Wool processing is the multi step process of turning raw wool into finished product.
The basic steps
Carding or Combing
Scouring, the technical term for washing, is the first step in wool processing. This involves washing the wool in hot soapy water to remove dirt, grease and dry plant matter from the fleece.
The preferred water temperature for washing wool is 140 degrees Fahrenheit.
Soaps of various natures have been tried with much success. For those washing wool in their home, Dawn dishwashing soap seems to be a favorite. Use a mild soap, nothing harsh. Commercial processors may use a slight alkaline solution (by adding sodium carbonate) to aid in the scouring process.
The key is to keep the water temperature and the volume of soap used as low as possible while still being able to wash out the grease and dirt. Wool that is very greasy will require hotter and stronger solutions to remove the grease.
In the scouring process the wool undergoes several soaks and rinses until the wash water remains clean. It is preferable to let wool soak and avoid agitation.
Each subsequent wash is a weaker solution of soap or alkaline until the final wash is only water. Between each wash the wool is pressed or squeezed to remove excess water.
At each wash step the wash water can be retained for subsequent batches of wool until the first wash becomes to dirty for further use.
At this point the second wash can be used as the first by bringing it up to temperature and adding soap to bring it up to start point. Each subsequent wash would move up the chain so that the last rinse is always being replaced with clean water. This way water and energy to heat it, is being conserved.
When washing wool on the ranch consideration must be given to the quality of the water. Just as you would not wash your clothes in water that has an excess mineral content (like iron) you do not want to wash your wool in the same type of minerally imbalanced well water.
After washing and thorough rinsing the wool is dried. On a commercial scale large mechanical dryers are used. The wool is set on screen tables with hot air circulation. On a individual scale the wool can be placed on a sheet and set in the sun.
Carding or Combing
In researching wool processing information there was some confusion between these two terms. Many recent sources do not mention combing at all and older sources talk of it as something entirely different from carding. Nowadays, the terms combing and carding are often used interchangeably and the more common term of carding prevails.
As far as we can discern, carding is gently spreading washed and dried wool in preparation for further processing.
Combing is straightening and stretching the fibers to obtain maximum spinning capacity.
For carding the shorter wools are preferred and for combing the longer wools are preferred. The shorter carded wools are generally the ones that will be processed into clothing.
Carding is a hand or mechanical process. Individuals can purchase hand carders while commercial processors will use mechanical machines. Either way, steel fingers seperate and straighten the fibres and then twist them back into one another again thus forming strings of wool. These strings are again twisted into one another to produce longer continuous ropes of wool called rovings.
Any dry plant material still in the wool will fall out or should get picked out during the carding process.
At this stage of the wool processing the paths can diverge. Dependent on the quality and type, wool will either be used for the purpose of spinning or will make its way to the felting table.
Spinning is the process where the wool rovings produced during carding, are turned into yarns. On a commercial wool processing scale the rovings pass through a spinning machine. On an individual scale a spinning wheel or a hand spindle is used. During spinning the wool rovings are gently stretched again. Through a series of twisting and spinning and twisting again the wool is spun into batches of similar quality and strength.
The spun wool is formed into and stored as skeins of yarn, what you see and buy in the store. These are small bundles of yarn that can now be dyed if warranted.
During the spinning process other fiber types may be blended with the wool to create various and more unique yarns.
Once yarn is produced (or purchased) it can be used for weaving or knitting. What's the difference between the two?
Weaving is taking strings of yarn, setting them at right angles to each other and interlacing them over and then beneath each other thus forming a woven mat.
Knitting is done by forming loops of yarn and interlocking rows. You are continually forming new loops and passing a string of yarn through it.
Felting can occur after carding and instead of spinning.
Felting is a feature of wool that enables it to form mats of fabric because the fibers can interlock with each other. How much it can felt is dependent on the fineness or coarseness of the fibers. The finer wools felt better due to the finer crimp which results in more ridges and a tighter lock or joining.
In the process of felting the wool is subjected to moisture, pressure and gentle beating action. Layers of wool are laid at right angles to one another to establish fibers that run lengthwise and then crosswise and then lengthwise again. The felting machine applies steam moisture and pressure along with a back and forth action to felt the wool. As the fibers shrink they become entangled together and form a strong, durable felted mat of material.
Wool can be felted to the point where it is impossible to distinguish the fibres in the material or to pull it apart as the fibers have become so entangled and tightly meshed. Felting done to this extent is then called fulling.
As wool readily accepts dye colors, dyeing can occur at almost any stage of the wool processing. The two common stages for wool dyeing is right after washing or after spinning wool into skeins of yarn.
If the dyeing occurs after the wool is washed then it is referred to as stock dyed wool. If the wool is dyed after it is spun into yarn then it is referred to as yarn dyed.
Many subtle dye colors can be extracted from various plants for a natural dye process. On a large commercial scale the use of chemical dyes is more convenient and thus more common.
Sheep producers selling raw wool directly to market after shearing rarely concern themselves with the wool processing steps. They really don't need to.
Yet if you want to save a fleece or see it turned into a product for your home or for a friend it is valuable to learn about wool processing. And if you are producing wool it is valuable to learn about the properties and characteristics that make wool such a unique and multifaceted fiber material.