool classer groups wools of similar grading together to maximise the return for the farmer. In Australia and New Zealand, Merino fleece wool is objectively measured before auction for micron, yield including vegetable matter, staple length, staple strength and sometimes colour and comfort factor.

Wool straight off the sheep, known as greasy wool, contains valuable lanolin together with dirt, dead skin, sweat residue and vegetable matter, so it must be scoured before commercial use. Scouring can be as simple as a bath in warm water or as involved as an industrial process with detergent, alkali and specialised equipment, and in commercial wool, vegetable matter is often removed by chemical carbonisation. Lanolin recovered in scouring is widely used in cosmetic products such as hand creams, and gentler processing that leaves some lanolin in place produces the semi-grease wools used for notably water-resistant hand knits.

Global wool production is approximately 1.3 million tonnes per year, of which about sixty percent goes into apparel. Australia is the leading producer, mostly from Merino sheep; New Zealand is second and the largest producer of crossbred wool; China is third. Coarser wools from breeds such as Lincoln, Romney and Drysdale usually go into carpets, while large United States flocks in Texas, New Mexico and Colorado are based on the Rambouillet.

What Decides Wool Quality and Price

The quality of wool is determined by fibre diameter, crimp, yield, colour and staple strength, and fibre diameter is the single most important characteristic determining both quality and price. Diameter, measured in microns, decides what a wool can become: the finest wools make soft next-to-skin apparel, mid-range wools make durable knitwear and suiting, and the coarsest make carpets and rugged outer cloth. A buyer who knows the micron of a lot already knows most of its likely market.

Pricing knowledge alone is not enough. If you want to buy wool and negotiate a fair price, understanding the product matters as much as knowing the current asking price. A cheap lot with low yield, short or tender staple and heavy vegetable matter can cost more per usable kilo than a dearer, cleaner, stronger lot, and only the specification sheet reveals that before the money is spent.

The industry bodies in the references support that knowledge, covering the auction, testing and innovation systems of the largest producing country and the United States industry.