Boiled wool is a special type of fabric primarily used in berets, scarves, vests, cardigans, coats and jackets. Created by a mechanical process using water and agitation, shrinking knitted or woven wool or wool-blend fabrics, compressing and interlocking the fibers into a tighter felt-like mass.
Wool felt and felted wool are similar to boiled wool, all of these processes date back to at least the Middle Ages. The word felt itself comes from West Germanic feltaz. Boiled/felted wool is produced industrially around the world and is characteristically found in the traditional textiles of South America and of Tyrolean Austria.
Boiled wool/felt yardage is created commercially by first weaving or knitting wool fibers resulting in a fabric of uniform thickness. The material may either be dyed first or left natural, with or without design and embellishment. It is then "boiled" and agitated in hot water and suds, shrinking the fabric without the use of chemicals. The result is a tighter and more dense material, usually shrinking anywhere from twenty to fifty percent. Wool that has been boiled/felted is thought to be warmer, more durable, and windproof.
In strictly woven fabrics, as opposed to knits, there is a similar wool finishing process called fulling.
- "Felt". Online Etymology Dictionary.