How A Yarn’s Characteristics Affect Your Knit Fabric


That beautiful ball of yarn goes through many transformations before you find it in your hands, wanting to turn it into something amazing. Everything that goes into yarn production, from the natural or synthetic fibers it’s made of, how its dyed, spun, twisted, and wound into a ball affects the fabric you’re knitting. So it goes, it’s inevitable that a few things will go wrong. Aghast, your socks keep falling down and bunching up in your shoes, or your sweater stretched two sizes in length. This post delves into the characteristics of that coveted ball of yarn, and how they affect the knit fabric. With a better understanding of how yarn’s characteristics affects the knit fabric, it is possible to match “the right yarn” to “the right project”.

Note: This post expands upon the information given in my previous posts, including: Fiber Properties That Can Be Your Friend Or Foe, My Love Affair With Wool, It’s All About The Yarn, The Pros And Cons Of Knitting With Cotton, The Ultimate Summer Yarn – Linen, How To Buy Yarn For A Pattern: Substituting One Yarn Brand For Another, and What All Knitters Know: Knit Fabrics Have The Market Cornered In Pattern Stitch Variety.


The foundation of any yarn is the fibers it’s composed of. Fibers are classified into two groups: 1. natural, consisting of animal (protein) and plant (cellulose) fibers;  2. manufactured, consisting of cellulose based fibers, synthetic fibers, and metallic fibers. Blends are combinations of different types of natural and/or manufactured fibers. 


Here’s a refresher of important fiber properties I’ll be referring to in this post.




  • wool is the hair fiber from sheep and is the oldest and most popular fiber to knit with. There are many breeds of sheep producing a variety of fibers ranging from fine to coarse. The most luxurious and soft, fine fibers come from breeds such as Merino. Coarser hair fibers may not feel soft, but wear far better than finer wool, particularly where abrasion is an issue.
  • “hygroscopic” – a property unique to wool. Wool absorbs up to 1/3 of its weight in moisture, while still feeling warm and dry on the skin. It’s cool in summer and warm in winter. I think it’s by far the best fiber for outdoor garments and accessories.
  • extremely high resiliency and elasticity. You can “stretch” wool fabric and it recovers to its original shape.
  • the natural “crimp” or wave to wool fibers helps them absorb moisture and trap air, making fabric warm.
  • for almost any project, you can’t go wrong knitting with wool. It is the most popular fiber to knit for its many advantages, including: the way it glides on the needles; elasticity; great stitch definition; the finer weights are perfect for close fitting garments and Fair Isle patterns; the best yarn for socks; longevity; durability; breathability; warm and cool to wear.

Felted Wool vs. Superwash Wool

  • felting is a term describing the shrinkage of animal hair fibers, particularly wool. The cause of felting is due to the scales along the surface of the wool fiber or any hair fiber. (Not only do scales cause felting, but they help hold the fibers together). When these scales are exposed to heat, agitation, and moisture, the fibers entangle together forming a dense, matted fabric. This is why most wool knits are hand washed, so they don’t shrink.
  • superwash wool is a treatment applied to wool to eliminate the scales, rendering wool machine washable. A potential drawback to the superwash process is stretching. Beware of dramatic stretching with some brands. I’ve experienced this, and I’ve found the best superwash wool yarns are the fine weights used for projects like socks and shawls.


  • two different types of alpaca: Suri with long silky fibers, and Huacaya, denser fibers with more crimp. Most of the hand knitting yarns come from Huacaya alpaca.
  • high strength, producing long wearing fabrics.
  • similar moisture properties as wool.
  • alpaca fiber has fewer scales than wool, so it’s more lustrous.
  • doesn’t felt as easily as wool.
  • dyeing is not necessary. The fibers can be left in their natural state, as the fleece comes in more than 22 different colors.
  • consider touch, drape, and warmth when choosing a project.
  • alpaca is very warm, much warmer than wool. I once owned a 100% alpaca coat that was so hot, I always had to remove it when shopping. Bulky 100% alpaca can be very heavy and warm, so is not the best choice for garments.
  • not as elastic as wool, so using a rib pattern stitch will be more decorative than stretchy.
  • produces a dense, relaxed fabric that drapes.
  • great for projects next to the skin.
  • superfine alpaca is a better choice for garments. It will be softer and lighter weight than the coarser grades.
  • a subtle textured stitch like seed stitch works well, but cables or heavier stitch patterns can increase the weight of the fabric.


  • comes from the fleece of Angora goats. Kid mohair is the hair from the first two shearings of young goats. The fiber size increases with the age of the goat, so a young goat has fine, silky hairs. An older goat’s hairs are thick and coarse; more appropriate for products like carpets and outerwear.
  • mohair is durable, light weight and warm, but is less resilient than wool. When people think of mohair they think of the most common format, brushed, fluffy stuff. Pure, unbrushed mohair sheds or leaves a lot of fuzz behind. This is often an undesirable characteristic. It is best blended and is often found along with wool and nylon. Silk and mohair is another great blend. Rowan yarns makes a beautiful silk and mohair yarn called Kidsilk Haze.
  • knitters may find yarn with a large percentage of mohair difficult to work with; the long fibers entangle, making it almost impossible to unravel. The fluffiness of the yarn also hides a highly textured pattern; beware of detailed stitches.


  • a variety of moths produce silk; the most common is Bombyx mori. Silk cocoons produce fine, lustrous filaments in one continuous strand. Silk is the only natural fiber that comes in filament form.
  • wild silkworms produce a coarse fiber with an irregular surface that is less lustrous (tussah silk).
  • has a smooth, slippery surface, lacking bounce or body. Much less elastic than wool.
  • silk is a great insulator or warm; that’s why you often see silk long underwear.
  • has a relaxed drape and reflective qualities to the fabric. Great yarn choice for tops and shawls.
  • rib patterns have no stretch, so 100% silk is not the best choice for items such as socks. For this reason, silk is often blended with more durable, elastic fibers like wool. The silk in blends still adds the sheen and drape.

Note: Blended yarns will add the best properties of each fiber it’s composed of. The amount of each fiber is important and determines the performance of the yarn.


  • less popular in hand knitting yarns.
  • fiber length is most important to the quality of cotton – long staple fibers as in Pima, Egyptian, and Sea Island cotton have better fiber properties.
  • high strength to cotton fibers, and stronger when wet. Best for warm weather climates because it’s highly absorbent, and releases quickly through evaporation. It doesn’t hold heat close to the body.
  • generally, the tighter the spin, the firmer the yarn, giving longer wear.
  • looser the spin, the softer the yarn, but more likely to pill and wear more quickly.
  • longevity is not like wool, wears out much sooner.
  • inelastic and not resilient like wool, so it may stretch over time. However, it typically goes back to shape after washing.
  • ribbing alone will not draw the knitting in. Blended with a stretchy fiber will alleviate this problem. The way cotton is spun also affects elasticity; multiple plies and twisted types are more bouncy.
  • textured stitches will work but keep in mind the weight of the fabric. Lots of cables and bobbles will make the fabric heavy.
  • stitch definition and colorwork is best with simple pattern stitches.
  • mercerization is a chemical finish that adds luster and improves cotton’s dyeing properties. Mercerized cotton is stronger than regular cotton, and less prone to shrinkage. This type of cotton is my favorite for its sheen, durability, and beautiful colors.


  • extremely durable, more so than cotton.
  • highly absorbent and wicks moisture away from the skin – breathable. A great warm weather fabric.
  • lacks elasticity – absolutely no “spring” to this yarn. Rib stitches in borders are not elastic.
  • stockinette stitch and garter stitch are not good pattern choices, unless combined with other pattern stitches. Garter stitch on its own will drape too much. Textured and lace patterns are most suitable.
  • for socks think again. If you want beautiful drape and durability, linen is perfect for summer tops, shawls, or pieces that don’t need to hold their shape.
  • easily laundered and almost looks better with age, becoming softer with each successive washing.


  • comes from cellulose pulp of the bamboo stalk.
  • highly absorbent and takes dye well.
  • can be processed to create a silky, soft yarn that drapes. Although it drapes well, consider the weight of the project, because 100% bamboo will drape so much it elongates. I once made a beautiful detailed jacket out of bamboo that stretched so much I couldn’t wear it. Wool or a blend would have been the better yarn choice. Choose projects wisely; simple summer tops, lacy scarves.



  • nylon is a generic name for one of the fibers found in the fiber group called polyamides. You may notice the words polyamid, polyamide or polymid on yarn labels; most likely they are referring to nylon.
  • major advantage of nylon is its strength. It’s one of the strongest textile fibers, and is commonly used in blended yarns to reinforce them. Wool with a small percentage of nylon is a common blend found in many sock yarns. Nylon is also used as a binder thread in brushed mohair, and in novelty yarns such as eyelash yarn.
  • very low absorption of moisture.
  • pilling is a significant problem because it is so strong, the fibers get tangled and don’t break off the surface of the fabric.
  • the best yarns blends should contain a low percentage of nylon (40% or less), otherwise it’s worst qualities will negate it’s advantages.


  • the first production of acrylic in the 1950s was as a replacement for wool; less expensive and washable.
  • acrylic is heat sensitive and stretches when wet.
  • prone to severe pilling and static.
  • the manufacturing process of brushing is used to mimic the look of mohair, but does not have mohair’s properties.
  • it’s best applications are as novelty yarns, such as fake fur and other bulky textured yarns. Small percentages of acrylic blended with cotton and wool adds more strength for these short staple fibers.


Amongst knitters, there is varied appeal for synthetics. A “synthetic fiber” is a result of chemical synthesis, and is not environmentally friendly. Although they mimic natural fibers, their underlying structure and properties are very different. Synthetics are generally less expensive and easier to care for, but as a rule a pure synthetic absorbs very little moisture, feels hot and clammy, and doesn’t breathe on the wearer. They can be uncomfortable in warm climates. The lack of moisture absorption causes static electricity. Static also acts as a magnet for dust and dirt; frequent washing is a must. They are prone to severe pilling and synthetic fabrics look worn much sooner than fabrics made of natural fibers. They certainly do not have the longevity of a luxurious natural fiber. Synthetics perform best when blended in small percentages with natural fibers; when their best properties are taken advantage of, while the natural fibers alleviate a synthetic’s worst properties.

I avoid synthetics, except for a small percentage of nylon in sock yarns and fake fur. I find the pilling issue one of their greatest drawbacks. The difference between natural and synthetic fibers is the pills can most often be removed from a natural fiber fabric, whereas the strength of a synthetic doesn’t allow the entangled fibers to break away. The many hours spent knitting a complex pattern with a synthetic will be wasted, as your project will look like a mass of pill balls in no time. Really think about the function of your project, the use of complex stitch patterns, and the hours spent knitting when deciding on whether or not to use a synthetic.



Spinning the fibers into yarn requires a certain amount of twist so the fibers adhere to each other. The amount of twist affects a yarn’s performance. In general, the longer the individual fibers, the less twist needed to hold them together. There are exceptions, but the greater the twist, the higher the strength and durability. Loosely spun yarns tend to pill, and garments made from them may stretch.


The number of plies or strands of yarn twisted around each other affects strength and durability. Yarns are classified into two categories: simple yarns and novelty (specialty) yarns. Simple yarns consist of: a single ply yarn or a single fiber twisted into one continuous strand; 2 or more singles twisted together into a plied yarn (eg. 4-ply yarn means 4 single fibers twisted together); and 2 or more plies twisted together into a cord (eg. 4-2ply cord means 4 groups of 2 plies forming the cord). The degree of twist used to form plies can range from low to high. The number of plies does not dictate the diameter of the yarn strand or weight. A tightly twisted 4-ply yarn will wear better than a low twist single ply yarn.

Novelty yarns are created by special spinning, twisting or combining these processes. This yarn category includes:

Textured Yarns

  • these consist of hairy and tweedy types.
  • affect the fit and ease of garments.
  • complex patterning may be buried by highly textured and hairy yarn types.

Smooth/Silky/Slippery Yarns

  • fall or drape with gravity.
  • don’t add bulk, but can stretch.


The number one motivator for a purchase is the “color” of the yarn. Dyeing yarn is simply the application of color by either natural (organic) or synthetic dyes. Dyes are chemical compounds dissolved in water or liquid, so they penetrate the fibers. Dyes are chosen based on their compatibility with fibers. For example, a dye formula used to color nylon is different from the dye used to color wool fibers. Each fiber responds differently when colored. Some fibers like silk and cotton generously soak up color to create brilliant, lustrous effects. Hand knitting yarns are dyed in either the fiber form (prior to spinning) or in the yarn format (hanks).

Because of the popularity of hand dyed and hand painted yarns, I want to disuss these terms. Hand dyed yarns tend to be driven by a single person in small factory settings, producing personal and special yarn collections. Hand painted yarns use various techniques of manually applying dye to the yarn in a “painterly” fashion (not dunked into dye pots) to achieve a rainbow of color.

Kettle dyed yarn is an advanced hand dyeing technique for coloring yarn that involves manipulating the dye in pots or vats in small batches to produce tonal effects. A common “look” is a subtle gradation of one color or lighter and darker areas of one color. Popular brands using this method are Malabrigo and Manos del Uruguay. Hand dyeing in kettles have no true dye lots; even though the hanks are dyed in batches; each hank is still a little different.

Hand dyeing requires skill and an understanding of dye chemistry. Truly good hand dyed yarn looks beautiful on the skein, but equally knits into a beautiful cohesive work of color.

In large scale operations, the following terms create different effects when knit. Space dyeing gives yarn a multi-colored effect. A skein of space dyed yarn consists of two or more different colors that are repeated across the length of the yarn strand. The effect is collage-like or uneven horizontal stripes. It is possible to produce space dyed yarns at home, but the effect is less precise.

Variegated yarn is dyed with more than one color. There is a wide selection of variegated yarns including: heather or tweed containing yarn flecks of different colored fibers; ombre with light and dark shades of a single color; multi-colored with two or more distinct hues; self-striping with lengths of color that automatically create stripes in the knit fabric; and marled, made from strands of different colored yarns twisted together.

The effects of variegated yarn vary depending on the technique, pattern stitches used, and the frequency of the color changes. These effects include “flashing” (lightning bolt) and “pooling” (patchy). With any yarn dyed in multiple colors, you run the risk of “pooling”, where the specific colors in the yarn repeat occur at just the right intervals on the fabric, stacking on top of each other to form “pools” or “patches” of color. Some yarn manufacturers deliberately do this or plan color pooling, like self-patterning sock yarn.

Pooling has varied appeal amongst knitters because it can look awkward and splotchy. To diminish the pooling effect with hand dyed yarns, some knitters suggest knitting with two skeins simultaneously; by knitting two rows from one skein, then two rows from the other. Color pooling occurrs less often with hand painted yarns.


Dye lot numbers are stamped on yarn bands. Yarn is dyed in batches, so it’s not uncommon for the same color to vary from one dye lot to another. Differences between dye lots can be very obvious when knitting an item in a solid color. You will notice a line where a change in dye lots occur. For this reason it’s a good rule of thumb to buy all yarn from the same dye lot or batch. Sometimes it’s not always possible to get them the same, but one solution is to introduce a new dye lot in small doses; alternating a few rows of the old yarn with a few rows of new yarn beginning early in the project.

Hand dyed and hand painted yarn producers may not bother with dye lots as the yarn works its magic on the needles. It’s all about the beauty of the color mix.


It’s not uncommon for brightly colored yarns and dark shades to release a small amount of dye in the first few washings. Generally, you won’t see changes in the overall color of a knit. A final rinse with a small amount of vinegar in the water can stabilize the dye, if you notice excessive bleeding.


In my previous posts on substitution, I mentioned that the amount of yarn in meters/yards is key to choosing a substitute. But you can’t substitute any yarn even with the same yardage. It’s also important to choose a yarn with a similar fiber content as the one used in the original design. When thinking about replacing one fiber type for another, consider the fiber’s properties and how it may affect your project. For example, if you replaced wool with cotton in a design knit in cables and textured stitches, you will notice differences in the end product. Cotton is inelastic and tends to stretch, is heavy, hangs differently from wool, and doesn’t wear as well.

The yarn’s structure contributes much to the texture of the knit fabric. Remember the character of the yarn. Cotton and silk yarns stretch, and change shape when worn, while wool retains its original shape. Tapes and slippery yarns give dimension to the fabric, while mohair is light and airy. Tweeds and variegated yarns provide an allover color dance, so substituting a solid, plain yarn will make the fabric look ordinary. Lastly, complex stitchery may be buried with highly textured yarns.


“A swatch is your best friend”

Every knit creation stems from its main material – the yarn. I can give you lots of information, but experiencing first hand how a yarn affects knit fabric is the only way to learn what a yarn can do for your project. Making many projects from the different fibers and yarn types helps you better understand their properties. Don’t avoid making swatches; a swatch of a coveted ball of yarn speaks volumes. Afteral, your goal is to match “the right yarn” to “the right project”. And it’s possible to do so. There is no “wrong” yarn, only a “wrong” choice.