Learn about different wool characteristics — from fiber length and diameter to crimp.
With this compact, portable reference in hand, crafters can quickly and easily look up any of 100 sheep breeds, the characteristics of their fleece, and the kinds of projects for which their fleece is best suited. Each breed profile includes a photo of the animal and information about its origin and conservation status, as well as the weight, staple length, fiber diameter, and natural colors of its fleece. The Field Guide to Fleece (Storey Publishing, 2013), by Deborah Robson & Carol Ekarius, is a great primer for beginners, and a handy guide for anyone who loves working with fleece! The excerpt below comes from the introduction, “A Love Affair with Wool.”
You can purchase this book from the MOTHER EARTH NEWS store: The Field Guide to Fleece.
We love wool. We love sheep. That’s why we wrote The Fleece & Fiber Sourcebook. Many readers have asked for a smaller book that they could carry with them or give to friends who are new to fiber arts. We listened!
Why are we so fond of wool? Well, first, it is all natural. It’s also surprisingly diverse and exceptionally practical. It provides warmth in cold climates, while it also makes a great cool fabric for warm weather. Desert-living people — from Navajos to Bedouins — have long histories with sheep and wool.
Not all wools are created equal! There are more than a thousand breeds of sheep, each with its own intrinsic wool characteristics. Some grow negligible wool, while others have superlong fleeces. Some fine wools can be worn comfortably by babies, while strong wools can last for centuries in heavily used rugs. Some wools felt readily, while others won’t felt at all. Some are springy, while others are dense and supple. For us, learning about these diversities of sheep and experimenting with their wools is a great adventure.
Fiber characteristics vary widely not only between breeds but also within breeds, and sometimes even throughout an individual fleece. Wool changes with an animal’s age, health, and environmental circumstances. A lamb’s first fleece will be its finest and softest. A sheep that was sick or subjected to other stress may grow a fleece with weak spots. The next year that same animal could grow strong and beautiful fiber. Every fleece has distinct, individual qualities.
Wool comes in many natural colors, but it can also be dyed. White wool is the usual choice for dyeing, while overdyeing naturally colored wools can create lovely, nuanced colors. Wools from different breeds take up dyes differently. Dyeing offers infinite possibilities!
When you are learning to tell one wool from another, consider its crimp, fiber length, and fiber diameter, and look at the types and mix of fibers in the fleece.
Crimp, which consists of the natural kinks or waves in individual fibers, forms as those fibers grow; it is permanent. Crimp can be tight and well organized, or loose and disorganized. The crimpier the wool, the more elasticity it has, so crimpy wools make great socks or other items that need to stretch and rebound. Wools with less crimp drape elegantly.
Our estimates of fiber lengths represent common annual growth. Many fleeces fall outside those ranges.
Historic grading approaches, like the Bradford Count and Blood Count, were based on the educated fingers and eyes of trained evaluators. Technology has allowed us to report fiber diameters based on micron counts. A micron is a measurement equal to one-millionth of one meter. An interesting thing about micron counts is that two fibers can report the same micron count, yet feel different in your hand. Think of it as two pieces of paper that weigh the same, but one is slick magazine-type paper and the other a natural rice paper: you know the difference as soon as you feel them, even if they weigh the same. And trained or not, our sense of touch is still one of our best guides to fiber quality.
Single-Coated and Double-Coated
A fleece can be single-coated (containing only wool); double-coated (containing two coats, a coarse outercoat and a fine undercoat); or composed of three types of fibers (add in kemp).
Wool, Hair and Kemp
The term wool can apply to an entire fleece, but it also refers to a specific type of fiber within a fleece. Wool fibers are relatively fine, and have crimp and elasticity; even coarse wool fibers are much finer than hair fibers. Hair fibers are straighter, smooth, strong, and inelastic. Kemp fibers are coarse, brittle, and almost always shorter than the other fibers. Dye “hides” in the hollow centers of kemp, a trait that is used in producing true tweeds.
Read more from The Field Guide to Fleece:
This excerpt has been reprinted with permission from The Field Guide to Fleece, by Deborah Robson and Carol Ekarius and published by Storey Publishing, 2013. Buy this book from our store: The Field Guide to Fleece.