Alpaca Fiber Compared to Sheep Wool

While there are many varieties of sheep in the world, each bred for a specific purpose, this comparison is limited to evaluating alpaca fiber against “Merino” wool. Merino wool is associated with the ultimate in fine, soft, low-itch sheep wool. Merino sheep are bred for their fiber and not their meat. Merinos are bred all over the world, but primarily in Argentina, Australia, New Zealand, South Africa, and the western United States. 

Note 1: There are many kinds of sheep wool, just as there are many kinds of alpaca fiber. All have value. At this time, IAOBA sees no reason to attempt to force a breed standard on the North American alpaca. A “cookie cutter” approach would limit the numerous possibilities open to us for selective breeding for the great variety of fleece characteristics available. The emerging market for alpaca fiber should dictate value, just as the market for sheep wool has resulted in a wide variety of end-uses and products, each dependant upon unique fiber characteristics. Different breeds of sheep thrive in different geographic regions and produce widely varying end products. The same may hold true for alpacas.

Note 2: The evaluation of alpaca fiber vis-à-vis sheep wool will be the most extensive comparison we will make, as alpaca fiber and wool share a number of characteristics. The two are also natural companions for blending and, when done in the proper percentages, result in truly wonderful end products.

Class-One Wool

Merino sheep produce the “best” wool, in terms of fineness, softness, durability, memory, and strength. Wool is known for its ”memory,” which is the ability of fiber processed into textiles to bounce back to its original shape. Alpaca is often criticized for having inadequate memory and, as a result, is often blended with 6% to 20% wool to increase memory. 

Merino fiber is know for its high frequency of crimp. This high crimp frequency gives merino its “loft” and resultant insulating properties, making it very warm. Merino is also noted for its large number of cuticles (scales), which affect its spinning properties because the numerous scales grab each other easily. Merino frequently measures in the 16-22 micron range, with upwards of 30 crimps per inch. 

Elasticity and memory, although related, are not interchangeable terms. Elasticity is “give” – the ability to expand. Elasticity is a comparative measure of how far a fiber stretches. Memory is how well the fiber returns to its normal length. A rubber band has both elasticity and memory, while pulled taffy has elasticity, but little memory. Elasticity is partially affected by Huacaya crimp style. Crimp will provide some “give” in a yarn, but elasticity also depends on the twist of the yarn (1 ply, 2 ply, 3 ply, etc). Nylon, in the form of spandex, is sometimes added to alpaca to give it additional elasticity. Numerous options are available to create new fiber combinations and, therefore, new synergistic products.

Studies show that wool is 80% elastic, whereas alpaca is only 10% elastic. Alpaca, therefore, is not considered an elastic fiber. As a result, alpaca is often combined with wool, in amounts varying from 6% to 60 % of finished product, to give alpaca fabric added elasticity. According to one Australian Commonwealth Scientific and Research Organization (CSIRO) study, “Crimp in alpaca increases the ease of manufacture and can partially substitute for memory.” In finished fabric or products, memory refers to a fabric’s ability to return to its original state after being stretched. Sweaters that become baggy with wear or upon washing and that do not easily return to their original shape lack memory.

Suri and Huacaya fiber are not considered to have either significant elasticity or memory. While crimp structure from some highly crimped alpaca may remain in a woolen fabric, a significant percentage of the crimp will disappear in the manufacturing process. Nonetheless, in general, the more well defined the crimp going into the woolen process, the better for ease of processing and more loft in the end product.

Class-Two Wool

Class-two wool is somewhat inferior to Merino wool from a textile perspective. It is good wool but less expensive than Merino. It has a large number of scales, so it spins well. Unlike Merino, its scales have a sharper point on the three edges of the scale. This type of wool is often used for traditional Scottish and English sweaters. 

Class-Three Wool

These fibers have fewer scales and less crimp than the above two classes. Fewer scales make this fiber smoother and brighter. The smoother fiber reflects light better than fiber with numerous scales, which diffuse light.

The lower number of scales and the fewer crimps per inch in Class-three Wool decrease softness. It is also known that Suri fibers have fewer scales than Huacaya fiber, as well as little or no crimp. The smoother nature of Suri fiber lends itself to evaluation by breeders according to “luster,” while the equivalent term used to evaluate Huacaya fleece is “brightness.”

Note 3: The fiber industry in general uses the term “brightness” when referring to the various reflecting abilities of fiber. The term ”luster” is a breeder term applied exclusively to the Suri.

While luster appears as a deep “glow,” brightness is the result of light reflecting off irregular surfaces (crimp, for example). If you look at Suri fabric it does not have brightness like Huacaya, but something much more subtle and soft, which is what we call luster. Some studies state that Suri has been shown to have an oval hair shaft, which reflects more light than a cylindrical shape. Not true – fleeces with high SD’s exhibit more ovoid fibers but as density and fineness improve, the more cylindrical the fibers become. Oval fibers are reflective of a more unimproved or primitive fleece in either type of alpaca.

Note 4 – Class 3 wool is known to be less elastic and less resilient than Class-one or Class-two wool

Note 5: Suri does have larger scales that lay flatter than Huacaya fiber. The result is very similar to a mirror effect. Some Huacaya, however, can have just as much luster. It seems unfair to distinguish one from the other based on luster. In textiles, it doesn’t make that much difference. Most Suri will be processed in a worsted method, with tighter twist and weave that reduces handle, but adds drape. Therefore, loss of handle from larger Suri scales becomes a moot point. The luster of Suri, however, stays with the fabric, giving a completely unique and exotic ‘glow’ to the finished product.

Class-Four Wool

Class 4 fibers are long and coarse, with few scales and little crimp. They are, therefore, smooth and bright, but with very little elasticity, memory, or tensile strength.

 Note 6: Wool’s characteristics have been studied for centuries. It appears from the above classifications that fewer scales give wool fiber its brightness. Fewer scales also result in diminished memory. More scales contribute to greater strength and better memory. These facts should be kept in mind when investigating Huacaya and Suri fiber architectures.

Wool compared with alpaca:

• A major difference between alpaca and sheep wool is that wool contains lanolin, whereas alpaca does not. Lanolin is a wool grease that protects sheep fiber from the environment and that imparts a unique “odor.” Alpaca has no lanolin, making it odor-free. Generally, not all the lanolin is removed from wool during the scouring /washing process. Alpaca tends to stay cleaner than wool, because of this lack of lanolin; lanolin tends to attract and retain dust and small particles. While some people are allergic to lanolin, the skin rashes many people experience are from wearing inferior wool due to the “prickle factor” effect of 30-plus micron fiber, as it jabs into the skin (a direct result of the hooks from the scales on wool fibers). The prickle factor can also be caused from coarser hairs sticking out of fabric, interacting with the skin, and triggering pain receptors, resulting in irritation and itching. Lanolin is used in some cosmetics, salves, and other beneficial skin products.

• Because of its superior fiber tensile strength (its naturally strong internal structure), alpaca stands up to daily wear better than wool. Better tensile strength helps a garment resist holes, but tensile strength alone cannot prevent holes altogether. Fiber strength has two characteristic measurable functions: tensile strength and shear strength. Holes in socks are caused by failure of shear strength, due to repeated pressure perpendicular to the fiber. The principal reason for holes developing in the toes and heels of socks is the use of the wrong grade of fiber. Holes will develop both in poorly made alpaca socks and poorly made woolen socks. Holes in suits and dresses are caused by failures in tensile strength, where the force is parallel to the fiber. Again, properly processed alpaca fiber (no short or damaged fibers or second cuts) will resist these wear and tear issues better than most other fibers. Durability results from the use of the proper grade and length of fiber for the specific application. Quality control, therefore, is important to ensure that end products meet consumer expectations.

• When running your hand over fiber, alpaca will generally feel softer than wool of the same micron count. This softness is partly a result of the fact that the overlapping “scales” along the shafts of alpaca fibers protrude less (lie closer to the shaft) than on wool fibers. There are also fewer scales on alpaca fibers than on wool fiber and wool scales have “hooks” on them, while alpaca scales are soft, rounded, and leaf-like scale. Suri can feel even softer than Huacaya of the same micron count because Suri fibers have about 30% fewer scales than Huacaya fibers. The unilateral cortex and fewer scales of Suri fibers make them smoother to the touch and more lustrous, but a little harder to spin. 

It has been reported by Phan that the mean scale height of alpaca fibers that have fiber diameter greater than 19 μm is approximately 0.4 μm, while that of wool fiber of similar fineness is around 0.8 μm. Obviously such a scale profile will result in a smaller difference between the friction coefficients against-scale and with-scale for alpaca fibers than the corresponding difference for wool fibers It has been reported that the DFE (a technical term for friction metrics) is, on average, 0.20 for Huacaya alpaca, 0.16 for Suri alpaca, and 0.40 for sheep wool In addition, as the cuticle cell thickness reduces, the bending rigidity of the fiber may reduce For alpaca fiber, the mean scale frequency is greater than nine scale edges per 100 μm while wool fiber has four per 100 μm . This would result in a smoother surface for alpaca fiber than wool. Compared with the scale of wool, cashmere and alpaca fiber scales are thinner and denser.

• Wool is more likely to become heavy and saturated when wet, as it can absorb up to 35% of its weight in liquid. According to the Gaston Fiber College, alpaca wicks, but does not absorb.

• Some manufactures advertise that alpaca resists matting and pilling, and that only the finest alpaca fibers will pill. To our knowledge, however, this has not been substantiated and the quality of the fiber used, as well as the method of manufacturing, will have a substantial impact on whether or not a finished product has a tendency to pill or matt. 

• Alpaca is absolutely unique among fiber-producing animals in that it comes in the widest array of colors naturally available. The exact number of colors, however, is a matter of some debate. Peru cites 52 natural colors and Australia 12, while the United States identifies 22 individual colors. Research done at the University of Ohio suggests there are probably an infinite number of colors that appear to be expressed in alpaca fiber. However, the study identifies only three basic colors of alpaca fiber: black, white, and red (brownish/yellowish/reddish). These three basic colors combine in a wide variety of ways to visually create the many colors generally found on an alpaca color chart. One of the interesting implications of this study is that, if there are only three basic alpaca colors, then there are no true “gray" fibers. Silver gray and rose gray alpacas are a mixture of the three primary alpaca fiber colors.

• The key advantage to all this color choice in alpaca is that dyes are not needed to achieve a wide variety of color options for the consumer. Although alpaca, like wool, takes dye beautifully, most dyed colors are achieved through the use of chemical dyes that require the disposal of chemical waste, often toxic. These dyes add expense, an extra processing step, and a significant chemical waste stream, with its attendant environment impact. While natural, earth-friendly, non-toxic dyes can be used on alpaca, the addition of a dye step, particularly with the more expensive “natural” dyes, will increase final product costs. The alpaca, with its wide, natural array of color is a perfect fit for the growing interest in “living green” and this aspect of alpacas should be a marketing focus for North American breeders, who already possess the global edge in producing quality colored alpaca.

• Compared to sheep wool of comparable fineness and yield weight at shearing time, alpaca has been shown to produce a higher yield, and a greater percentage of fiber is retained after basic processing.

• Alpaca is, in general, more medullated (a distinctive feature of alpaca), generally grows a longer staple length, and is considerably stronger (tensile strength) than wool.

• Both alpaca and wool are susceptible to felting when agitated in water. Wool is sometimes pre-shrunk during processing.

• Wool scales are more hook-like than alpaca scales. This makes wool easier to felt (the hooks catch and hold on to each other), but also harsher to the hand than alpaca fiber of the same micron count.