Everything you need to know about wool
Wool is an exceptional natural fiber—an excellent thermal insulator that also allows water vapor to pass through, which is why we say it “breathes.” When a garment is made from high-quality wool fabric spun from long-staple yarn, it quickly regains its shape after wearing and hanging, often without the need for ironing.
What Does “Super 100’s” Mean on a Label?
On the inside of men’s suits made from wool fabrics, you’ll often see markings such as SUPER 100’s, SUPER 200’s, and so on. The letter “S” or the word “SUPER” means the fabric is made from 100% pure wool, while the number refers to the fineness of the fibers, measured by their diameter. Very fine, long, lightweight fibers—anything above SUPER 180’s—allow for an extraordinary drape and comfort. However, these fabrics are also more delicate, wrinkle more easily, and are less suited for frequent wear. Tailors often describe them as “alive” because of their fluidity and the challenge they present in cutting.
Merino Wool
The best-known type of wool is sheep’s wool, but its quality varies greatly. The finest merino wool comes from sheep in Australia and New Zealand. Quality depends on the diameter and length of the fibers: the finest fibers measure around 19 microns (SUPER 100’s), while coarser wool can reach up to 40 microns. Fineness, fiber length, natural curl, and color all influence the fabric’s value, softness, resilience, and resistance to creasing.
Special Varieties of Wool
Shetland wool comes from purebred Shetland sheep, mostly raised in organic farms on Scotland’s Shetland Islands. It is soft, durable, and warm. Tasmanian merino, sourced from Tasmania’s sheep, is renowned for its supreme quality, with the finest grades used for formalwear like tailcoats and tuxedos. Natural stretch wool achieves elasticity without added synthetics, relying on wool’s inherent spring and special weave techniques—ideal for men’s business suits. Cool wool is a lightweight, smooth worsted wool with a cool touch, perfect for summer suits.
The Woolmark Standard
The Woolmark logo is an international certification for products made from pure new wool. Overseen by The Woolmark Company, it guarantees both the quality of the raw fiber and the manufacturing process.
Other Animal Fibers in the Wool Family
Camel hair, taken by combing the neck area, is used in blends with wool for warm winter coats and blazers, often with added silk for a subtle sheen. Cashmere comes from the downy undercoat of Asian cashmere goats and is commonly blended with wool for jackets, scarves, and sweaters. Mohair, from the Angora goat, is silky and lustrous, usually mixed with sheep’s wool for blazers. Alpaca, llama, guanaco, and vicuña fibers are luxuriously soft yet strong, often blended with wool, cotton, or silk. Cashgora, a hybrid of cashmere and Angora goat hair, makes superb coats and knitwear.
Why Wool Stands Out
Wool fibers have unique qualities that make them beloved in the textile industry. They are naturally elastic, returning to shape after stretching; they provide superb insulation by trapping air between fibers; they can absorb up to 30% of their weight in moisture without feeling wet, regulating body temperature and preventing clamminess. Wool breathes, allowing air and moisture to circulate, which prevents overheating. It is antistatic, so it doesn’t cling or attract much dust, and it is biodegradable, breaking down naturally to reduce environmental impact.
With the right care, wool garments can last for many years while retaining their beauty and functionality. (Read more about caring for wool here.)