9 Facts About Wool: Wool Is Cool

Did ewe know that wool socks help keep smelly feet at bay? Or that wool is naturally flame-resistant? There are so many facts about wool that are not commonly known.

We’ve been enthusiastic supporters of British wool from day one. Why wouldn’t we be? Our brand is inspired by the adorable and lovable Herdwick sheep of the Lake District, and we’ve supported them and the Lake District fell farmers, through the Herdyfund, since the company launched in 2007.

Further reading: learn all about Herdwick sheep & The Herdyfund

There is so much more to wool than just using it for accessories or garments. In fact, the following may even surprise you.

Facts about wool no. 1: wool is flame-retardent

Fact about wool: wool is naturally flame resistant, with a high ignition point and smouldering properties.

Wool is a superb fibre when it comes to fire safety.

For a start, it has a ridiculously high ignition point of 570–600°C/1,058–1,112°F. Secondly, wool requires more oxygen than is actually available in the air to burn. And thirdly, wool does not melt, drip, or stick to the skin should it catch fire. In fact, it’s more likely to just smoulder briefly.

The very construction of the cell membranes in wool also prevents the spread of flame, and produces less smoke and toxic gas than synthetic fibres.

How come wool is so flame-resistant? It’s due to its naturally high nitrogen and water content (which also makes it a beautifully biodegradable product, see below).

Facts about wool no. 2: wool is renewable and biodegradable

Facts about wool: wool is biodegradable and really healthy for plants

As a modern society we are increasingly conscious of the effect plastics and synthetics have on wildlife and the natural world. This is why wearing wool is the perfect option for sustainability and environmental reasons.

It takes a year for a sheep to grow fleece and once shorn it will completely re-grow, providing a renewable source of fibre every year.

Wool is made from a protein called keratin, the exact same substance that our hair is made from. When wool degrades, naturally occurring fungi first attacks the ends of the wool fibre. Bacteria then eat the weakened wool fibre by secreting enzymes.

Wool contains a high percentage of nitrogen, around 17% (much higher than a lot of commercial turf products, which contain around 6% nitrogen). Plants require nitrogen for photosynthesis.

Wool also breaks down slowly, fertilising plants as it degrades and releasing nutrients back into the nutrient cycle. Wool products usually completely degrade after six months in the ground; by contrast, products made from synthetic fibres can take 30-40 years to degrade.

Wear wool, be green.

Wool facts no. 3: wool garments help reduce body odour

Another wool fact: wool garments help reduce body odour. Photo by USFWS Mountain-Prairie, licensed CC-by-2.0
Photo by USFWS Mountain-Prairie, licensed CC-by-2.0

Do you enjoy intense workouts like crossfit or powerlifting? Are you into long-distance running or cycling? Do these activities make you worry about body odour? Then wear wool!

Wait, what?

Wool has a natural ability to manage moisture by being extremely breathable. When we talk about breathability with textiles we’re talking about the material’s ability to transport moisture in the vapour state from an area of higher humidity to an area of lower humidity. In other words, the more breathable a product is the better it is at removing moisture from the microclimate (the space between your skin and the garment).

As a result, when you sweat, wool fibres wick away moisture effectively. Less moisture on your skin means less bacteria able to feed on your sweat, meaning less body odour.

Facts about wool no. 4: you’re probably not allergic to wool

Wool Fact: you're probably not allergic to wool. Photo by Denali National Park and Preserve, licensed CC-by-2.0
Photo by Denali National Park and Preserve, licensed CC-by-2.0

A common reason some folk shy away from natural wool garments and choose to wear man-made synthetic fibres is because they believe they are allergic to wool, or sometimes even lanolin (the wax/grease/oil that wool-bearing animals excrete).

The science suggests this is not actually the case. The National Center for Biotechnology Information notes that:

“Current evidence does not suggest that wool-fibre is a cutaneous allergen”

And that:

“contact allergy from lanolin, chromium and formaldehyde is highly unlikely with modern wool garments”.

In fact, the NCBI states that:

“Cutaneous irritation from wool relates to high fibre diameters (≥ 30–32 µm). Superfine and ultrafine Merino wool do not activate sufficient c-fibres to cause itch, are well tolerated and may benefit eczema management.”

What does this mean? Essentially, if your skin gets irritated by wool then it’s not about material itself, but rather how fine the wool is.

A thick and coarse wool, like from Herdwick sheep (35+ µm), is likely to irritate skin if you’re more sensitive to it. A finer wool, such as from Merino sheep, can often be as fine as 11.5–15 µm, and should present no trouble to sensitive skin.

Wool facts no. 5: wool retains its shape much better than most fibres

Another fact about wool: wool is able to retain its shape better and longer than most other fibres.

Wool is able to stretch to around 70% of its natural length and then spring back into its original shape, even after years of stretch, wear, and washing.

As a result, wool is a brilliant fibre for outdoor activity clothing. Not only will the wool garment regulate your body temperature, wick away body moisture, and reduce body odour, it will also naturally stretch and accommodate your body no matter what exercise you do.

Wool retains its durability and appearance much longer than other materials too, extending the life of the product. At the microscopic level a wool fibre is like a little spring that returns to shape after being contorted. It’s this property that makes wool garments naturally wrinkle-free. Wool fibres are also very strong and resistant to tearing.

Don’t buy into fast fashion, invest in longlife wool instead.

Facts about wool no. 6: wool is a natural insulator

Wool makes a wonderful thermal insulator, which is partly why we use it in our Herdysleep mattresses.

Wool fibres are crimped along their length. These natural curls create air pockets which act as a thermal barrier, naturally insulating against heat and cold.

Thermal conductivity is the ability for heat to pass from one side of a material through to the other. It is measured in W/mK (Watts per metre-Kelvin), and a lower number usually means a better insulator.

Sheep wool insulation has a thermal conductivity of between 0.035–0.04 W/mK, where as typical mineral wool has a thermal conductivity of 0.044 W/mK.

Wool helps you stay warm when the weather is cold and cool when it’s hot. That’s why we use it in our Herdysleep mattresses.

Wool facts no. 7: wool has a natural felting ability

Wool's scaly microtexture allows it to be felted together

The outside surface of wool fibres are covered in overlapping, serrated scales, similar to the scales of a fish. Wool is the only fibre with such serrations and it’s this structure that enable the fibres to cling together and produce felt.

Because of this unique property (ewe-nique?) wool felt is one of the oldest known human-made textiles, with examples dating back 6,000 years ago.

You can see this in action with our Herdy Felting Kit, where you can felt your own Herdy and in the process learn all about felting!

Facts about wool no. 8: wool is stain resistant

Wool is stain resistant due to the presence of lanolin in the fibres

The lanolin present in wool fibre creates a natural protective outer layer helping to prevent stains from being absorbed. This surface layer of lanolin is not easily removed by washing or processing.

What happens is water droplets on the surface of wool clothing will bead together and roll off, making the fibre somewhat hydrophobic, instead of being absorbed into the fabric, like with cotton. This allows wool to resist many common stains.

Great news when you spill your drink on the carpet!

No. 9: wool is the most recycled fibre

Wool is very widely recycled, making it sustainable and environmentally friendly. Photo by Lene Lyndrup, licensed CC-by-2.0.
Photo by Lene Lyndrup, licensed CC-by-2.0.

Wool is also one of the most sought after recycled textiles and can be made into a wide range of products such as garments, insulation, underfelt, mattresses and upholstery. This makes wool a supremely sustainable and environmentally-friendly fibre to use.

Ewe and wool

What's your favourite fact about wool? Do you have a treasured piece of wool clothing? Let's chat in the comments below, or join the flock on our Facebook, Twitter, Instagram, or email us.