Material
Most of the fiber from domestic sheep has two qualities
that distinguish it from hair or fur: it is scaled in such a
way that it helps the animal move out burrs and seeds that
might embed themselves into its skin; and it is crimped, in
some fleeces 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 fibers "grab"
each other so that they stay together. They also make the
product retain heat, as they trap heat in their bends.
Insulation also works the both ways;
bedouins and
tuaregs use wool clothes to keep the heat out.
The amount of crimp corresponds with the fineness of the
wool fibers. A fine wool like
merino may have up to a hundred crimps per inch, where
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.
Wool grows in several natural colors such as black, brown
(also called moorit) grey and the most commonly available
white. Wool of any color takes
dye easily and can be
felted.
Wool straight off a sheep is highly water-resistant. It
is said to be "in the grease", the grease being
lanolin, and can be worked into yarn and knit into
water-resistant mittens, as did the
Aran Island fishermen. Wool retains heat better than
most fabrics when wet.
The spinning capacity of wool is determined by the
technique known as
wool classing, whereby a qualified woolclasser might
group wools of similar gradings together to maximise the
return for a farmer wishing to yield the most from the
sheep's fleeces.
Processing
Wool straight off a sheep contains a high level of grease
which contains valuable lanolin, as well as dirt, dead skin,
sweat residue, and vegetable matter. This state is known as
"grease wool" or "wool in the grease". Before the wool can
be used for commercial purposes it must be scoured, or
cleaned. Scouring may be as simple as a bath in warm water,
or a complicated industrial process using detergent and
alkali. In commercial wool, vegetable matter is often
removed by the chemical process of chemical carbonization.
In less processed wools, vegetable matter may be
removed by hand, and some of the lanolin left intact through
use of gentler detergents. This semi-grease wool can be
worked into yarn and knitted into particularly
water-resistant mittens or sweaters, such as those of the
Aran Island fishermen. Lanolin removed from wool is widely
used in the cosmetics industry, such as hand creams.
After shearing, the wool is separated into five main
categories: fleece (which makes up the vast bulk), broken,
pieces, bellies and locks. The latter four are pressed into
wool packs and sold separately. The quality of fleece is
determined by a technique known as
wool classing, whereby a
qualified woolclasser groups wools of similar gradings
together to maximise the return for the farmer or sheep
owner. Prior to Australian auctions all Merino fleece wool
is objectively measured for micron, yield (including the
amount of vegetable matter), staple length, staple strength
and sometimes color and comfort factor.
History
As the raw material has been readily available since the
widespread domestication of
sheep and similar animals,
the use of wool for clothing and other fabrics dates back to
some of the earliest civilizations. Prior to invention of
shears - probably in the Iron Age - they probably plucked
the wool out by hand or by bronze combs.
In medieval times, the wool trade was serious business.
English wool exports - which bordered on European monopoly -
were a significant source of income to the crown. Over the
centuries, various British laws controlled the wool trade or
required the use of wool even in burials. In 1699 English
crown forbade its American colonies to trade wool with
anyone else but the England itself.
In the Renaissance, Medicis of Florence built their
wealth and banking system on wool trade with the aid of the
Arte della Lana, the wool guild. Spain allowed export of
Merino lambs only with royal permission. German wool -
based on sheep of Spanish origin - begun to overtake British
one only at the end of 19th century. Australia's colonial
economy was based on sheep raising and Australian wool trade
overtook Germans by 1845.
