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Merino Wool: History, Benefits, Facts and Uses

POSTED ON September 5, 2020 BY Ralph S.

What is Merino Wool?

Merino Wool is the wool extracted from the breeds of sheep called Merino. It is famous the world over for its unique and natural properties. What differentiates it from other types of wool are its finer, softer and luxuries fibers.  Softness, breathability and shine are some other characteristics of Merino wool that differentiate it from the rest of the pack. Wool is durable, warm and water-repellent, but Merino wool takes it to another level and has a unique feel to it.

Wool remained the primary material for clothing in the middle ages and is still one of the most popular. It’s unique and eco-friendly properties not only make it suitable for clothing, but also for many other purposes both functional and decorative. Researchers are still developing new applications for this renewable and biodegradable material.

Merino wool is covered by Lanolin, which is a natural waxy material that is water-repellent and protects sheep from hard climate and infections. It also makes the garment soft to touch, stays elastic and resists growth of bacteria, mold and mildew.

Today’s merino wool is the result of over 3,000 years of continuous refinement and selective breeding. Merino wool has come a long way from being itchy, thick and coarse into a smooth, luxuriously light and functional fabric.

wool yarn

A Short History of Merino Wool

The history of Merino wool can be traced back to the 12th century. Although its origins still remain a subject of debate, Morocco and Spain are believed to be the regions where it first originated in flocks. The material was closely guarded in the old times and its export was punishable by death in Spain until around the 18th century. Australia, the top producer of the wool, had banned the export of Merino sheep until 1986.

Genetic studies suggest that merino sheep were developed by cross-breeding churro ewes with other breeds, including during the Roman times with Italian rams, in the mediaeval period with northern African rams and in the 15th century with English rams.

Selective cross-breeding of Spanish ewes and imported rams was carried out in the 12th-13th centuries, which played a pivotal role in Spain’s economic development in the centuries to come. Spain’s monopoly on Merino wool remained for quite some time until sheep breeds were further refined in the late 18th century in Australia and New Zealand, which is what we now refer to as ‘modern’ merino wool.

Merino Wool Qualities: It’s All About the Microns

The fineness of merino wool is measured in microns, which refers to fiber’s circumference in a strand of raw-wool. One micron is 1/1000 of a millimeter. A human hair on average is around 45 microns and for reference medium grade merino wool has around 20 microns diameter. g/m2 (grams per square meter) is another measurement to define wool coarseness and the lower the number, the lighter, softer and finer the wool.

merino wool fibre and human hair comparison

The diameter of Merino wool ranges from 11.5-24 microns (mostly 16-24) and it is graded according to this diameter, which is microscopic. Selective breeding is the key to such ultra-fine wool. Here are different types or grades of merino wool according to the level of fineness (diameter is in microns, the micron range can vary from one region to another):

Strong                                       22.6 to < 24

Medium                                   20.6-22.5

Fine-medium                         19.6-20.5

Fine or extra-fine                 18.6-19.5

Superfine                                17.6-18.5

Ultrafine                                  16.1-17.5

Extra Ultrafine                       16.0 or lower (used for blending with fibers such as cashmere and silk)

structure of a merino wool fibre

Global Production and Largest Producers of Merino Wool

Australia is the biggest player in merino wool production and produces a significant portion of the total wool used in apparel, while New Zealand, China and the USA are the next largest producers respectively. Australia produces roughly 80 percent of the total merino wool used in apparel (Source: New Merino Australia).

Many textile companies use the term merino wool for their products, but it does not necessarily mean that the fiber is 100 percent merino wool harvested from a sheep that was bred specifically for wool. Although technically any wool extracted from a merino sheep can be called merino wool, not all types of wool extracted from these sheep are suitable for clothing.

This is especially relevant to the clothing items that you wear right next to your skin. For example, merino sheep that have been bred for meat don’t usually produce fleece with a staple that is fine enough for clothing items.

The global annual production of all types of wool is estimated to be around 2 million tonnes with almost 60% of it used in apparel. Since Australia is the biggest producer, our focus will be on Australian Merino sheep.

Types of Merino Sheep

Australian merino does not refer to a particular breed of merino. It refers to a number of strains of different sheep. The four types of Australian merino sheep, which are the ancestors of the vast majority of other sheep are as follows (Source: Australian Association of Stud Merino Breeders):

Peppin Merino

Around 70% of all wool coming from Australia is extracted from the descendants of Peppin Merino Sheep. With a diameter of 20-23 microns, it has a medium finesses level. It’s so common in Australia that people there usually think of merino wool as either Peppin merino or non-peppin merino.

Also known as the Wanganella stud, Peepin brothers established it in 1861, possibly a cross-breed between Spanish and French sheep. Peppin sheep thrive in drier regions and have fleece that is heavy with greater wool grease content. Today’s Peppin sheep can produce up to 18 Kg wool each year (with about 10kg on average).

South Australian Merino

The South Australian Merino sheep produce heavier, longer and thicker wool than other types of merino sheep. That’s mainly because they have been bred this way in order to thrive in the arid pastoral conditions of the South and to provide greater economic return. It’s also the largest Australian merino sheep. The wool is the thickest and the strongest and loaded with natural grease. These sheep are also found in New South Wales, Queensland and Western Australia.

Spanish Merino

Closest to the original Spanish Merino Sheep, these Australian sheep are outnumbered by a large margin by other types. They are quite similar to Peppin Merino sheep and produce wool of a similar quality.  These are also cross bred with Saxon Merino for extra-fine wool and a better wool coverage.

Saxon Merino

Although the smallest, Saxon merino sheep produce the finest merino wool and are exclusive to southern Australia in the higher rainfall county. However, compared to Peppin Merino sheep that can produce up to 18 KG wool/year, these only produce 3-6 kilos/sheep/year respectively, but that’s extra-fine wool and not some ordinary wool. The white, bright and soft wool with a diameter of 14-17.5 microns is more expensive and used in luxury clothing products.

The Poll Merino

Established in 1934, these are merino sheep without horns and scattered throughout Australia within different bloodlines of the aforementioned types. The fineness of the wool depends on the bloodline and can vary from one breed to another. Some studs produce medium strong, while others can produce fine wool.

merino sheep in snow during winter

Key Qualities and Characteristics of Merino Sheep

Merino sheep are forager and can quickly adapt to almost any environment. These sheep are predominantly bred for their wool and are smaller than those bred specifically for meat. Sheep are also bred for both meat and wool such as the South African Meat Merino, German Merinofleischschaf and the American Rambouillet, while maintaining a balance between the production and quality of meat and wool.

Since Merino sheep have been bred and domesticated in a certain way, they cannot survive well if not sheared at least once a year. Their wool keeps growing and if not sheared. The excess wool can overburden them, causing heat stress and making it very difficult for them to move and in severe cases survive. In some cases, not shearing these sheep can even lead to blindness.

merino sheep shearing

Softness and fineness is what defines merino wool and differentiates it from other types of wool. The staples can range from 65 to 100mm. For example, on average a Saxon Merino sheep produces from 3 to 6 kg / 6 – 12 lbs. of wool per year, while a Peppin Merino has a much higher production of up to 18 KGs.

Benefits of Merino Wool

All types of wool have excellent insulating, temperature-regulating and anti-bacterial properties that make them an excellent choice for clothing items such as wool hiking socks. Wool retains heat while being breathable and that’s why it’s used a lot in clothing items such as knitwear, coats and socks. Wool also blends well with other fabrics such as synthetic materials like nylon and polyester and natural materials such as cashmere.

For example, merino hiking socks are usually made using a blend of merino wool, synthetic fibers and spandex. Water-resistance is another property that makes wool such a good material for clothing items. Each fiber of wool can hold up to 30 percent of its own weight in moisture (without feeling wet). It quickly wicks the moisture away from the skin, helping the wearer remain dry.

The anti-microbial properties of merino wool mean they are odor-resistant, making them particularly suitable for people who usually suffer from allergic reactions. This is one of the reasons why merino wool hiking socks are so popular in the backpacking community. Merino wool is regarded highly when it comes to children’s clothing because it is durable, hard wearing and has natural elasticity. Here is a summary of why you should consider merino wool and its key benefits:

  • Temperature regulating, naturally breathable
  • Keeps you warm in winters and absorbs moisture when it’s hot
  • Odor-resistant, also referred to as the ‘deodorant fiber’, does not smell quickly and makes you feel fresh
  • No need to wash every time you wear it
  • Dries quickly, which is a great thing on long hikes
  • Elastic, wrinkle-resistant, so no ironing needed when traveling/hiking/backpacking
  • Prevents stains from getting absorbed
  • Merino wool does not itch like regular wool
  • Durable and 6-times stronger than cotton
  • Non-allergenic and reduces eczema symptoms
  • UV resistant, because sheep have to stay in sunlight all day long, keeps you save from UV radiation
  • Biodegradable, decomposes naturally and gives nutrients back to the Earth where they came from
  • Requires washing less frequently because of high strain-resistance
  • Can be worn for longer periods of time, so hikers can take fewer clothing items i.e. less weight

merino wool sheep

Common Applications of Wool

Compared to ordinary wool, merino wool is finer, softer and used in luxurious clothing items such as merino wool hiking socks. Merino wool does not irritate or itch the skin like other materials, absorbs moisture efficiently and dries quickly. These traits make it an ideal material for sportswear and high-end clothing items, but there are plenty of other uses too and some are quite surprising. Different uses of wool include:

  • Clothing and apparel such as merino socks and jumpers
  • Lightweight summer clothing
  • Wool insulated outerwear such as a dress coat, and puffer jacket (fillings)
  • Activewear
  • Firefighting uniforms
  • In the padding of carpets
  • Soft furnishings and furniture, household upholstery, covers and stuffing, blinds, lampshades, cushions, curtains, wallpapers etc.
  • Bedding, wool blankets, duvets (better sleep due to effective temperature-regulating and hypoallergenic properties)
  • As an insulator in walls
  • In mulch pads as an organic alternative, in Italy researchers are even looking into turning wool (that is not suitable for processing) into fertilizer
  • Lanolin, a by-product of wool is used for different things such as adhesives, auto lubrication, shampoos and other cosmetics. No by-product of wool goes to waste
  • Also used as a blend with seaweed to reinforce bricks in an environmentally friendly way
  • Packaging boxes are also insulated using wool
  • Sometimes used in soaking up large-scale oil spills
  • Used in pianos to soften the impact of hammers

Merino Wool vs. Other Materials and Blends

Merino wool can be blended with a variety of other materials both natural and synthetic, including silk, cashmere, nylon and polyester. Common clothing items made using blends of merino wool include socks, knitwear and base layers. Here is a quick summary of how merino compares to other materials:

Merino Wool

(Harvested from sheep bred specifically for wool)


Strong and durable, biodegradable (takes only 6-months to decompose), excellent moisture-wicking and temperature-wicking properties, highly hydrophilic, can absorb a lot of moisture without feeling wet, antibacterial properties, cheaper than Cashmere, flame-resistant, does not wrinkle, excellent insulation, naturally anti-static and stain-resistant (less frequent cleaning)


More expensive than other materials, people with ultra-sensitive skin may feel a little itchy, takes longer to dry than polyester (up to 40% longer), not durable enough on its own for most uses in clothing (100% merino wool can develop holes)


(From Cashmere goats, harvested by combing instead of shearing, very small output of around 120 grams per goat, 19 microns or less in diameter)


Lightweight, good warmth-to-weight ratio, up to 8 times warmer than merino, softer, luxurious


Expensive, not as durable as merino wool, harder to care for, can lead to overheating because of higher insulation


(Younger sheep, first shearing usually after 7 months of the first coat, diameter can vary considerably)


Softer and finer, other properties similar to merino wool


The diameter (microns) can be inconsistent because lambswool can come from any type of sheep, so fineness cannot be guaranteed and varies from one breed to another



Affordable, easier to care for


Not good at wicking moisture & sweat, poor warmth-weight ratio, not recommended for hiking and backpacking

Synthetic materials


Cheaper, lighter, high-quality synthetic materials are more durable and dry very quickly


Not as comfortable as merino wool, develops odor very fast, not as good at wicking moisture, by-product of oil, not biodegradable, not flame-resistant like merino wool

Wool Blends


Offer the benefits of both merino wool and blended materials, such as increased durability, faster-drying times and anti-bacterial/anti-odor properties at the same time.


Might not be as comfortable, odor-repellent or temperature-regulating/insulating as 100% merino wool

Some Fun Facts about Sheep and Wool

Chris the Sheep became popular for being the sheep with the heaviest fleece in the world and died in Australia of old age (around 10 years). It carried 6-years-worth of wool and was spotted in 2015 in the wild. A shearer gave her a life-saving haircut by removing 41.1 kg/ 88 lbs. fleece, which is considered an unofficial world record

  • World’s most expensive sheep, a texel lamb named “Double Diamond”, was sold for $490,000 in 2020, breaking the previous record of $307,000 from 2009.
  • Australia produces a massive 282,000-tonnes of wool each year
  • Australia’s Poll Merino breed has no horns
  • There exist more than 900 breeds of sheep around the world with Merino being the most popular
  • The fleece never stops growing on a merino sheep and has to be sheared at least once every year. Failing to do so can have serious consequences for the sheep and can lead to overheating, inability to move or even blindness
  • Merino sheep wool has built-in UV protection, preventing sheep from getting sunburnt
  • Compared to regular wool, merino wool is a lot more comfortable and does not irritate the skin
  • Merino wool contains lanolin, a chemical that has antibacterial and water-repelling properties. No surprise it’s being used in thermal underwear.
  • Sheep are not dumb, they can recognize and remember as many as 50 different sheep faces as well as human faces
  • Thanks to the rectangular and large pupils, sheep have very good peripheral vision and can see almost 360-degrees, even behind without having to turn their heads
  • Unlike other materials, wool retains its warming properties even when wet, which works great for backpackers and hikers
  • Compared to cotton that can break after around 3,000 bends, wool can easily last 20,000 bends

herd of sheep on grass field

Disadvantages of Merino Wool

Many people swear by merino wool and would wear nothing else if possible for them. However, merino wool is not as super soft as textile companies might want you to believe. Sure, it’s not itchy like regular wool (in fact a lot better), but it’s also not silk. It’s also not as durable as some synthetic materials and it can shrink if exposed to too much heat.

Merino wool garments are about practicality, so they are usually plain and might look ‘unstylish’ to some. Merino lacks the degree of versatility other fabrics have, so fashion designers have to try hard to turn it into something stylish and eye-catching.

Use of Merino Wool in Hiking/Backpacking Apparel and Sportswear

Merino wool is used in a variety of backpacking and sportswear items because of its unique characteristics as discussed before, especially baselayers and other next-to-skin layers such as socks and underwear. That’s because merino wool helps regulate body temperature, wicks moisture and dries relatively quickly. Silverlight hiking socks are one of the best merino wool hiking socks that provide an odor-free hiking and backpacking experience while ticking all the boxes when it comes to comfort.

Silverlight Socks Medium Crew Black




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Being a high performance fiber, merino wool is also used in activewear products and even firefighting uniforms (wool has a flame retardancy of up to 600°C/1112°F). It does not stick to skin, shrink and melt in high temperatures and does not produce toxic odors. These characteristics along with the comfort factor make merino wool a great material for hiking and backpacking gear as well as sportswear, including wool hiking socks, long sleeves and pants.

Tips for Taking Care of Merino Wool Products

Merino is naturally stain and odor resistant, so you don’t need to wash it as frequently as clothing items made of other materials. It’s a common perception that it’s hard to take care of merino wool, but it’s not that difficult if you know some basic maintenance guidelines including:

  • Always follow the garment-specific machine guidelines
  • Machine wash separately on low heat, use cold cycle or wool-specific option if available
  • Wash separately or with similar colors, washing with harder garments like denim helps prevent pilling
  • Wash inside out to prevent bobbling
  • Use a mild detergent, when using a powder detergent, first dissolve it in some water to prevent settling of large flecks on the fabric
  • Avoid using fabric softeners, which can coat the natural fibers and limit its ability to wick moisture/regulate temperature
  • Avoid using bleach and dry cleaning wool, chlorine can kill natural fibers
  • Avoid wringing out wool because it might stretch it
  • Avoid tumble drying merino wool or drying it near direct heat or sunlight for long periods of time, as heat can shrink the fabric
  • Wool items should not be ironed, but they’re naturally wrinkle-free
  • Ideally, wash merino clothing after a few wears to prevent shorter fibers to work their way to the outer surface. Make sure to air wool garments out to keep them fresh
  • Keep at least two pairs of socks, shirts etc. so you can switch between them without having to wash them during long trips


  • Hand-washable wool should be washed by hand in a basin without soaking it in soap for too long
  • The sink or basin should be clean and filled with warm water
  • Put just a few drops of detergent, preferably a mild one, liquid soap can also be used
  • Let the garment soak for 10 to 20 minutes (depending on the mass of the garment and stains)
  • Keep agitating water from time to time
  • Use a soft cloth to clean stained areas without rubbing hard. You can use a chlorine-free bleach to remove stubborn stains, but without stretching
  • Dry on a flat surface such as on a towel as drying on a hanger can change the shape and cause stretching
  • Flip from time to time, this might take longer to dry, but that’s an effective way of drying wool
  • You can also dry wool by hanging it over a chair in a well-ventilated space
  • Reshape the garment when it is still damp
  • Avoid wringing out the garment
  • Drain the basin/sink and rinse with fresh and mildly warm water

luxury wool sweaters in shop


When it comes to functionality, moisture-wicking, temperature-wicking, anti-microbial and quick-drying properties, merino wool is hard to beat. It’s a great material for hiking and backpacking apparel as well as for everyday use and traveling. Synthetic and other materials used in clothing might have their own advantages, but they cannot outweigh the benefits wool has to offer in most situations. If you don’t have an ultra-sensitive skin and a very limited budget, there is no reason why you should not consider merino wool, especially merino wool hiking socks and base-layers for your backpacking trips.

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merino wool - history, benefits, facts and uses

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Ralph S. is the founder of Silverlight, an avid hiker and trail runner he enjoys spending time outdoors, riding his motorcycle and swimming at the beach when he's not busy replying to customers or developing new Silverlight gear.

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