The most ancient and widespread protein fiber is wool, derived from the hair grown on sheep. However, various animals, including goats, camels, rabbits, and even household pets and humans, also produce protein fibers. Much like human hair, protein fibers exhibit significant variations depending on the animal species and specific breed. They can differ in length, thickness, structure, and even curvature, ranging from straight to curly or wavy.
Under a powerful microscope, these fibers reveal a distinctive feature they are covered with tiny scales, resembling the scales of a fish. Run your fingers along your hair, and you will experience the subtle drag and resistance caused by these scales moving in different directions. The section dedicated to scales is crucial as they profoundly influence the appearance, texture, and behavior of protein fibers.
Scales act as miniature fingers, playing a vital role in holding fibers together during the spinning process, forming a robust and durable yarn. Simultaneously, they provide a microscopic buffer between fibers, creating a delicate balance between entanglement and separation. Notably, scales contribute to the phenomenon of felting, as evident in the shrinkage of a wool sweater when subjected to hot soapy water.
A fundamental rule is that finer fibers possess finer and more numerous scales, while coarser fibers have larger and fewer scales. For instance, superfine Merino fibers may have up to three thousand scales per inch, imparting a virtually imperceptible smoothness. On the other end of the spectrum, longwools and rougher fibers have larger scales, potentially creating a coarser feel against the skin.
Scales also play a role in the warmth of a fiber by trapping still air within their nooks and crannies, a crucial factor in creating warm and insulating textiles.
Woolen-spun fibers, where strands are jumbled, can create surprisingly warm fabrics due to the trapped air. In contrast, worsted-spun fibers, aligned and combed, tend to be denser and less warm. Silk, a unique protein fiber, stands out for its scale-free surface, contributing to its brilliant reflective qualities and slippery nature.
While scales are a defining characteristic of animal-produced fibers, certain fibers like silk and plant-based fibers (cotton, linen, rayon, Tencel) lack these scales. This intricate interplay of scales, fiber structure, and spinning techniques enriches the world of textiles, offering a diverse range of materials with distinct qualities and characteristics.
Wool in the realm of yarn is akin to the diverse array of restaurants scattered throughout San Francisco. One could embark on a knitting journey, exploring a different wool blend each day for an entire year without encountering the same yarn twice. The spectrum of wool is as varied as the sheep that yield it, ranging from robust and rope-like to delicate and ethereal, with a multitude of textures in between. Even within a single sheep breed, subtle distinctions emerge, influenced by factors such as individual animals and varying farming practices. For a deeper dive into specific sheep breeds and the fibers they produce, Nola Fournier and Jane Fourniers "In Sheep's Clothing: A Handspinners Guide to Wool" is a highly recommended resource. Here, our focus shifts to wool in the context of commercial yarns.
The journey of obtaining wool begins with the shearing of sheep, a practice typically conducted twice a year once in spring and once in fall. The length of the fiber, known as staple length, varies from around 2 inches (5 cm) in fine wools to 12 inches (30.5 cm) in longwools. The sheared mass of fiber, termed a fleece, encompasses everything present on the sheep at the time of shearing, including vegetable matter, dirt, and lanolin a greasy substance secreted from the sheeps sebaceous glands. Lanolin, apart from repelling water from the sheeps coat, may also contribute to skin protection.
The cleanliness of wool, post-processing, varies based on the level of stringency applied. It can range from impeccably clean, akin to fine, triple-sifted cake flour, to more au naturel with additional vegetable matter and lanolin in the fiber reminiscent of a hearty whole grain. Traditional fishermens sweaters often utilized lanolin rich yarn to enhance warmth and dryness during stormy seas.