Wool conjures images of itchy holiday sweaters and scratchy blankets for many, but this natural material has so many qualities that go underappreciated. Today we’ll take a deeper dive into wool and its origins, properties, and best uses for the dapper man.
What is Wool?
Wool is a category of textile fibers derived from the coat of mainly sheep, but also goats, muskoxen, rabbits, camels, llamas, alpacas, vicunas, guanacos, and even cattle and pigs.
Wool’s Special Characteristics
While wool is grown to keep an animal insulated, it is not the same as hair or fur. Wool fibers are crimped and elastic, and they have scale, which in combination give wool it’s unique characteristics.
Crimp describes the waviness or texture of the wool, which corresponds to the fineness of the fiber. Merino wool can have as many as 100 crimps per inch. Scale is the roughness of the surface of the fiber. Hair, for example, has very little scale and no crimp, so it is nearly impossible to weave into a yarn since the smooth straightness of the hair doesn’t create grip.
Wool fibers have good scale, which helps the fibers attach to each other. Wool is also an elastic fiber, meaning that it resists distortion and has the ability to return to its original form.
Wool, interestingly, readily absorbs moisture while also being flame resistant. Wool is often used in contexts in which flame retardant properties are useful, such as the clothing and underlayers for firefighters.
Finally, wool contains lanolin, which is a natural wax that is produced in tandem with wool. It helps to “waterproof” sheep from the elements, preventing the wetness from reaching the skin of the animal.
For the purposes of this article, we’ll explore the history, finishing, buying, and care of sheep wool only. For more on cashmere, check out our Cashmere Explained Guide.
History of Wool
Sheep have been domesticated by humans since as early as 11,000BC, but evidence suggests that wool harvesting and weaving didn’t occur until 4000 or 3000 BC. Around 1900BC, Britain developed the ability to spin and weave. The earliest known preserved wool textile was discovered in a Danish bog, and it was dated to 1500BC.
The Romans wore primarily wool, linen, and leather for garments. In 50AD, they established a wool production center in what is now Winchester, UK. Despite the advances in wool finishing techniques, wool began to take on its greatest economic importance more than 10 centuries later in the Middle Ages. Annual wool fairs in cities across Europe made the wool the basis of much international trade, and wool was the primary export and economic driver of England and the kingdom of Castile.
In 1194, Richard the Lionhearted of England was being held prisoner by Henry, the Holy Roman Emporer, and part of his ransom was paid with 50,000 sacks of wool; this was the equivalent of an entire year’s worth of English wool production at the time.
Wars and invasions of neighboring countries caused talented weavers to relocate or be enslaved, creating new centers of wool production. Flemish weaver migrated to England in the 14th century to avoid a Spanish invasion, while Greek weavers were forcibly sent to Italy after the Norman conquest of Greece in the 12th century.
In the Rennaissance, the Medici family built their fortune (and empire) on the wool trade. Between the 15th and 18th centuries, the wool trade was so powerful that exporting sheep was punishable by death in Spain. Spain possessed the coveted Merino breed of sheep.
The value of wool was so powerful in Spain that it was said to have funded their extensive maritime exploration, including that of Christopher Columbus. In England, as much as two-thirds of exports were derived from wool during this period.
Other parts of the world also relied heavily on wool for the basis of their economy; England became a colonial powerhouse partly by building Australia’s economy on raising sheep and exporting wool. In 1797, the first Merino sheep arrived (the death penalty having been abolished two decades prior) and eventually were selectively bred to produce some of the finest wool in the world.
Wool was the world’s most important textile industry in terms of volume and value until the mid-20th century and the creation of synthetic materials. New synthetic fibers were cheaper, easier to wash, and felt softer on the skin, which led to big production declines.
Wool production across the world has declined by more than 50% since 1960, as land is increasingly allocated to more profitable uses such as beef and cotton growing. Even now, wool continues to lose ground to less expensive fibers in textiles and to increasing costs in the industry. Wool is predicted to become exclusive to the luxury good market unless radical changes occur to demand, production, and competition.
How is Wool Created
Wool is a very labor intensive fiber to produce. The process occurs over seven steps.
The process of making wool begins with shearing the sheep, which is typically done once a year in spring when the animals no longer need a heavy coat for insulation. The newly shorn wool is called a fleece, and even though there is some mechanization available, it is still predominantly done by hand. A single fleece can weigh 6-18 pounds.
Grading & Sorting
Grading and sorting break up a fleece into the various qualities of fibers, which come from different parts of the sheep. The best quality comes from the shoulders and sides of the sheep, which is then used for clothing.
Cleaning & Scouring
The wool must then be stripped of contaminants, which can equal 30-70% of the fleece by weight. The fibers are scoured with water, soap and alkaline ingredients.
Next, the wool is given a final cleaning and straightening by passing the fibers through a series of metal teeth. At this stage, the wool is separated into two types, worsted, and woolen. Wool for worsted yarn is stripped of the shorter fibers and the long fibers are aligned. Wool intended for woolen yarn goes directly to the spinning stage.
The carded wool is then turned into thread by spinning it into a single strand of yarn. Multiple yarns are then spun together with other yarns (referred to as ply). Since wool has an excellent scale, it is easy to spin it into yarn relative to other fibers.
The threads are then woven into a fabric, typically in the form of a plain or a twill weave. Woolen yarns are woven into a plain weave, which results in a looser construction and a softly napped surface. Worsted yarns are woven in a twill weave, resulting in a smooth finish that is prized for its durability relative to the woolen yarn. Suit fabrics are a good example of the intended use for worsted wool twill weave.
The process of finishing adds the final desired characteristics to the woven wool. Wool can be shrink-proofed, fulled and crabbed to interlock and set the fibers, and dyed to the desired color.
The Best Quality Wool
More than 500 breeds of sheep around the world produce approximately 1.2 million kilograms of raw wool each year. The wool can be classified based on the diameter of the individual fibers, in units of microns.
- Fine wool <= 24.5 microns
- Medium wool 24.6-32.5 microns
- Coarse wool >32.5 microns
Fine wool fibers are used for clothing, while the thicker fibers are used for rugs and interior textiles. The stereotypical “itchy” wool sweater occurs when the retailer uses a larger micron diameter wool, as the rough ends of these fibers scratch the skin.
Woolens and worsteds are often categorized by a few origin-based terms:
Merino is a specific breed of sheep that has fine fibers. It’s the softest wool on the market, though not all merino wool is created equal. Standard merino wool is about 23 microns; fine merino around 18 microns; superfine is 16, and ultra-fine is less than 15.5 microns. The long length of the Merino fiber also makes it resist pilling better than shorter fiber wool.
Lambswool comes from the first shearing of a sheep at around age 7 months, when the fibers are particularly soft and elastic. It’s the rarer, higher-quality version of regular wool.
Shetland Wool comes from, you guessed it, a breed of sheep living on the Shetland islands. This wool is around 23 microns, making it much rougher than lambswool and Merino wool. This wool is great for heavy, warm sweaters you plan to layer over shirts.
This type of wool will offer you little information besides the fact that it comes from a woolly animal. It is most likely sheep, but it’s the lower quality, rougher cousin of lambswool and merino.
Manufacturers often blend wool with other fibers to increase softness, make it easier to wash, or to cut costs while retaining a higher price.
Environmental Consequences of Wool
Like all natural materials, wool has an impact on the environment that you may want to consider before buying it. Wool comes from livestock, which has environmental issues such as water pollution, land overuse, and wildlife impacts. Sheep need ample grazing lands, and they tend to over-graze land in a way that pickier livestock (such as cows) do not. Like cows, sheep emit methane, which is a greenhouse gas that negatively impacts climate change. Sheep are dipped in insecticide baths to prevent infestations, which can linger in wool. Wool production requires a great deal of water, dyes, and chemicals. Some also consider the process of shearing the sheep to be cruel.
On the positive side, wool is a renewable natural material. Wool is a biodegradable material with useful environmental applications. As it degrades, wool slowly emits the nutrient nitrogen and retains water well, making it an effective substitute for other artificial turf products and some fertilizers. In the same way, wool can be used to help prevent erosion.
What Do the Super Numbers Mean?
When you buy a suit made of wool today, chances are super number like Super 100’s, 120’s or 150’s will be advertised but what is that supposed to mean?
In short, not much as it is not a legally regulated term and many weavers use their own scale. Basically, the higher the number, the finer the yarn diameter used in the fabric. Reputable weavers abide by the Fabric Labelling Code of Practice by the International Wool Textile Organization (IWTO) and you can learn all you need to know about super numbers here.
How to Buy Wool
Buying wool can be a frustrating experience because so few retailers list the details of materials beyond the “100% wool” tag. The more information the retailer provides, the more transparent they are willing to be about the quality of their wool. If quality is important to you, look for more rather than less information on the product description and ask sales staff for more details.
For the purposes of comfort, the finer the wool fiber, the softer it is on the skin. That being said, wool isn’t always worn directly against the skin, and it’s advisable to avoid doing so to limit the frequency of cleaning.
For woolens such as sweaters and vests, buy the softest quality you can afford. Merino is the most expensive, followed by lambswool. That being said, if you are planning to layer these garments over others, 100% wool will still be comfortable for you and your wallet.
Sources for High-Quality Wool
The market for wool products is ever-changing, so use your newfound knowledge of wool to keep an eye out for great wool products. For some reliable sources for wool products, check out these manufacturers below.
Shetland Wool Sweaters and Blankets: Pendleton
Affordable, simple wardrobe staples in lambswool and merino: Uniqlo
For a range of merino and lambswool basics, WoolOvers
For a range of wool pocket squares and reversible Silk/Merino scarves, check out Fort Belvedere.
Merino fisherman and cardigan sweaters, Blarney Woolen Mills
For more, check out our extensive Sweater Guide.
How to Wash Wool
Wool does not have a reputation as being easy to wash and care for. It can shrink, pill, and become distorted if cared for improperly, and it is true that the less wool is handled, the better it will last.
The main challenge with wool lies in one of it’s prized characteristics – its scale. The grip of the fibers makes it excellent for spinning, but this characteristic also makes it difficult to maintain in the fabric’s original shape. Whenever the fabric is rubbed or agitated, the fibers grip and interlock with their neighbors, tightening or pilling the fabric. Wool also readily soaks up water, which can stretch and distort the fabric with the excess weight of the water in the material.
Many wool sweaters indicate that they should be dry cleaned, but this is not a good solution. Even though it claims to be “dry”, dry cleaning uses a commercial-sized washing machine and a bath of chemicals in place of water and detergent. For a thorough look at dry cleaning, check out our article.
Wool can be safely cared for at home without the need for dry cleaning. First, minimize the need to wash wool sweaters by wearing them carefully. Wear an undershirt with them to avoid contact with sweat and dirt, and fold them rather than hanging them.
For a sweater that does need washing, begin by rolling it tightly and stuffing it into a mesh laundry bag – it is crucial that there shouldn’t be any extra room in the bag. This prevents the sweater from rubbing up against itself or other clothes. Wash it on the shortest, gentlest cycle in your washer (delicate or handwash) with a small amount of mild detergent and warm water. Yes, warm water! Cold water does not activate soap, which can leave soap residue behind. Furthermore, heat increases the viscosity of water, allowing it to flow better in and out of the fabric.
To finish, never dry wool in the machine – carefully reshape it if needed and allow it to dry flat.
Wool may very well become a fabric only used in luxury clothing, but it has some remarkable properties that make it worth the expense. What wool pieces do you own?