This blog post is an overview of natural fibers in yarn. Knowing about the different fibers and their properties which can be used to create a yarn will help you make an informed decision when choosing a yarn for your next knitting project.
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As a starting point, you have to be aware that yarns can consist of either a single fiber or a blend of different fibers. In addition, there is also the option of mixing different breeds of the same fiber type. For example, a 100% wool yarn could consist of a blend of Polwarth, Romney and Hebridean wool.
Fibers in Yarn Overview
In general, you can choose between natural and synthetic fibers when it comes to yarn. Synthetic fibers are manufactured by chemical synthesis. Natural fibers, on the other hand, are derived from living organisms like plants or animals. Common synthetic fibers are nylon, acrylic and polyester. Their dominant disadvantages are that they are non-biodegradable and the fact that they consist of plastic which in turn leads to microplastic pollution during the washing process. 
Natural fibers are derived directly from nature. They are less resistant to sunlight, moisture and oils from the human skin compared to synthetic fibers. The fact that they are biodegradable makes them more sensitive. But they are often wonderful water absorbents and are generally comfortable to wear. 
Table of Content: Fiber Types
When it comes to natural fibers, you have to differentiate between two groups. On the one hand, there are plant or vegetable fibers, which are also called cellulose fibers.
On the other hand, there are animal or protein fibers. Let’s have a look at each category now.
Animal fibers consist of proteins and a small percentage of lipids. There are several different animals whose fibers can be used to create yarn. In general, animal fibers are measured in micron which is a scale unit for the diameter of the fiber. This characteristic determines the value of the fiber. The lower the micron count, the finer the fiber. For example, silk can have a micron count below 10 µm. The micron count of certain sheep breeds can go as high as 31 µm and up. However, this is highly dependent on the breed and the climate of the sheep’s location.
Wool is the most common fiber in yarn. It is derived from sheep by shearing them. Technically, the term wool is not specific to sheep, but since sheep wool is usually referred to simply as wool, this is the term I will use as well. Wool has several qualities that makes it desirable for the use in clothing. The wool fibers readily absorb moisture and have a high thermal resistance . They are also breathable and durable.
Despite common belief, cashmere is actually not produced by sheep. It comes from cashmere goats. Cashmere wool is associated with being extraordinary soft. The goats produce a double fleece with a fine undercoat and a coarser outer hair. Separating the under- from the outer coat will yield a very fine fiber. This can be done by combing. If the goats are simply sheared, the fleece contains a mixture of fine fibers and coarser hairs. 
Angora is a fiber that comes from Angora rabbits. It is popular for its softness and has a fluffy halo. Angora is also known for its silky texture. It is lighter and warmer than wool due to the hollow core of the fiber. 
It sounds confusing, but mohair is derived from Angora goats. Mohair is a fine fiber that is known for its luster and sheen. But although it is fine, it is still very durable. It has great insulating properties and takes dye very well. Like angora, mohair yarn also has a fluffy halo around it. 
Alpacas are closely related to llamas and are in fact often being confused. They are domesticated animals that are native to South America. Alpacas are bred specifically for their fiber. The fibers are harvested by shearing the alpacas once a year. The fleece is soft, making it a valuable fiber for clothing .
The llama is also a domesticated animal from South America. Originally, llamas were not bred for their fibers but for meat production and for the use as pack animals. But nonetheless, their wool is soft and contains only a small amount of lanolin (wool wax). 
Camels are ungulates in the genus Camelus that bear distinctive fatty deposits known as humps on its back. They have been domesticated to provide milk, meat and fiber. Camels are working animals especially suited to their desert habitat and are a vital means of transport for passengers and cargo.
Mongolian nomads and desert tribes use camel hair for tents, yurts, clothing, bedding and accessories. Camels have outer guard hairs and soft inner down.  Pure camel hair is recorded as being used for western garments from the 17th century onwards, and from the 19th century a mixture of wool and camel hair was used. 
Last but not least, there is the Yak fiber. Yak are a species of long-haired domesticated cattle. They can be found throughout the Himalayan region, the Tibetan Plateau and Mongolia as well as in some other regions. Compared with domestic cattle, yaks are rather large animals. They have long shaggy hair with a dense woolly undercoat. Domesticated yaks have been kept for thousands of years, primarily for their milk, fibre and meat, and as working animals. 
Yak wool is extremely warm, even warmer than Merino wool. The softness is comparable to cashmere. Like other natural fibers, it is breathable and odor-resistant. 
If you would like to give knitting with yak wool a try, have a look at mYak. While I have no personal experience with their yarns, I have heard only positive reviews and they offer a variety of different yak wool blends.
Silk is composed mainly of fibroin and is produced by different insect larvae to form cocoons. The most widely known silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori. Silk is produced by several insects; but, generally, only the silk of moth caterpillars has been used for textile manufacturing.
The process of silk production is called sericulture. It starts with cultivating the silkworms on mulberry leaves. Once the worms start pupating in their cocoons, these are dissolved in boiling water in order for individual long fibers to be extracted and fed into the spinning reel. To produce 1 kg of silk, 104 kg of mulberry leaves must be eaten by 3.000 silkworms. Since the process of harvesting the silk from the cocoon kills the larvae by boiling, sericulture has been criticized by animal welfare activists
The main silk producers are China and India. Silk production has a rather large carbon and water footprint.
Silk has a smooth, soft texture and is one of the strongest natural fibers. 
If you are looking for a 100% silk yarn, you should consider this one from Malabrigo and this one from BC Garn. Although I don’t have personal experience with these specific yarn bases, I have worked with yarns from both companies before and can recommend both brands.
On the other end of the natural fibers spectrum are plant or cellulose fibers. Cellulose is a polymer made of repeating glucose molecules attached end to end. Natural fibers are composed by microfibrils of cellulose in a matrix of hemicellulose and lignin. Since the natural fibers make hydrogen bonds between the long chains, they have the necessary stiffness and strength.
Cellulose fibers can either be natural – meaning that they are derived from plants and only processed as much as necessary for cleaning – or they can be manufactured. While manufactured cellulose fibers also come from plants, they are processed into a pulp and then extruded the same way synthetic fibers are. Examples for manufactured cellulose fibers are viscose and rayon. 
We are going to solely focus on natural cellulose fibers. If you are wondering why you cannot find bamboo listed below, you have to be aware that any fiber or fabric labelled as bamboo is usually viscose rayon, a manufactured fiber made by dissolving the cellulose in the bamboo, and then extruding it to form fibers. 
Now let’s have a closer look at the different types of natural plant fibers.
The most popular plant fiber is cotton. The fiber is derived from a shrub that is native to tropical and subtropical regions around the world. Cotton is most often spun into yarn or thread and used to make a soft, breathable, and durable textile.
The use of cotton for fabric is known to date to prehistoric times and it is still a very important commodity today. 
There is one major disadvantage to cotton which is its high need of water. Producing 1kg of cotton in India – which is the largest cotton producer in the world – consumes about 22.500 litres of water . When cotton is grown conventionally (instead of organic production), it is also a rather fertilizer and pesticides intensive process.
If you are looking for a yarn containing cotton, I can recommend two bases from BC Garn. First there is Allino which is a blend of 50% linen and 50% cotton. I have used it to knit a light summer cardigan a couple of years ago. The second one is called Bio Balance GOTS and is a blend of 55% wool and 45% cotton. I am currently knitting a cardigan for my mom using this yarn.
Linen or flax is a fiber that is derived from the flax plant. It is very strong and absorbent. Linen production also requires a lot less water and pesticide use compared to cotton making it a more sustainable alternative.
Linen textiles appear to be some of the oldest in the world; their history goes back many thousands of years. When buried in the soil, linen can degrade within a few weeks. This high biodegradability makes it even more ecofriendly.
Flax is grown in many parts of the world, but top quality flax is primarily grown in Western European countries and the Ukraine. 
In my Etsy shop, I offer a yarn that contains a blend of 85% wool and 15% linen. It is fingering weight and especially suitable for knitting socks, thanks to the strength and durability of linen. You can find it here. If you are looking for a 100% linen yarn, you could check out Lino Muka by Wollen Berlin. It comes in lots of different colors and is made from Lithuanian linen.
Hemp is a botanical class of Cannabis sativa cultivars grown specifically for industrial or medicinal use. Along with bamboo, hemp is among the fastest growing plants on Earth. It was also one of the first plants to be spun into usable fiber 50.000 years ago. Pure hemp has a texture similar to linen.
Hemp fiber is known to have high strength and durability, and has been known to be a good protector against vermin. In addition, hemp possesses the ability to absorb and release moisture without deteriorating.
The world-leading producer of hemp is China, which produces more than 70% of the world output. France ranks second with about a quarter of the world production. 
Ramie is a flowering plant in the nettle family Urticaceae, native to eastern Asia. It is one of the oldest fiber crops, having been used for at least 6.000 years, and is principally used for fabric production.
Ramie is one of the strongest natural fibers. It exhibits even greater strength when wet. Ramie fiber is known especially for its ability to hold shape, reduce wrinkling, and introduce a silky lustre to the fabric appearance. It is not as durable as other fibers, so it is usually blended with other fibers like cotton or wool. It is similar to linen in absorbency, density, and microscopic appearance.
Despite its strength, ramie has had limited acceptance for textile use. The fiber’s extraction and cleaning are expensive. Spinning the fiber is difficult due to its brittle quality and low elasticity. Weaving is complicated as well due to the hairy surface of the yarn. 
If you would like to give knitting with a ramie yarn a try, I can recommend the yarns from Ovis et cetera. She offers several bases that contain a blend of ramie and wool. I like the yarns so much that I used the Dimidium base (50% ramie, 50% ramie) to knit the sample for my very first knitting pattern, the Losing Sight of Shore Wrap.
Why Choose All Natural Yarns?
If you have been reading my blog posts before, are following me over on Instagram or Pinterest or are familiar with my Etsy shop, you might know that I exclusively use yarns that contain only natural fibers. This is due to a number of reasons.
Avoiding plastic whenever possible is important to me both in my business and my personal life. Therefore I only use yarn without any additional synthetic content (like nylon or polyester). Especially when it comes to sock yarn, nylon is often added to enhance the stability of the yarn. My yarns on the other hand are spun with a high twist to provide the necessary stability. One of my sock yarn bases, Merino Lino, contains linen to increase the durability of the socks.
Additionaly, my yarns are all non-superwash. A superwash treatment means that the yarn is machine washable and not prone to felting. It is usually done with a coating of polymer or resin or an acid bath to remove the scales of the fibers. This means that the wool loses some of its natural properties and gets covered in plastic. It is therefore not biodegradable anymore.
I encourage you to give knitting with all natural yarns a try! If you already have some experience with this, come share in the comments which natural fibers are your favorite!
Pin It For Later: Natural Fibers in Yarn
 Cumming, Valerie; Cunnington, CW; Cunnington, PE (2010). The Dictionary of Fashion History. Oxford: Bloomsbury. ISBN 9781847887382.