Fleece

Wool is the fibre derived from the hair of animals of the Caprinae family, principally sheep and goats, but the hair of other mammals such as alpacas may also be called wool. This article deals with the wool produced from domestic sheep. more...

Wool is the fibre produced as the outer coat of sheep. Most of the fibre from domestic sheep has two qualities that distinguish it from hair or fur: it has scales which overlap like shingles on a roof and it is crimped; in some fleeces the wool fibres have more than 20 bends per inch.

Both the scaling and the crimp make it possible to spin and felt the fleece. They help the individual fibres attach to each other so that they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles and retain air, which causes the product to retain heat. Insulation also works both ways; bedouins and tuaregs use wool clothes to keep the heat out.

The amount of crimp corresponds to the fineness of the wool fibres. A fine wool like merino may have up to a hundred crimps per inch, while the coarser wools like karakul may have as few as one to two crimps per inch.

Hair, by contrast, has little if any scale and no crimp and little ability to bind into yarn. On sheep, the hair part of the fleece is called kemp. The relative amounts of kemp to wool vary from breed to breed, and make some fleeces more desirable for spinning, felting or carding into batts for quilts or other insulating products.

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