Estimated reading time: 7 minutes
- Properly classed wool will always be in demand among wool processors.
- The wool classification process focusses on six physical characteristics.
- As far as wool buyers are concerned, the most important characteristic of wool is its appearance.
- Wool colour, staple formation, and weathering of the tip all contribute to how wool presents.
- The style is determined by the clean yield, colour, as well as the evident and regular crimps in the staple.
The manner in which sheep are sheared, and how the shearing process is handled and the wool is classified, are processes that ultimately determine the income a producer can generate from a good wool clip. Many wool producers will attest to the fact that the shearing season is both a joy and a stressful time. This is because at the same time, the sheep’s wool must be sorted and classed correctly.
Properly classed wool will always be in demand among wool processors who want to use it for spinning. Stockfarm spoke with Jan Louis Venter, advisor at the National Wool Growers’ Association (NWGA) in the Free State, and Landrie Zietsman, Pinnacle BKB wool buyer and trader, to understand the terms and aspects pertaining to wool quality.
Physical characteristics
For a classer to correctly classify the physical characteristics of wool should be like making that first cup of coffee in the morning – it shouldn’t require much thought and must happen almost automatically. Since wool is sheared from different parts of a sheep’s body, there will obviously be differences in the physical characteristics of that wool.
The wool classification process focusses on six physical characteristics:
Length: The length of the wool is determined by the shearing frequency and feeding conditions. The target length of the sheared wool is usually around 70mm.
Tensile strength: Changes in feeding conditions play a significant role in wool’s tensile strength. If a sheep’s feed is drastically changed, it can lead to a weak link in the wool staple and therefore lower tensile strength, causing the wool to break easily during processing. The specific location where wool breaks in the staple is also important. If it breaks on the tip or root, it will not have a noticeable impact on the processing process compared to when there is a break in the centre of the staple.
Quality: The clarity and regularity of the wool crimps, the softness of touch (dull wool feels hard to the touch), and the purity of the wool determine its quality. Purity of wool means no other fibres are present in the wool.
Fibre diameter (micron): This is one of the most crucial price-determining factors. The micron as such is not the only aspect of micron that is relevant; the standard deviation (SD) is also of importance. The larger the SD, the more the fibres vary in fibre diameter, resulting in wool’s crimp becoming dull.
Clean yield: The amount of other material found in the wool will determine its clean yield. Pollution, among others due to dust, sand, wool oil, and plant material, plays a key role in the clean yield of wool. The type of plant material in the wool is also significant. For example, sticks and grass blades will comb out easily whereas clovers, burweed, and cocklebur can break the fibres during the removal process. Wool such as this will fetch notably lower prices than wool not contaminated with clover, burweed, and cocklebur.
Appearance: Wool colour, staple formation, and weathering of the tip all contribute to how wool presents. White to light cream coloured wool is usually preferrable. Dark cream coloured, yellow and brown wool is an indication of the wrong wool oil, which will cause the wool to not be completely white after washing. Wool that is permanently discoloured can only be dyed into darker shades than the wool itself, which will limit its uses.
Different main types of wool
- Fleece-wool types comprise fleece (new wool), back, neck and breech wool. Fleece wool is indicated by a length and fineness symbol such as AM, whereas back wool is marked BKS. Poor back wool and crow’s nest can be kept separately and are classed BKS2. Neck and breech wool can be classified together in a broken fleece line marked with a length symbol. Necks and breeches can also be packed separately if there is enough wool in which case the neck wool will be marked with a length symbol, for example, ANKS.
- Belly wool types comprise belly wool and skirtings. Both are separated by length and appearance. Wool that is longer than 60mm and attractive will be marked CBP. Wool shorter than 60mm will be marked BP. In the case of a short clip the BP line will be highly attractive whereas the less attractive pieces will be classified as BP2.
- Lox wool is primarily divided into four classes, namely LOX, LOX1, LOX2, and LOX3. Long head pieces (topknot) are packed in the LOX line. LOX1 wool is longer than 25mm, LOX2 wool is 25mm and shorter, and LOX3 contains manure, urine, and bloodstained wool.
Buyer and processor preferences
As far as wool buyers are concerned, the most important characteristic of wool is its appearance. Upon viewing a wool sample, a wool buyer can almost immediately make a deduction regarding its value. The style is determined by the clean yield, colour, as well as the evident and regular crimps in the staple. The test results are used to predict the wool’s processing behaviour.
Quality: Buyers will immediately reduce the value of wool contaminated with other fibres. Therefore, the wool must not contain any foreign fibres that can contaminate the entire clip. The appearance of foreign fibres in the wool can lead to an immediate claim against the buyer’s house by the processor, with consequent financial losses. This situation will cloud trust between a wool buyer and processor, and can lead to a wool buyer losing a dependable client. The buyer’s house will then keep a close watch on that producer’s clip for pollution, which will be factored into the price.
Typing: The various buyers’ houses utilise different standards to value wool, the most common having been modelled on the AWEX-ID classification system. This is the language that all the wool merchants and processors understand across the globe.
Micron: Micron also plays a significant role in wool price determination. The lower (finer) the micron, the softer the feel, the more durable the products made from it, and the higher the price.
Plant material: The less plant material present, the better, as the exporter wants to sell clean wool. The type of plant material present can mean a big difference in price.
Clean yield: Processors only want to buy clean wool. The cleaner the wool, the easier the washing and combing process. The more dust and plant material in the wool, the more likely the chances of it having to undergo additional washing or combing to get rid of the contaminants. – Carin Venter, Stockfarm
For more information, contact Jan Louis Venter on 083 650 1131 or janlouis@nwga.co.za, or Landrie Zietsman on 084 929 6206 or landrie.zietsman@bkb.co.za.
