Wool

Wool is the textile fiber obtained from sheep and other mammals, especially goats, rabbits, and camelids.^[1] The term may also refer to inorganic materials, such as mineral wool and glass wool, that have some properties similar to animal wool.

Wool is an animal fiber and consists of protein together with a small percentage of lipids. This makes it chemically quite distinct from cotton and other plant fibers, which are mainly cellulose, and akin to silk, another animal fiber composed primarily of protein.

Today the largest market for wool is for wool from sheep.^{[citation needed]} Wool's unique characteristics have made it highly valuable for clothing and textiles. It has a long history being used for apparel and other items while fueling trade and economic growth in many countries. Wool is still used in clothing today and is often mixed with other fabrics. After being shorn, wool must be processed in order to be turned into its desired product, and it is still largely important for textiles both privately and commercially, and is even used in art.

Wool is most commonly obtained from sheep. It is generally a creamy white color, although some breeds of sheep produce natural colors, such as black, brown, silver, and other random mixes. Wool is produced by follicles which are small cells located in the skin. These follicles are located in the upper layer of the skin called the epidermis and push down into the second skin layer called the dermis as the wool fibers grow. Follicles can be classed as either primary or secondary follicles. Primary follicles produce three types of fiber: kemp, medullated fibers, and true wool fibers. On sheep, the hair part of the fleece is called kemp. Medullated fibers share nearly identical characteristics to hair, but lack crimp and elasticity. Kemp fibers are very coarse and shed out.^[2] Secondary follicles only produce true wool fibers. True wool has several qualities that distinguish it from hair or fur: it is crimped and elastic.^[3]

Crimp refers to the strong natural wave present in each wool fiber. Wool's crimp, and to a lesser degree scales, make it easier to spin the fleece by helping the individual fibers attach, so they stay together. Because of the crimp, wool fabrics have greater bulk than other textiles, and they hold air, which causes the fabric to retain heat. The amount of crimp corresponds to the fineness of the wool fibers. A fine wool like Merino may have up to 40 crimps per centimetre (100 crimps per inch), while coarser wool like karakul may have less than one (one or two crimps per inch). In contrast, hair has little if any scale and no crimp, and little ability to bind into yarn. The relative amounts of kemp to wool vary from breed to breed and make some fleeces more desirable for spinning, felting, or carding into batts for quilts or other insulating products.

The felting of wool occurs upon hammering or other mechanical agitation as the microscopic barbs on the surface of wool fibers hook together. Felting generally falls under two main areas, dry felting and wet felting. Wet felting occurs when water and a lubricant (especially an alkali such as soap) are applied to the wool which is then agitated until the fibers mix and bond together. Temperature shock while damp or wet accentuates the felting process. Some natural felting can occur on the animal's back.

Wool fibers readily absorb moisture, but are not hollow. Wool can absorb almost one-third of its own weight in water.^[4] Wool absorbs sound like many other fabrics.

Wool ignites at a higher temperature than cotton and some synthetic fibers. It has a lower rate of flame spread, a lower rate of heat release, a lower heat of combustion, and does not melt or drip;^[5] it forms a char that is insulating and self-extinguishing, and it contributes less to toxic gases and smoke than other flooring products when used in carpets.^[6] Wool carpets are specified for high safety environments, such as trains and aircraft. Wool is usually specified for garments for firefighters, soldiers, and others in occupations where they are exposed to the likelihood of fire.^[6]

Wool causes an allergic reaction in some people.^[7]

Sheep shearing is the process in which a worker (a shearer) cuts off the woollen fleece of a sheep. The quality of fleeces is determined by a technique known as wool classing, whereby a qualified person, called a wool classer, groups wools of similar grading together to maximize the return for the farmer or sheep owner. Wool-classers separate the wool into four main categories:

• Fleece (which makes up the vast bulk)
  • Best quality and highest value wool, often the longest and cleanest with the most uniform crimp
• Broken Fleece
  • High quality, but has broken into smaller pieces than the normal fleece
• Bellies
  • From the underside of the sheep, commonly stained and less dense resulting in lower value
• Locks
  • Shortest pieces of fleece often from a miscut by the shearer, lowest quality and value^{[citation needed]}

Wool straight off a sheep is known as "raw wool", "greasy wool"^[8] or "wool in the grease". This wool contains a high level of valuable lanolin, as well as the sheep's dead skin and sweat residue, and generally also contains pesticides and vegetable matter from the animal's environment. Before the wool can be used for commercial purposes, it must be scoured, a process of cleaning the greasy wool. Scouring may be as simple as a bath in warm water or as complicated as an industrial process using detergent and alkali in specialized equipment.^[9] In north west England, special potash pits were constructed to produce potash used in the manufacture of a soft soap for scouring locally produced white wool.

Vegetable matter in commercial wool is often removed by chemical carbonization.^[10] In less-processed wools, vegetable matter may be removed by hand and some of the lanolin left intact through the use of gentler detergents. This semigrease wool can be worked into yarn and knitted into particularly water-resistant mittens or sweaters, such as those of the Aran Island fishermen. Lanolin removed from wool is widely used in cosmetic products such as hand creams.

Raw wool has many impurities; vegetable matter, sand, dirt and yolk which is a mixture of suint (sweat), grease, urine stains and dung locks. The sheep's body yields many types of wool with differing strengths, thicknesses, length of staple and impurities. The raw wool (greasy) is processed into 'top'. 'Worsted top' requires strong straight and parallel fibres.

Common name	Part of sheep	Style of wool
Fine	Shoulder	Fine, uniform and very dense
Near	Sides	Fine, uniform and strong
Downrights	Neck	Short and irregular, lower quality
Choice	Back	Shorter staple, open and less strong
Abb	Haunches	Longer, stronger staple
Seconds	Belly	Short, tender, matted and dirty
Top-not	Head	Stiff, very coarse, rough and kempy
Brokes	Forelegs	Short, irregular and faulty
Cowtail	Hindlegs	Very strong, coarse and hairy
Britch	Tail	Very coarse, kempy and dirty
Source:[11]

The quality of wool is determined by its fiber diameter, crimp, yield, color, and staple strength. Fiber diameter is the single most important wool characteristic determining quality and price.

The finest and most valuable wool comes from Merino hoggets. Merino wool is typically 90–115 mm (3.5–4.5 in) in length and is very fine.^[12](between 12 and 24 microns). Because of this, Merinos are typically graded separately from other breeds:

Merinos

Diameter in microns	Name
< 15.5	Ultrafine Merino[8]
15.6–18.5	Superfine Merino
18.6–20	Fine Merino[8]
20.1–23	Medium Merino
> 23	Strong Merino[8]

The grades of wool may vary depending on the breed or purpose of the wool. Wool taken from sheep produced for meat, for instance, is typically coarser, and has fibers 40–150 mm (1.5–6 in) in length. Damage or breaks in the wool can occur if the sheep is stressed while it is growing its fleece, resulting in a thin spot where the fleece is likely to break^[13]. Different breeds have different average microns, and therefore value:

Breeds

Breeds	Diameter
Comeback	21–26 microns, white, 90–180 mm (3.5–7.1 in) long
Fine crossbred	27–31 microns, Corriedales, etc.
Medium crossbred	32–35 microns
Downs	23–34 microns, typically lacks luster and brightness. Examples, Aussiedown, Dorset Horn, Suffolk, etc.[13]
Coarse crossbred	>36 microns
Carpet wools	35–45 microns[8]

The finest Australian and New Zealand Merino wools are known as 1PP, which is the industry benchmark of excellence for Merino wool 16.9 microns and finer. This style represents the top level of fineness, character, color, and style as determined on the basis of a series of parameters in accordance with the original dictates of British wool as applied by the Australian Wool Exchange (AWEX) Council. Only a few dozen of the millions of bales auctioned every year can be classified and marked 1PP.^[14]

In the United States, three classifications of wool are named in the Wool Products Labeling Act of 1939.^[15] Wool is "the fiber from the fleece of the sheep or lamb or hair of the Angora or Cashmere goat (and may include the so-called specialty fibers from the hair of the camel, alpaca, llama, and vicuna) which has never been reclaimed from any woven or felted wool product".^[15] "Virgin wool" and "new wool" are also used to refer to such never used wool. There are two categories of recycled wool (also called reclaimed or shoddy wool). "Reprocessed wool" identifies "wool which has been woven or felted into a wool product and subsequently reduced to a fibrous state without having been used by the ultimate consumer".^[15] "Reused wool" refers to such wool that has been used by the ultimate consumer.^[15]

Wild sheep were more hairy than woolly. Although sheep were domesticated some 9,000 to 11,000 years ago, archaeological evidence from statuary found at sites in Iran suggests selection for woolly sheep may have begun around 6000 BC,^[16][17] with the earliest known woven wool garments having only been dated to two to three thousand years later.^[18] Woolly sheep were introduced into Europe from the Near East in the early part of the 4th millennium BC. The oldest known European wool textile, c. 1500 BC, was preserved in a Danish bog.^[19] Prior to the invention of shears—probably in the Iron Age — wool was plucked out by hand or with bronze combs. In Roman times, wool, linen, and leather clothed the European population; cotton from India was a curiosity of which only naturalists had heard, and silks, imported along the Silk Road from China, were extravagant luxury-goods. Pliny the Elder records in his Natural History that the reputation for producing the finest wool was enjoyed by Tarentum, where selective breeding had produced sheep with superior fleeces, but which required special care.

Economies of scale were instituted in the Cistercian houses, which had accumulated great tracts of land during the 12th and early 13th centuries, when land prices were low and labor still scarce. Raw wool was baled and shipped from North Sea ports to the textile cities of Flanders, notably Ypres and Ghent, where it was dyed and worked up as cloth.^{[citation needed]} As trade connections expanded in medieval Europe, the Champagne fairs revolved around the production of wool cloth in small centers such as Provins. The network developed by the annual fairs meant that the woolens of Provins might find their way to Naples, Sicily, Cyprus, Mallorca, Spain, and even Constantinople.^[20] The wool trade developed into serious undertaking, a generator of capital, and in the 13th century, the wool trade became the economic engine of the Low Countries and central Italy. ^[21]

A great deal of the value of woollen textiles was in the dyeing and finishing of the woven product. In each of the centers of the textile trade, the manufacturing process came to be subdivided into a collection of trades, overseen by an entrepreneur in a system called by the English the "putting-out" system, or "cottage industry", and the Verlagssystem by the Germans. ^{[citation needed]}In this system of producing wool cloth, once perpetuated in the production of Harris tweeds, the entrepreneur provides the raw materials and an advance, the remainder being paid upon delivery of the product. Written contracts bound the artisans to specified terms. Fernand Braudel traces the appearance of the system in the 13th-century economic boom, quoting a document of 1275. The system effectively bypassed the guilds' restrictions. In the same year, 1275, the English crown had imposed an export tax on wool called the "Great Custom".^[20]

During the 14th century, wool continued to play a central role in the English economy, and this can be seen in the fact that since then, the presiding officer of the House of Lords has sat on the "Woolsack", a chair stuffed with wool. At the time of the Black Death (1346-1353), English textile industries consumed about 10% of English wool production, and the English textile trade continued to grow during the 15th century, to the point where the export of wool was discouraged.^{[citation needed]}

By the end of the 14th century, Italy predominated in the European wool trade.^[20] Before the flowering of the Renaissance, the Medici and other great banking houses of Florence had built their wealth and banking system on their textile industry based on wool, overseen by the Arte della Lana, the wool guild: wool-textile interests guided Florentine policies. The Florentine wool guild, Arte della Lana, sent imported English wool to the San Martino convent for processing, while Italian wool from Abruzzo and Spanish merino wools were processed at Garbo workshops. ^{[citation needed]}Abruzzo wool had once been the most accessible for the Florentine guild, until improved relations with merchants in Iberia made merino wool more available. Francesco Datini, the "merchant of Prato", established in 1383 an Arte della Lana for that small Tuscan city. In the 15th century Pisa established a factory "which would export its cloths to the Crimea in exchange for Russian furs".^[22] At the same time, the sheepwalks of Castile were controlled by the Mesta union of sheep-owners. They shaped the landscape and the fortunes of the meseta that lies in the heart of the Iberian peninsula.

In the 16th century, a unified Spain allowed export of merino lambs only with royal permission. Towards the end of this century, Italian wool exports to the Levant had declined, and were eventually replaced by silk production. After the Restoration of 1660, fine English woolens began to compete with silks in the international market, partly aided by the Navigation Acts; in 1699, the English Crown forbade its American colonies to trade wool with anyone but England herself. Over the centuries, various British laws controlled the wool trade or required the use of wool even in burials. ^{[citation needed]}The smuggling of wool out of the country, known as owling, was at one time punishable by the cutting off of a hand. Later, the Industrial Revolution introduced mass-production technology into wool- and wool-cloth-manufacturing. Australia's colonial economy came to depend on sheep-raising, and the Australian wool trade eventually overtook that of the Germans by 1845, furnishing wool for Bradford, which developed as the heart of industrialized woolens production.^[23][20]

Due to decreasing demand for wool with increased use of synthetic fibers, wool production is much less than what it was in the past. The collapse in the price of wool began in late 1966 with a 40% drop; with occasional interruptions, the price has tended down. The result has been sharply reduced production and the movement of resources into production of other commodities, in the case of sheep growers, to production of meat.^[24][25][26]

Superwash wool (or washable wool) technology first appeared in the early 1970s, producing wool that has been specially treated so it is machine washable and may be tumble-dried. This wool is produced using an acid bath that removes the "scales" from the fiber, or by coating the fiber with a polymer that prevents the scales from attaching to each other and causing shrinkage. This process results in a fiber that holds longevity and durability better than synthetic materials, while retaining garment shape.^[27]

In December 2004, a bale of the then world's finest wool, averaging 11.8 microns, sold for AU$3,000 per kilogram at auction in Melbourne. This fleece wool tested with an average yield of 74.5%, 68 mm (2.7 in) long, and had 40 newtons per kilotex strength. The result was A$279,000 for the bale.^[28] In December 2006, the General Assembly of the United Nations proclaimed 2009 to be the International Year of Natural Fibres, so as to raise the profile of wool and of other natural fibers. In 2007, a new wool suit was developed and sold in Japan which can be washed in the shower, and which dries off ready to wear within hours with no ironing required. The suit, developed using Australian merino wool, enables woven products made from wool, such as suits, trousers, and skirts, to be cleaned using a domestic shower.^[29] The finest bale of wool ever auctioned was sold for a seasonal record of AU$2690 per kilo during June 2008. This bale was produced by the Hillcreston Pinehill Partnership and measured 11.6 microns, 72.1% yield, and had a 43 newtons per kilotex strength measurement. The bale realized $247,480 and was exported to India.^[30]

Global wool production is about 2 million tonnes (2.2 million short tons) per year, of which 60% goes into apparel. Wool comprises around 3% of the global textile market, but its value is higher owing to dyeing and other modifications of the material.^[1] China is the largest producer of Wool by weight, and Australia leads the market in the most Merino wool produced.^[31] New Zealand (2016) is the third-largest producer of wool, and the largest producer of crossbred wool. Breeds such as Lincoln, Romney, Drysdale, and Elliotdale produce coarser fibers, and wool from these sheep is usually used for making carpets.

In the United States, Texas, New Mexico, and Colorado have large commercial sheep flocks and their mainstay is the Rambouillet (or French Merino). Also, a thriving home-flock contingent of small-scale farmers raise small hobby flocks of specialty sheep for the hand-spinning market. These small-scale farmers offer a wide selection of fleece. Global woolclip (total amount of wool shorn) 2020^[32]

Rank	Country	%
1	China	19[a]
2	Australia	16
3	New Zealand	08
4	Turkey	04
5	United Kingdom	04
6	Morocco	03
7	Iran	03
8	Russia	03
9	South Africa	03
10	India	03

Animal rights groups have noted issues with the production of wool, such as mulesing.

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About 85% of wool sold in Australia is sold by open cry auction.^[33]

The British Wool Marketing Board operates a central marketing system for UK fleece wool with the aim of achieving the best possible net returns for farmers.

Less than half of New Zealand's wool is sold at auction, while around 45% of farmers sell wool directly to private buyers and end-users.^[34]

United States sheep producers market wool with private or cooperative wool warehouses, but wool pools are common in many states. In some cases, wool is pooled in a local market area, but sold through a wool warehouse. Wool offered with objective measurement test results is preferred. Imported apparel wool and carpet wool goes directly to central markets, where it is handled by the large merchants and manufacturers.^[35]

Most commonly, before being turned into clothing or other items, wool must first be processed into yarn. Different types of wool have different characteristics and can be turned into different types of yarn. For instance, shoddy or recycled wool is made by cutting or tearing apart existing wool fabric and respinning the resulting fibers.^[36] As this process makes the wool fibers shorter, the remanufactured fabric is inferior to the original. The recycled wool may be mixed with raw wool, wool noil, or another fiber such as cotton to increase the average fiber length. Such yarns are typically used as weft yarns with a cotton warp. This process was invented in the Heavy Woollen District of West Yorkshire and created a microeconomy in this area for many years.^[37]

Worsted is a strong, long-staple, combed wool yarn with a hard surface.^[36]

Woolen is a soft, short-staple, carded wool yarn typically used for knitting.^[36] In traditional weaving, woolen weft yarn (for softness and warmth) is frequently combined with a worsted warp yarn for strength on the loom.^[38]

After the yarn is made, it can be mixed with other materials and then woven or knit into the desired product.

Any wool finer than 25 microns can be used for garments, while coarser grades are used for outerwear or rugs. The finer the wool, the softer it is, while coarser grades are more durable and less prone to pilling. Like silk, the proteinaceous nature of wool requires special detergents when being cleaned because laundry detergents made to clean cellulose-based fabrics often contain stain-removing enzymes that digest protein.^[39][1]

Wool has a long history of being used for many different types of clothing. Many characteristics of wool allow for versatile fabric and clothing. For instance, wool has a high specific thermal resistance, so it impedes heat transfer in general. This effect has benefited desert peoples, as Bedouins and Tuaregs use wool clothes for insulation^{[citation needed]}. Furthermore, semigrease wool can be worked into yarn and knitted into particularly water-resistant mittens or sweaters, such as those of the Aran Island fishermen ^{[citation needed]}. Wool is commonly used today for many types of clothing, and initial studies of woollen underwear have found it prevented heat and sweat rashes because it more readily absorbs the moisture than other fibers.^[40]

In addition to clothing, wool has been used for blankets, suits, horse rugs, saddle cloths, carpeting, insulation and upholstery. Dyed wool can be used to create other forms of art such as wet and needle felting. Wool felt covers piano hammers, and it is used to absorb odors and noise in heavy machinery and stereo speakers. Ancient Greeks lined their helmets with felt, and Roman legionnaires used breastplates made of wool felt.

Wool as well as cotton has also been traditionally used for cloth diapers.^[41] Wool fiber exteriors are hydrophobic (repel water) and the interior of the wool fiber is hygroscopic (attracts water); this makes a wool garment suitable cover for a wet diaper by inhibiting wicking, so outer garments remain dry. Wool felted and treated with lanolin is water resistant, air permeable, and slightly antibacterial, so it resists the buildup of odor. Some modern cloth diapers use felted wool fabric for covers, and there are several modern commercial knitting patterns for wool diaper covers.

As an animal protein, wool can be used as a soil fertilizer, being a slow-release source of nitrogen.

Researchers at the Royal Melbourne Institute of Technology school of fashion and textiles have discovered a blend of wool and Kevlar, the synthetic fiber widely used in body armor, was lighter, cheaper and worked better in damp conditions than Kevlar alone. Kevlar, when used alone, loses about 20% of its effectiveness when wet, so required an expensive waterproofing process. Wool increased friction in a vest with 28–30 layers of fabric, to provide the same level of bullet resistance as 36 layers of Kevlar alone.^[42]

A buyer of Merino wool, Ermenegildo Zegna, has offered awards for Australian wool producers. In 1963, the first Ermenegildo Zegna Perpetual Trophy was presented in Tasmania for growers of "Superfine skirted Merino fleece". In 1980, a national award, the Ermenegildo Zegna Trophy for Extrafine Wool Production (later renamed the Ermenegildo Zegna Unprotected Wool Trophy), was launched. In 1998, an Ermenegildo Zegna Protected Wool Trophy was launched for fleece from sheep coated for around nine months of the year.

In 2002, the Ermenegildo Zegna Vellus Aureum Trophy was launched for wool that is 13.9 microns or finer. Wool from Australia, New Zealand, Argentina, and South Africa may enter, and a winner is named from each country.^[43] In April 2008, New Zealand won the Ermenegildo Zegna Vellus Aureum Trophy for the first time with a fleece that measured 10.8 microns. This contest awards the winning fleece weight with the same weight in gold as a prize, hence the name.

In 2010, an ultrafine, 10-micron fleece, from Windradeen, near Pyramul, New South Wales, won the Ermenegildo Zegna Vellus Aureum International Trophy.^[44]

Since 2000, Loro Piana has awarded a cup for the world's finest bale of wool that produces just enough fabric for 50 tailor-made suits. The prize is awarded to an Australian or New Zealand wool grower who produces the year's finest bale.^[45]

The New England Merino Field days which display local studs, wool, and sheep are held during January, in even numbered years around the Walcha, New South Wales district. The Annual Wool Fashion Awards, which showcase the use of Merino wool by fashion designers, are hosted by the city of Armidale, New South Wales, in March each year. This event encourages young and established fashion designers to display their talents. During each May, Armidale hosts the annual New England Wool Expo to display wool fashions, handicrafts, demonstrations, shearing competitions, yard dog trials, and more.^[1]

In July, the annual Australian Sheep and Wool Show is held in Bendigo, Victoria. This is the largest sheep and wool show in the world, with goats and alpacas, as well as woolcraft competitions and displays, fleece competitions, sheepdog trials, shearing, and wool handling. The largest competition in the world for objectively measured fleeces is the Australian Fleece Competition, which is held annually at Bendigo. In 2008, 475 entries came from all states of Australia, with first and second prizes going to the Northern Tablelands fleeces.^[46]

• Timeline of clothing and textiles technology

• "Story of Wool" . The New Student's Reference Work . 1914.
• "Wool" . New International Encyclopedia. 1905.