What are the types of wool?

The season of sweaters is almost upon us and we thought we would take it upon ourselves to break down the various styles of wool and animal fibres that make them up for you.

This guide aims to cover the most commonly seen names on the inside labels of your wool clothes, including Lambswool, Merino, Cashmere, Angora, Mohair, and Alpaca, to help you distinguish your wools from your hair and to give you an overview of the various properties and pros and cons associated with each.

We humans have used wool and hair in clothing since at least 6000BCE, when ancient Iranians started domesticating wool sheep, to keep our bodies warm. What started out at the very top of the food chain as a simple survival instinct for us hairless mammals has since developed in the name of fashion into an industry of farming domesticated animals. True, for practical purposes, many people still rely on garments, but many also have the luxury of being able to select their ideal choice of knitwear by hand, whether it is light or heavy, natural or dyed, merino or cashmere.

It can be hard for many to differentiate between the various types of wool and hair, apart from the soft and luxurious feeling most often associated with the common cashmere. While both the farming processes and the general properties of wool and hair have many similarities, they are generally separated by what animal they are sourced from. Wool comes from sheep (Merino, Lincoln, Dorset, etc.), while fur comes from other species, such as goats (cashmere, mohair), alpacas (alpaca), and rabbits (angora).

What’s fur, then?

Wool refers to the complete fleece on the sheep’s outer skin, while fur is generally divided into two types: the topcoat (also known as ‘guard hair’) and the undercoat. Usually used for rain cover, the guard fur is on the outside of the animal; it is thicker and coarser than the undercoat whose fine hair is used to keep the animal warm.

The undercoat is smooth, highly prized and usually favourable for knitwear use, but both are often mixed into the same finished yarn (e.g. in mohair). In general, wool fibres are shorter, thicker and have more pronounced scales, while hair normally has longer, thinner and less pronounced scales.

The Wool Advantages

Robert Lim, our columnist, recently proclaimed his love for wool, but let us remind you why. Wool and hair have many common general properties, making them attractive for use in a range of clothing:

They are usually robust, water-repellent, and flame retardant.
Owing to their moisture wicking properties and ability to trap air, they provide strong insulation.
They take dye exceptionally well and both alpaca sheep’s wool and hair provide a wide variety of natural colours that do not need extra dyeing.

In contrast to using plant fibres, they usually have a limited environmental impact.
On top of that, it’s easy to renew and recycle wool and hair.
And although keeping animals reared requires both food, energy, water, and medication, the environmental impact naturally differs from factory to factory, with some organic processing of wool and hair and free of pesticides and chemicals.

Many of the attractive properties associated with wool and hair are derived from a natural protein called keratin, found in the fibres of mammalian hair and skin. The bilateral keratin centre induces twisting and bending of the fibres, giving wool its natural crimp and resilience. Another advantageous property of keratin is its flame-resistance, which makes wool and hair fibres self-extinguishable until they are no longer directly exposed to a flame, unlike with plant fibres.

One downside, however, is that when exposed to water, wool and hair get weaker, with wool losing around a quarter of its strength when wet. Another downside of wool and hair (and other natural fibres) is their propensity to become food for moths, an issue that synthetics do not share. That being said, it is arguably unmatched by any man-made fibre known today because of the beneficial properties of wool and hair.

How to Assess Wool Quality

Aside from different kinds of animals and breeds, the consistency of wool and hair is decided by many factors. Both wool and hair are measured by their properties, such as strength, staple length (fibre length) and fineness (micron diameter), as well as consistency and defects.

Generally, when one end remains uncut, the first shear from any animal is the softest and considered the most important. The staples are spun into various forms of yarn after shearing, usually separated as carded (woollen) and combed (worsted). In order to reduce costs or to impart other qualities, wool and hair are also combined with other fibres (natural or man-made), such as in a sweater to enhance elasticity, longevity and to help it retain its shape. When the individual characteristics are lost to the mixture, it is referred to as a ‘intimate blend’ as a jumper from an intimate blend with 20% nylon is likely to lack some of the properties of a 100% woollen jumper, such as warmth, moisture wicking, etc.

In wool processing, there are several different breeds of sheep used and their fibres vary from approximately 10-50 microns in diameter and 1.5-4.5 inches in staple length. The various breeds come in different shapes and sizes and live in different countries and climates that affect the quality of their fleece along with age, health, and diet.

Wool has a low tenacity (the ultimate force it takes to split the fibre) that worsens when wet, but before splitting, wool can stretch up to a quarter of its size. In general, wool fibres are sturdy and are able to bend a thousand times more than fibres produced by man. The pronounced scales in the wool fibres make woollen fabrics more vulnerable to tangling and thus important to nonwovens such as felt, but the propensity to shrinkage is also increased.

The Most Popular Wool Types

Now that we know all about wool and hair’s general properties, let’s break down some of the most common styles.

  1. Lambswool

The first shearing of sheep usually provides the finest and softest wool, as with most wool and hair. This is known as Lambswool and is generally shorn from lambs younger than 7 months of age. Depending on breed, health factors, etc, sheep yield anywhere from one to thirteen kilos annually. Some breeds produce a highly durable fleece that is hard to wear and therefore good for tapestries, rugs, and upholstery, whereas other breeds produce a fine fleece with a softer hand feel that is therefore common in clothing.

  1. Merino’s

Merino, which originates from the Merino sheep, is the finest and softest sheep wool. It is the most common sheep breed used for clothing and provides the most luxurious wool, renowned for its fine staples with a diameter of about 20-25 microns (superfine merino may sometimes be down to 17 microns) and a soft hand feel. Thanks to its long staples at about 4.5 inches, it has excellent drape. The sheep originated from Spain, but about 80% of all Merino now comes from Australia.

Merino requires scouring, like other sheep’s wools, before being spun to yarn, which is an energy-and time-consuming process involving washing and rinsing the wool. The fatty grease lanolin, which is a by-product used in cosmetics, gets rid of this, but it ensures that just about half of the initial fleece can be used to produce a dress. As the fur of goats, alpacas, or rabbits does not contain lanolin, the scouring process is special to wool. Yet, merino processing is still not as inefficient as cashmere production.

Merino Wool Sweater by Loop & Weft at Okayama Denim.

  1. Kashmir

Cashmere is extracted from the cashmere goat’s undercoat, which makes up just around one-quarter of the total fleece. Known for its luxurious soft hand feel, cashmere, similar to superfine merino, is exceptionally fine with a diameter of about 18 microns. The finest cashmere originates from the undercoat neck area that has to be combed for one or two weeks. Usually, one goat produces 150 grammes of cashmere a year, which is a small production compared to the remaining fibres, explaining the high price of cashmere.

It has equal durability to sheep’s wool, but it is usually more fragile than wool because of the fine cashmere fibres. The nap is usually lifted on the wool to maximise the softness when cashmere is finished into garments. Many modern napping devices use metal tines (e.g. lambswool), but more historically, dried teasel pods have been used for soft and fragile materials such as cashmere and are still considered superior.

  1. Mohair

Mohair is derived from the goat Angora (sometimes confused with the angora yarn that comes from the angora rabbit). Compared to the cashmere goat, it has a larger undercoat, but the guard hairs from the topcoat are mostly mixed with the hairs from the undercoat, as with cashmere. With the slightly stiff short hair evident in the final product, this gives mohair its distinct, frizzy appearance.

Mohair fibres are around 25-40 microns, which is similar to wool, but due to its long 4-6 inch staples, it is considered to be thicker, smoother, and more durable than wool. The finest fibres of mohair come from the first three Angora goat shears. It has less pronounced scales than wool, which decreases tangling/shrinkage and reduces the dirt it gathers as well. Angora goats are farmed on a much smaller scale, similar to sheep, which may be why mohair is slightly more costly than wool. In a year that is slightly more than the cashmere goat, one Angora goat yields about 3-5 kilos of mohair, but its end product is not as soft and exclusive.

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