To do crocheting, knitting, knotting, or weaving, the fiber artist first needs yarn. That yarn can be made from any of a multitude of fibers. Learn the characteristics of various fibers so you can better select yarn for the effect you want in any project.
The animal fibers include those spun from the wool or hair of animals, as well as the silk spun by the silkworm caterpillar. Wool and hair fibers include sheep’s wool, of course, as well as mohair, llama, yak, angora, alpaca, etc. Some hand spinners have even added dog hair to wool blends!
Yarn spun from animal fibers is breathable (allowing air circulation) and comfortably warm or cool, due to insulating properties of animal fibers. Knitters can find wool yarn as fine as a cobweb for lace shawls or as bulky as the lopi roving used for heavy winter sweaters. Luxury fibers like angora or silk may be blended with wool. Animal fibers have elasticity, and thus more wrinkle resistance than plant fibers. They are also susceptible to insect damage.
Wool yarns are made by first shearing or cutting the yarn or hair from the animal, then carding the fibers till they are untangled and ready for spinning. After spinning, two or more of the spun threads (called “singles”) may be twisted together to form 2-ply, 3-ply or 4-ply yarn. Some wool yarn is further processed to make it machine washable. Unless wool is labeled “superwash” it must be gently hand washed to prevent shrinking and felting. Some knitted projects are intentionally made at a loose gauge in a large size and intentionally felted.
Silk thread is unwound from cocoons, then processed into yarn. Silk threads are lightweight and lustrous, yet surprisingly strong for their weight.
Other fibers come from plants. Bast fibers such as linen and hemp come from the stringy insides of the stems of the plants. Cotton comes from the fluffy bolls of the plant.
Plant fibers are strong, but not elastic. They are breathable and absorb moisture, making them good choices for summer knitting. Garments made from plant fibers will shrink when washed unless the yarn is treated to be shrink-resistant. They are vulnerable to damage from sun and mildew.
Cotton is popular for dish cloths in worsted weight, lace doilies in fine cotton thread, and a variety of warm-weather garments in sport weight. Linen costs more, but has added luster and softness. Organic cotton has been grown to specified standards without pesticides.
Like the animal fibers, plant fibers readily accept dyes and come in a wide range of colors.
While the natural fibers come from a natural substance that is rearranged through combing, blending, and spinning into threads, the synthetic fibers are a combination of natural fibers with chemicals or are completely chemical in origin. Advantages include strength, durability, and wrinkle resistance. Other characteristics may be engineered into the yarn as well, such as antimicrobial qualities.
The cellulosic fibers begin with wood pulp or similar matter from bamboo or other plants. The cellulose is chemically processed into a silk-like fabric. Rayon, the first artificial fiber, was called “artificial silk.” Rayon has some breathability, like a natural fiber, and is more affordable than silk. It is less durable than silk, but drapes and takes dyes well. Rayon yarns are very soft, excellent for garments to be worn against the skin. Acetate and triacetate are also cellulosic fibers.
Finally there are the yarns from chemical sources. Acrylic is the most common. The vast majority of yarn in department stores is acrylic. Other chemical fibers include polyester, nylon, spandex, olefin, modacrylic, etc.
Acrylic yarns come in a wide range of qualities and weights. Some cheap acrylic is scratchy to the skin or has a plastic feel. Better acrylics may be soft as lambswool, textured for special effects, or blended with wool for superior comfort. Try several varieties, crocheting a swatch with each. Wash the swatches, then compare the feel and look of them to find an acrylic you will enjoy working with.
Spandex or elastic may be added to yarns to provide extra resilience. Use these blends for close-fitting garments like socks or items that need extra stretch, like headbands.
Be advised that synthetic fibers are highly heat sensitive. Avoid ironing, hot dryers, etc. Synthetic fibers melt when exposed to high heat.
Mineral Yarn Fibers
Some novelty yarns include metallic or glass fibers, such as lurex. These fibers are used in small amounts, so the yarn will have the characteristics of the main fiber, whether natural or synthetic.
In conclusion, your yarn choice depends upon the pattern recommendations for your project. You must also consider comfort, cost, and appearance. Always crochet a sample (swatch) before beginning a project in order to check for satisfactory drape, texture, and gauge.