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What Is Wool? And How To Buy The Best Sweater - Ever

Today I am answering the question - what is wool? So, if you have ever wondered how your ugly Christmas sweater is made, how the wool industry impacts our planet, and what you should buy for your vegan friends to keep them warm… well then, get ready to learn!

PS, one of my favorite parts of this article is teaching you the difference between a fast fashion $30 cashmere sweater and a luxury $300 or more sweater - so get excited.

But, before we get started

Have you heard about the super secret document that everyone in the fashion industry uses, but no one is talking about? Probably not. That is because you can't find it on Google or Instagram (believe me, I've tried).


It's a form I have used for over 13 years at every job I have ever had. Literally everyone from brands to fabric suppliers use it, but you can't find it anywhere publicly. 


The best part? It can cut your sourcing time in half, and save you tons of money in product development! This is the kind of info consultants charge the big bucks for. And, I'm giving it away for free until the end of the month. 


So, get ready to make fashion startup life a whole lot easier, and GRAB YOUR FREE DOWNLOAD OF THE NOT-SO-SECRET SOURCING DOC HERE


    what is wool mother gooses rock n roll mary had a little lamb

    You are probably thinking that's easy, it comes from sheep, like Mary's little lamb. Side note, because you know I love a good throwback that dates me - let me know in the comments if you remember watching Mother Goose's Rock 'n' Rhyme on Disney, above is Cyndi Lauper as Mary, with her Lamb - the early '90s were a wild time to be a child.

    Anyway… Wool is a generic term for animal fibers. Meaning, wool doesn’t just come from sheep. It comes from other animals too, like goats, camels, and rabbits. There are actually hundreds of animals that people from all over the world use to make clothing. But, in this article, I am only going to talk mostly about sheep wool. For some alternative sheep wool options, you can check out this post.


    what is merino wool

    Don't skip this part, it's going to be important in a little bit.

    Did you know that sheep didn’t always have wool?

    Before 10,000 BC (before domestication), humans would hunt sheep for their meat. Up until that point, sheep had a short and thick fur coat similar to that of modern-day deer.

    But, with the domestication of sheep, people started using them for their milk, making cheese, and not just meat anymore. Even the the skin was being made into leather. And, often the deer-like fur on the hide of the sheep was left on to increase warmth (kind of like the shearling, and the first-ever ancient Ugg boot).

    People started noticing that the hair around the sheep's stomach and the underside was a little longer and finer than the rest of the animal. And, that fiber could be used in yarn spinning. People then began selectively breeding sheep to produce the best and longest hair in the hopes of creating an animal with hair all over, that could be spun into yarns and textiles.

    By about 5000 BC people were able to use sheep's hair to spin wool yarn.

    Man created the modern sheep. Crazy right?


    what is felting

    When you break it down, wool is made of proteins and lipids (fats). As a quick refresher, fibers like cotton, hemp, and even rayon, are made from cellulose or plant-derived.

    What this means to your supply chain is that a totally different set of chemicals (dyes and finishes) need to be used to treat the wool fibers. Because on a biological and chemical level they are totally different and behave differently than plant fibers.

    For example, wool fibres react best when colored with something called acid dyes (don't worry, they aren't as scary as they sound). Acid dyes just mean that the dye bath needs an acidic pH. The acid used could be as mild as the vinegar you would find in your refrigerator. And, as an additional eco-friendly benefit, many acid dyes are actually non-toxic. Another benefit to wool and acid dying is that it's a pretty easy process, and comes in a wide range of available colors (which makes it fun for designers, and us as shoppers).

    If you're curious, and I know you are, cellulose dyes generally use a reactive dye which can have more environmental impact.


    what is worsted yarn

    Speaking of advantages to plant-based fibers…. Obviously, the biggest advantage is warmth. But, I guess that could be a disadvantage if you are in an extremely warm climate near the equator.

    Wool, because of lanolin - which is a natural oil from the animal skin, is also water-resistant. But, here is the problem. When wool is processed (read dyed or even just washed) the lanolin is removed and the fiber loses its natural water repellency.

    If you are looking to buy wool because you would like a naturally water-resistant garment, always make sure to purchase unprocessed wool. Which, BTW, can be a little bit stinky. If you see a bright red pea-coat that is being advertised as water repellent, you can assume that a synthetic waterproofing finish was added to the finished material.


    uses of wool

    So, what is wool used for? Besides clothing, wool has quite a few industrial uses, from piano dampers to the inside core of baseballs, to absorbent pads for those baaaaad oil spills we hear about on the news.

    Wool is incredibly warm. And, thank's to its natural fiber characteristics, it is also a pretty good option for more eco-friendly performance clothing. That is because it can be water-resistant, breathable, and good at wicking moisture.

    If you are curious about performance wool textiles you can skip down to the bottom of this article.


    what is wool used for

    Now, if you know me, and you have been following along with the virtue + vice blog for a while, then you know I am all about shopping for and buying the highest quality possible. And, usually, the first place to start researching when you want to determine quality is the fiber level. Wool is no different.

    Uniqlo is selling a $30 cashmere sweater. And, yes. while it technically is cashmere, it's total garbage compared to a Loro Piana.

    A lot of the time (like here in the case of luxury denim) price does not always equate to higher quality. I love proving that the expensive option is often a scam. But in the case of wool, IMO, the good stuff is worth it.

    And, I am going to teach you why.

    But, First, we need to ask ourselves, what characteristics determine wool's quality and value?

    In the fashion industry, we go by 4 different categories.

    1. Fiber diameter + length
    2. Crimp
    3. Color
    4. And, fiber strength.


    wool under a microscope

    Photo credit - 

    Ok, I am going to get very sciency with you right now. But, don't worry I know you can handle it.


    These are measured in microns (μm), which are one-millionth of a meter. In wool the finer (smaller) the diameter the higher the quality of wool. This is because finner fibers can be spun into finer yarns, which generally create fabrics with a more luxurious hand feel and drape. This is also true in the case of cotton. Options like Egyptian cotton, or Pima cotton will have longer fiber lengths, and skinnier fiber diameters, which lead to more expensive and luxurious textiles.

    Now, not only is the diameter important when evaluating wool, but also the uniformity of the batch. Having a wool blend with different size fiber diameters is a bad thing. We want them all to be about the same width for optimal fabric. That is why when we praise the value of wool we just don't just look at the length and width, but also the averages and ranges.

    So get this. The same cashmere goat can create a $30 sweater and a $300 sweater. And the price difference is totally justified.

    How is that possible?

    This is pretty cool. Remember when I explained to you how sheep were domesticated? There was a reason I got into that. I casually mentioned that even way back in the day, the softest parts of the animal were under their armpits and their stomach for a reason.

    That is still the case today.

    So using the same animal - the thick short bristly cashmere hairs on the back of the animal go to the $30 sweater. And all those soft, fluffy, luxurious hairs on the stomach make the cut for the $300 sweater.

    That is how Uniqlo and other low price cashmere sweater brands can say they are working with the same suppliers as luxury competitors.

    Tricky, tricky, tricky.

    An easy way to tell if you are getting the best and longest fibers is to look for worsted wool. Worsted wool goes through an extra selection process that picks out the very, very best fibers.


    Crimp is the natural kinks and waves in the fiber. I wish someone would have told this to my high school self who spent hours in front of the mirror straightening her hair every morning before school. But, the crimp is a good thing!

    Crimp is one of the factors that helps wool keep you warm. Because in all those tiny twists and turns, little pockets of air are able to form. And, air is a great insulator.

    Have you ever seen a duck in the wintertime ruffle its feathers? What that duck is actually doing is pumping the little spaces between the feathers with air, and that is what is helping it stay warm.

    As a general rule, finer fibers tend to have more crimp than thick and coarse wool fibers.

    With crimp, what we are looking for is uniformity. Fibers with even crimp throughout the fiber length have a higher value than irregular crimp.

    Now there is one more thing that helps wool keep us warm. It's not a characteristic that affects the quality. But, it is an important one to know about. And that is the scales of the fiber.

    On a microscopic level, wool has tiny scales on the surface of the fiber. These tiny scales are evolutionary and help to keep animals (and humans when we wear wool) warm. Just like crimp, scales are an even more microscopic way to trap more air, for even more insulation and warmth

    The only downside is that these scales are also itchy on the skin.

    Yes, you aren't crazy. Wool can be itchy.

    But, as we are learning, all wool is not equal. Wool that has a finer diameter is generally less itchy because the scales are smaller and more microscopic.

    Also, when fibers are too short they poke out of the yarns and cause irritation to the skin, the longer the fiber the less chance of this happening.

    But, even with the finest of wool fibers, it will always be itchy because of the inherent micro-scales on the surface. Some people with super sensitive skin will never be able to wear even the most finest cashmere in the world.


    Historically, dark color fibers have been undesirable and are sold at a lower cost. This is because darker colors are harder to dye. Fibers that are light colors, or white, are better because they are easier to add color to.

    Think about it this way. If you had a white piece of paper and a black piece of paper which would you pick if you only had a yellow marker to draw with? You would pick the white because the yellow wouldn't show up on the black background. The same theory is true for dyeing fibers.

    But, get this. The sustainable fashion movement has disrupted the wool fiber market. Dark fibers and fibers with color are a growing niche market share. That is because naturally colored fibers offer color and variation without needing to use a chemical dye process.

    By eliminating dying and using the fiber's natural colors, we are able to eliminate one of the biggest causes of water pollution in the fashion industry's supply chain and not skimp on creatively because we are still able to create interesting designs and patterns with different colors and shades.


    Lastly, wool that is strong is most desirable. I guess that is kind of obvious, right? We want fibers, yarns, and ultimately clothes that are going to stand the test of time.

    Processing wool is harsh on the fibers. And, wool fibers that can withstand the beating of being made into a sweater without breaking have a higher value because they create a better quality product.


    While I told you about what makes a high-quality would garment I also mentioned what makes wool so warm. So, If you are feeling a little overwhelmed by all this new info, I want to make it super easy for you. These are the 3 reasons why wool is naturally warm.


    Slow moisture absorption (read, good wicking).

    First, let's talk about the complete opposite. The secret to clothes that keep you cool when you work out is quick moisture absorption. When clothing pulls moisture from your skin quickly, it creates a cooling sensation.

    But, wool has slow moisture absorption. It absorbs so slowly, that it does not create a cooling effect on the skin. Yet, it absorbs fast enough that it is effective in keeping skin dry and less prone to feeling cold too. That's why you don't get clammy when you wear wool like you might when you wear something made of polyester.


    Air pockets.

    The natural crimp and scales on wool fibers create air pockets. And those air pockets are what keep you warm.



    There are lots of different types of sheep's wool, the most popular is Merino wool. All merino wool means is that it was grown on a merino sheep. And, merino sheep tend to have finer and longer hair than other types of sheep. So, it's a higher-quality sheep wool. But, is it as high quality as cashmere? Generally, no. Again, remember what part of the animal the hairs come from matters too.

    About 2 million tonnes of wool are produced annually, and 60% of that goes into apparel. By weight, China produces the most wool than anywhere else in the world, followed by Australia, and then New Zealand. Australia although second to China is still considered the world's leading producer of wool (and industry worth $3 billion) from its upward of 70 million sheep.

    A single sheep can produce anywhere from 2-30 lbs of wool per year.


    what are the uses of wool

    When it comes to wool, media and activists usually get caught up on animal rights issues. But, there is more going on in this animal fiber supply chain.

    Here's how to spot greenwashing.

    The tiny scales mentioned earlier that keep us warm, are also the reason wool cannot be machine washed. During washing, the tiny scales stick together and cause the fibers to clump and felt. They are also the reason why if you wash and dry your sweater, it will shrink to what I like to call Chihuahua size.

    Chlorinated wool was invented to try and combat this itchiness and shrinkage that is inherent to animal fibers. Basically, wool fibers are submerged in a chlorine bath. The chlorine bath chemically removes the scales from the fiber but leaves the rest of the fiber intact. We then have itch-free, machine washable wool.

    Chlorinated wool is not new. It has been commercially available in almost all wool manufacturing since 1893 when taught in Loewenthal’s “A Manual of Dying”.


    Chlorine on its own is not necessarily the issue. Actually, it kind of is. High exposure to chlorine has left workers with symptoms like pain, redness, and blisters on the skin, as well as coughing, and a burning sensation in the nose, throat, and eyes.

    Chlorine creates even more problems mixing into textile wastewater. Without treatment, chlorine bonds with carbon and creates adsorbable organic halogens aka AOX, which include dioxin. There are lots of different types of AOX, but we are mostly concerned with dioxins. Dioxins are card-carrying members of the dirty dozen - a group of particularly aggressive organic pollutants. AOX creation also happens in the production of vinyl, in dry cleaner fluids, household bleach, paper processing, and other industrial manufacturing supply chains.


    • a known carcinogen
    • an endocrine system disruptor in humans and wildlife
    • not able to break down easily in the environment


    what is wool


    The process of boiled wool originates as far back as the Middle Ages. Boiled wool is a type of felted wool similar to non-woven felt fabric.

    First, the yarn is knit into fabric. The fabric can be dyed, or left in its natural color. Then, the fabric is boiled in hot water and alkaline soap, this process is called fulling. The boiling causes the scales of the wool to stick together creating a felted fabric. The process creates a denser fabric, and up to 50 percent of the fabric's dimensions can be lost from shrinkage during this process. Because the scales are all stuck together from the fulling process, the fabric tends to be less itchy.


    Eileen Fisher is working on new technologies to eliminate the use of chlorination in wool with the help of BlueSign. The fall of 2015 was the release of their first season of chlorine-free wool. Here at virtue + vice, we are happy to see Eileen Fisher leading the way. Convincing mills to change their systems is costly and time-consuming. When large industry thought leaders push for these changes they open the gates for smaller companies (who can’t afford expensive research and development) to join the sustainable fashion movement.

    For more on what is wool's environmental impacts from chlorination, check out this report by Patagonia.



    Mulesing is one of the most controversial practices in wool production. The practice of mulesing removes strips of skin from around the buttocks of a sheep. This is to prevent the parasitic infection of flystrike (myiasis). The theory is that the fleece around the buttocks can trap feces and urine, which will then attract flies.

    By skinning the animal's buttocks, scar tissue grows back that cannot grow hair that will trap feces - preventing flies and illness.

    It's controversial.

    The National Farmers Federation of Australia argues that "mulesing remains the most effective practical way to eliminate the risk of 'flystrike' in sheep" and that "without mulesing up to 3,000,000 sheep a year could die a slow and agonizing death from flystrike".


    No. But, it is the most cost-effective way to treat animals.

    PETA advocates for better animal management systems. “Mutilating sheep is not just cruel; it’s also ineffective. Better husbandry is the answer, not mutilating animals. Prevention of maggot infestation through humane methods such as diet regulation, spray washing, and simply breeding types of sheep with better traits for the Australian climate is possible.”


    what is merino wool made of

    Organic wool certification, only certifies that the animal treatment is within organic standards. It does not certify the processing of the wool, which includes the treatment of the animals during shearing. Basically, all it means is that the animal if eaten meets organic standards.

    Here is what you get with organic wool.

    Feed and forage for the sheep from the last third of gestation must have organic certification.
    There are no synthetic hormones or genetic engineering of the sheep.
    No synthetic pesticides on pastureland or use of parasiticides, which can be toxic to both the sheep and the people.


    As this report from PETA shows, sheep can be kicked, beaten, stuck with clippers, and slammed against floors as shearers wrestle with them to shave the wool off their bodies. The Responsible Wool Standard “aims to prevent these practices through regulation, audits, and certifications”


    “The Responsible Wool Standard is a voluntary global standard that addresses the welfare of sheep and of the land they graze on. The certification is an independent, voluntary standard. On farms, the certification ensures the treatment of sheep with respect to their Five Freedoms and also ensures best practices in the management and protection of the land. Through the processing stages, certification ensures the identification and tracking of wool. There is annual auditing by an independent third-party certification body. As certified wool from these farms moves through the supply, the Textile Exchange Content Claim Standard is used to provide a chain of custody system to the final product. Each stage of production is certified to this standard by an accredited third-party certification body.”


    Personally, I have never been much of a fan of certification systems, even third-party ones. I have seen too many organizations doing the wrong thing pay their way into getting certified. That is why I think FiberShed is a much better solution to ethical and cruelty-free wool.


    Fibershed is amazing because it pools the resources of small farmers together so they can collectively act with power. I think we all agree that slow fashion is the answer to fast fashion. And, part of slow fashion is working with small local farmers.


    “Fibershed develops regional and regenerative fiber systems on behalf of independent working producers, by expanding opportunities to implement carbon farming, forming catalytic foundations to rebuild regional manufacturing, and through connecting end-users to farms and ranches through public education.

    We envision the emergence of an international system of regional textile communities that enliven connection and ownership of ‘soil-to-soil’ textile processes. These diverse textile cultures build soil carbon stocks on the working landscapes on which they depend, while directly enhancing the strength of regional economies. Both fiber and food systems now face a drastically changing climate, and must utilize the best of time-honored knowledge and available science for their long-term ability to thrive.”


    vegan wool alternatives

    Check out these wool alternative options, that will still keep you warm here. And, for everyone that is into wool but wants to make sure the animals are treated well. Try to shop from small local farmers (who really care about their animals) or from FiberShed.

    That's my best advice.


    what is virgin wool

    Today wool is not just for holiday sweaters, it is a performance fabric, thanks to some clever marketing. The companies using wool boast that their fabrics are naturally breathable, water-resistant, are great at wicking, help to regulate body temperature, and are even odor resistant.

    So, whats's the truth

    The sad reality is that the fibers undergo so much processing, they lose a lot of their natural characteristics. In the same way bamboo rayon has basically zero characteristics of bamboo.

    Let’s break down what you are really buying when you buy performance wool.


    Yes, wool, even treated wool, will be more breathable than synthetic alternatives.


    As I mentioned earlier, what makes wool water-resistant is the lanolin on the fibers. So yes, raw wool or virgin wool is water-resistant. But, when the fibers are processed all of that natural water resistance is lost.

    If the clothes you are buying are water resistance that means man-made chemical waterproofing was probably used.

    Some companies that are especially eco-friendly are skipping the chemicals and re-applying a natural lanolin finish after dying to restore the fiber's natural water repellency. If you want true, natural water-resistant wool, try buying oiled wool. Processing of this type of wool is done only in cold water to keep the wool's natural lanolin.


    While wool is technically moisture-wicking, any brand that claims that it is just as efficient or, even more, efficient than a petroleum synthetic fiber like polyester is lying.

    Here is why.

    While wool is very good at wicking, it is also pretty decent at absorbing. The outside of a wool fiber is made of fatty acid proteins and, does not absorb liquid very well. However, inside the fiber, there are salt linkages, and they are great at absorbing moisture that is in vapor form - like sweat.

    So yes, wool does absorb some moisture.

    Petroleum fibers like performance poly do not absorb moisture vapor the way wool does, so they wick 100% of the moisture away.


    As mentioned earlier, because of wool's love-hate relationship with moisture, it is actually pretty good at body temperature regulation. The fiber is good enough at absorbing moisture so you don't feel cold and clammy, but it doesn't absorb so much moisture that it ends up feeling like a cold, wet, cotton shirt.


    This claim also comes from lanolin. Lanolin is great at preventing bacteria (which causes a bad smell in clothes) from forming and growing. This is why oily Merino wool fabric doesn’t need washing and will still stay fresh and non-stinky after continued use. So, if the lanolin is lost during the washing process, so are a lot of the properties that keep you smelling fresh.

    Some brands say that because Wool will absorb moisture, it keeps you from sweating, and this, in turn, reduces body odor. I mean, isn’t that the same for every single natural fiber? They ALL absorb moisture. A generic statement like this isn’t specifically applicable to wool and seems like false advertising.


    That depends on your definition of eco-friendly. If it's simply not using petroleum-based fibers. Yea. I guess so. But, if your definition of eco-friendly includes ethics. You might want to dig a little deeper into the farming practices and treatment of the animals


    If there is something I forgot that you want to learn about let us know in the comments section.



    Ruthie Sakheim

    See above

    Ruthie Sakheim

    Top notch article, thank you.
    I’ve been wearing and loving wool since great aunt’s knitted sweaters that I wore in Maine and NY as a child. They even knitted me a bright blue snowsuit with a hood that kept me warm from head to toe! And I always wondered why those $30 cashmere sweaters were scratchy to the touch instead of deliciously soft! I’m trying to find out why you can’t send a wool sweater to England from the US? Any idea? Well, thanks!!

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