What Are Natural Fibers?

Natural fibers occur naturally in nature, naturally. (Sorry. Couldn’t resist.) It seems obvious, but it actually can be confusing. There are manufactured fibers that originate with or incorporate natural materials, but they are made by human hands (as opposed to extruded through our skin—yes, human hair can be spun, and it happens accidentally quite a lot when a piece of your hair falls onto the fiber you’re spinning). Regenerated or manufactured fibers that start with natural products such as bamboo, soy, or milk, for example, are not usually included in the natural-fiber category because of the processes that they have to go through to become fiber suitable for spinning. The term natural fiber refers to fibers that come directly from plants or animals. Examples of plant fibers include bast fibers, like flax and hemp, and seed fibers, such as cotton.

Bast fibers, from left: flax, hemp (left). Seed fibers, from left: cotton boll, cotton, colored cotton (right)

Plant and Animal

Plant fibers can grow off a seed (such as cotton), from the stem of a plant (such as flax or hemp), or even from the bark of a tree (such as the Western red cedar). Animal fibers come from the hair of animals such as sheep, dogs, llamas, bison (you get the idea—pretty much anything hairy is spinnable), but animal fibers also include the silk spun by worms and spiders—the most common is the silk from Bombyx mori silkworms. (And yes, you can spin spiderwebs—it is just hard to cultivate spider silk.)

Camelids, from left: camel, alpaca, llama (left). Goat, from left: Cashgora, Cashmere, Cashmere (right)

Cellulose and Protein

Plant fibers are composed of cellulose, while animal fibers are composed of protein. These chemical and structural differences mean that cellulose and protein fibers react differently when they are exposed to heat, water, soap, and dyes. Whereas extreme temperature changes can cause some protein structures to become permanently interlocked—as in felt—plant fibers can go through the same processes suffering no damage.

Sheep Wool, clockwise from top left: Masham, Merino, Black Welsh Mountain, Icelandic, Norwegian

Plant and animal fibers also react differently to pH levels. Protein can be damaged by high pH levels (alkaline—think baking soda), but respond well to low pH levels (acid—think vinegar). Soda ash is alkaline and is a common water softener used in many laundry detergents. This is why, when washing wool and other protein fibers, most people encourage the use of wool-safe detergents and a vinegar rinse. Cellulose and protein fibers take dye differently. In most cases, fiber-reactive dyes are used to dye cellulose fibers, and acid dyes are used to dye protein fibers.

Silk, from left: silk noil, tussah, bombyx (left). Yak (right)

This is only the tip of the iceberg as far as different types of fiber. What is the most unusual thing you have spun? We love to hear from our readers! Please share your fiber stories and photos here.

Resources

• McCuin, Judith MacKenzie. The Intentional Spinner: A Holistic Approach to Making Yarn. Loveland, Colorado: Interweave, 2009.

Amy Clarke Moore is a former editor of Spin Off.

This article was published in the Winter 2010 issue of Spin Off.

Also, remember that if you are an active subscriber to Spin Off magazine, you have unlimited access to previous issues, including Winter 2010. See our help center for the step-by-step process on how to access them.

Originally published November 30, 2020; updated October 7, 2022.