Wool remains a valuable material used to produce different things, including clothing, household goods, art, and insulation. However, since wool is available in different types, its quality also differs. So, the need to want to know how to tell wool quality to avoid being scammed is understandable.
Quality plays a huge role in determining the price of wool, so you will typically pay more for higher-quality wool and less for lower-quality wool. Despite having different qualities, all wool is valuable, and proper preparation helps maximize the returns.
Keep reading for a detailed look at the factors determining wool quality.
Features That Determine Wool Quality
You can gauge the quality of wool by considering different aspects. These include yield, purity, fiber diameter, staple strength and length, color, and crimp. This section discusses each factor to provide a better understanding of them and, in turn, the quality of wool.
1. Fiber Diameter
It is also known as fineness and refers to the wool fiber’s diameter measurement. The fiber diameter determines how thick the yarns made of it can be. Fineness’s unit of measurement is microns (μm) which translates to a millionth of one meter.
Each fleece typically comprises an extensive fiber diameter range. For instance, a standard merino fleece contains fibers with a diameter of 10 microns, while other fibers can have diameters of over 25 microns, depending on the sheep’s age, nutrition, or health.
Fine wool has a smaller diameter; the lower the fiber diameter, the finer the fleece. Usually, wool with fiber diameters between 11.5 μm and 24 μm is used to make clothing.
On the other hand, anything higher is used to manufacture textiles like blankets, furnishings, and insulation.
- Superfine wool- it has a fiber diameter of 15 μm to 18 μm
- Fine wool– it has a fiber diameter of 18 μm to 22 μm. Merino sheep wool is usually under this category.
- Half-blood wool- the fiber diameter is 22 μm to 25 μm.
- Medium wool- the fiber diameter is 24 μm to 30 μm.
- Braid wool- it has a fiber diameter of over 30 μm.
2. Fiber Diameter Uniformity
This factor is also essential because although having varying fiber diameters in a sheep’s fleece is normal, excess variation in the grade (fineness) is undesirable. Wool with a higher fiber diameter uniformity is more valuable.
This refers to the wool fiber’s repeated waviness or natural kinks. Although every sheep wool has a crimp, the amount differs based on the individual sheep and breed. Generally, finer wools contain more crimps compared to long and medium-long wools.
Wool with more crimps is considered more valuable because crimp gives wool more bulk, makes it springy and soft to the touch, aid in heat retention, and improves insulation.
As mentioned earlier, the sheep breed determines a sheep’s crimp amount. For this reason, some breeds with higher crimp levels include the Rambouillet and Merino. A Merino can have up to 100 crimps for every inch, depending on the type.
On the other hand, breeds such as Wensleydale and Lincoln Longwool have hair-like wool with excessively little crimp. In addition, sheep whose wool parts midway and then falls to its sides contain lower crimp levels.
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This refers to how much clean fiber, when the moisture content is standard, is anticipated to be generated once a raw wool parcel is processed. Essentially, it is how much wool you will have left after scouring. It is essentially the raw wool mass in percentage and clean mass expressed in kgs (kilograms) before processing.
Wool shrinkage comprises dirt, lanolin (wool grease), sand, vegetable matter (VM), and dust. Yield can vary significantly; for instance, it can be 40% to 70%, with the figure influenced by different environmental and genetic factors.
To calculate yield, you must first determine the quantity base of Vegetable Matter and Wool Base (clean, dry fiber). Before calculating the Wool Base, you must first measure the residual components.
The residual components comprise:
- Wool’s Residual Grease (RG) refers to the tiny grease amount left behind once you scour wool. Near-Infrared Reflectance Spectroscopy (NIRS) determines the amount.
- Ash- the process of wool scouring eliminates nearly all dirt aside, leaving behind tiny amounts determined with the help of NIRVM. The Vegetable Matter, which is then dried and weighed, is obtained by dissolving the scoured wool’s sub-sample in a 10-percent heated caustic soda solution.
- Vegetable Matter comprises Hard Head & Twigs (H), Seed and Shive, and Burrs (B).
After measuring the residual components, the dry, clean fiber can be calculated. This is done by expressing the wool weight with the removed impurities as the weight percentage of the primary scoured wool. Wool base helps to calculate different commercial yields.
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5. Staple Strength and Length
This refers to an unstretched fiber’s measured length, spanning from base to tip. The wool’s value increases with the staple’s length, with longer ones being more valuable. The staple length of sheep wool varies considerably based on breed, but a good length ranges from 2 to 8 inches.
The staple weight is also vital because it determines the ability of the wool to withstand vigorous manufacturing and cleaning.
Note that the staple length dramatically contributes to the fleece’s weight. Wool with breaks in its fibers or tender wool significantly diminishes the fleece value.
A wool’s whiteness affects its appearance and can interfere with its dye-accepting ability and combing process. Off-white or white wool can accept more dye varieties in making different fabrics.
The commodity market regards dark-fibered wool as undesirable since colored fibers can’t accept dye. Conversely, most niche markets value colored fibers since many weavers and hand spinners like natural colors better.
Wool quality is determined based on the above-discussed factors, so consider them when evaluating wool grade and quality. Nonetheless, the best wool is very fine and super strong, with excellent felting properties and good elasticity. Also, keep in mind that some sheep breeds, like the Merino, have more valuable wool compared to others.