Does Merino Wool Pill? [Definitive Guide!]

Merino wool is renowned for its soft, lightweight warmth. But many merino wool garments seem prone to pilling—those annoying little balls of tangled fiber that can make clothing look old and worn.

If you’ve noticed your favorite merino sweater or leggings pilling after just a few wears, you’re not alone. The delicate fibers that lend merino its coveted softness also make it susceptible to pilling.

So, why does merino wool pill, and is there any way to prevent it? In this guide, I’ll share tips to prevent the pilling of Merino wool and make your Merino wool clothing last longer.

So, Why does Merino wool pill? Yes, merino wool can pill. The small balls of fibers known as pilling occur when the wool rubs against itself or other surfaces. This abrasion causes pilling most often in high-friction areas like the elbows, underarms, and collar. But quality merino with tight yarn twist pills less than other wools. Washing inside-out, using gentle detergent, and avoiding the dryer helps minimize pilling. Merino’s natural elasticity makes it resilient against pilling. Proper care and a pill remover tool can address any pilling issues.

Keep in mind that pilling doesn’t mean the garment is ruined! It may look messy but doesn’t affect the integrity or warmth of the fabric. Using a fabric shaver safely removes the pills and restores a smooth appearance.

Also Read: Does merino wool get holes

What Causes Pilling of Merino Wool?

Here are the following causes of Pilling of Merino wool:

1. Softer Merino Fibers Can Pill More

Merino sheep produce a very fine, soft wool that is prized for making clothing. The fineness of the fibers is what makes merino wool so soft and comfortable against the skin.

Fiber fineness refers to the thickness or diameter of the individual wool fibers. Finer fibers have a smaller diameter. Merino wool is known for having fibers that are 18-24 microns in diameter

The fine fibers of Merino wool have less surface area and are more fragile. So they can break easily from abrasion and entanglement.

Moreover, the fine fibers of Merino wool are loose enough to work their way out of the yarn structure and stick out from the fabric surface.

Pilling is most prominent in parts of a garment that receive the most abrasion – like elbows, shirt collars, underwear waistbands, and socks. The pills appear randomly in these high friction areas and can grow larger over time.

2. Short Staple Length

Staple length refers to the average length of the wool fibers when they are shorn from the sheep.

Merino sheep typically have a staple length between 60-100mm. However, there can be variation between different merino flocks.

Shorter staple lengths below 60mm are more problematic when it comes to pilling. This is because:

  • Shorter fibers are able to detach more easily from the yarn surface during wear and abrasion. Longer fibers stay anchored into the yarn structure better.
  • Shorter fibers can form pills faster. Longer fibers take more time and friction to tangle up.
  • Yarns made with shorter fibers have more fiber ends sticking out on the surface. These loose ends are the starting point for pilling.
  • Shorter fibers result in a less smooth and consistent yarn structure, with more potential snagging points across the surface.

Long staple wools like Blue-faced Leicester were recommended for pill resistance

So in summary, the shorter the merino wool staple length, the more prone the resulting garments will be to developing those pesky little fiber pills during wear.

3. Looser Knits and Weaves

Any garment can pill. But merino knits and woven fabrics with a looser construction tend to pill faster for a couple reasons:

  • More movement: When stitches or threads are spaced farther apart, there is more room for the yarn to shift and rub. This creates more opportunities for fibers to work loose and form pills. Tighter knits don’t move against each other as much, so there is less abrasion.
  • More exposed fibers: A loose knit has more fiber ends sticking out from the yarn. These loose ends readily catch on other fibers and fabrics, eventually tangling into pills. A tighter knit has fewer exposed fibers since more yarn is packed into each stitch.
  • Less structural integrity: Loosely spaced stitches or threads are only lightly interlocked. So the fabric is less resilient against the stresses of wear. It’s easier for fibers to pop free when the structure is flimsier. Densely knit or woven merino holds its shape better, preventing pills.

Factors that Worsen Pilling In Loose Merino Knits

These factors can exacerbate pilling in loose merino knits:

  • Friction: Areas that rub against the body or other surfaces pill the fastest. The friction works fibers loose. The inner thighs, underarms, and abdomen are common trouble spots.
  • Washing: Frequent washing accelerates pilling by increasing friction during the wash cycle. Agitation loosens fibers. Using a gentler cycle and washing less often can help.
  • Dryer heat: Tumbling in the dryer also creates friction. Air drying allows pills to form at a slower rate.
  • Lower quality yarn: Cheaper yarns with more short fibers and variability in the spun threads are more prone to pilling. Higher grades of merino with long, even fibers resist pilling better.
  • Tight fits: Merino pieces that cling to the body are prone to more fiber friction and pilling, especially during active wear.

3. Yarn Construction and Spinning Technique

Yarn construction and spinning techniques are two factors that can influence the pilling of merino wool.

Yarn construction refers to how the fibers are arranged and twisted together to form a yarn.

Spinning techniques refer to how the fibers are drawn out and twisted from a mass of raw material to form a yarn.

Different types of yarn construction and spinning techniques can affect the length, thickness, strength, elasticity, smoothness, and twist of the fibers in the yarn. These characteristics can determine how prone the yarn is to pilling.

Yarn construction

There are two main types of yarn construction: single-ply and multi-ply.

Single-ply yarns are made of one strand of fibers twisted together. Multi-ply yarns are made of two or more strands of fibers twisted together.

Single-ply yarns tend to pill more than multi-ply yarns because they have fewer twists and more loose ends that can break or fray easily.

Multi-ply yarns tend to pill less because they have more twists and fewer loose ends that can hold the fibers together more securely.

Spinning techniques

There are many different types of spinning techniques that can be used to produce merino wool yarns. Some of the most common ones are:

  • Ring spinning: This is a traditional method that uses a ring-shaped device to draw out and twist fibers into a fine and smooth yarn. Ring-spun yarns tend to pill less because they have longer and stronger fibers that are tightly twisted together.
  • Open-end spinning: This is a modern method that uses a rotor or an air jet to collect and twist fibers into a coarse and fuzzy yarn. Open-end spun yarns tend to pill more because they have shorter and weaker fibers that are loosely twisted together.
  • Worsted spinning: This is a method that involves combing the fibers before spinning them into a smooth and even yarn. Worsted-spun yarns tend to pill less because they have longer and finer fibers that are aligned in parallel.
  • Woolen spinning: This is a method that involves carding the fibers before spinning them into a fluffy and irregular yarn. Woolen-spun yarns tend to pill more because they have shorter and coarser fibers that are mixed in different directions.

Therefore, it is important to choose spinning techniques that produce longer, finer, stronger, smoother, and tighter fibers that are less likely to pill.

4. Merino Wool Blends, Especially with Nylon, Tend to Pill More

Merino wool blends are fabrics that combine merino wool with other types of fibers, such as cotton, silk, polyester, or nylon. Merino wool blends are used for various reasons, such as:

  • To improve the durability and strength of merino wool
  • To reduce the cost and increase the availability of merino wool
  • To add different colors, textures, or patterns to merino wool
  • To enhance the performance or functionality of merino wool

Must Read: Merino wool vs Synthetic Base Layers

Merino wool blends can have different proportions of merino wool and other fibers, depending on the desired characteristics of the fabric.

For example, a blend with a high percentage of merino wool (such as 80% or more) will have more of the benefits of merino wool, such as softness, warmth, breathability, and odor-resistance.

A blend with a low percentage of merino wool (such as 20% or less) will have more of the benefits of the other fiber, such as durability, affordability, or colorfastness.

Research shows that increasing nylon content in wool blends tends to cause more pilling.

Moreover, according to, any fiber that doesn’t absorb moisture, tends to pill more.

Nylon has a lower moisture absorption than merino wool. This means that nylon can repel water and sweat better than merino wool.

When merino absorbs moisture, the individual fibers swell and relax, which allows them to mesh together more cohesively. This helps “lock” the fibers into place within the yarn and fabric.

However, nylon is hydrophobic and repels water. The nylon fibers do not absorb any moisture and remain stiff and rigid when the merino fibers are relaxed and swollen. This creates a disconnect between the wet, relaxed merino and dry, rigid nylon.

With friction and abrasion, the nylon fibers are more likely to detach and pull free from the cohesive merino fibers rather than relaxing and meshing with them. The stiff, separated nylon fibers then easily tangle and matt together, forming pills on the fabric surface.

5. Improper Washing and Agitation

When you wash your clothes, friction and abrasion can happen between your clothes and the water, your clothes and the detergent, or your clothes and other clothes.

For example, if you use too much detergent or a harsh detergent, the detergent can damage the fibers of your merino wool clothes and cause pilling.

Or if you wash your merino wool clothes with other clothes that have zippers, buttons, or hooks, these items can snag on your merino wool clothes and cause pilling.

In addition, washing merino wool in hot water can also causes pilling. Hot water causes wool fibers to relax and become softer. This makes them more likely to untwist from the yarn and detach. Lukewarm or cool water is gentler on wool.

How agitation causes this?

  • The motion of the washing machine drum rubs clothing together. The longer the wash cycle, the more chances for pilling. Top-loading machines have more intense agitation than front-loaders. Handwashing rarely causes pilling because there is less friction.
  • Jamming too many garments in the machine presses them together tightly. This amplifies abrasion and pilling. Give clothing room to move around gently.

How about storing of Merino wool clothing?

When you store your clothes, friction and abrasion can happen between your clothes and the hangers, shelves, or drawers.

For example, if you hang your merino wool sweater on a wire hanger, the wire can cut into the fibers of your sweater and cause pilling.

Or if you fold your merino wool sweater and put it on a shelf with other sweaters, the sweaters can rub against each other and cause pilling.

Also Read: Does merino wool swell when wet

Does Merino Wool Pilling Affect Quality and Longevity?

Pilling is mainly a cosmetic issue rather than a structural one. It does not affect the performance or functionality of merino wool. Merino wool still retains its warmth, breathability, and odor-resistance even when it pills.

Some people may not mind pilling, as they think it adds character or charm to their clothes. Pilling gives the garment a softer, fuzzier texture over time. Some people enjoy this cozy, worn-in feel.

Others may find it annoying or embarrassing, as they think it makes their clothes look cheap or low-quality.

Pilling Is Just Superficial

What’s important to understand is that pilling only affects the surface of the garment, not the underlying structure. It’s just loose fibers rolling into balls. The yarn itself remains intact.

In fact, you can remove most pilling with a fabric shaver or pill comb. This instantly improves the appearance by getting rid of all those little bobbles.

So, pilling doesn’t damage the wool or shorten the lifespan of the garment. It’s purely a cosmetic issue. The integrity of the merino fibers is not compromised by pilling.

Advise Not to Equate Pilling With Quality

While pilling can be an annoyance with merino wool, it’s not detrimental to the quality or longevity of the fabric. It’s simply an aesthetic issue caused by surface fibers rolling into balls.

The integrity of the Merino wool itself is not compromised. With proper care and maintenance, merino garments can still deliver years of wear despite pilling. The key is not to let the pills accumulate and remove them regularly.

How to Prevent Pills in Merino Wool?

When it comes to keeping your merino fuzz-free, an ounce of prevention is worth a pound of cure. Here are some top tips to keep the pills away:

  • Hand wash gently: Skip the vigorous machine washing and opt for gentle hand washing instead. This eliminates the fiber abrasion that occurs in washing machines. Use a wool-specific detergent and lukewarm water.
  • Don’t over agitate: When hand washing, be very gentle. Avoid twisting, wringing, or scrubbing the fabric. Just a gentle soak and squeeze is all you need.
  • Use a laundry bag: Pop your wool sweater in a mesh laundry bag before machine washing. This prevents the fabric from rubbing against itself or other items.
  • Layer wisely: Avoid wearing delicate merino pieces directly over rough textured fabrics. An undershirt can create a barrier to reduce surface abrasion.
  • Watch for snags: Inspect sweaters before and after wear for any loose threads or snags and carefully snip them. This stops them from catching and pilling.
  • Fold properly: When putting away, fold neatly along the seams rather than bunching up the fabric.
  • Avoid Velcro & rough fabrics: Prevent contact between wool and Velcro, lace, sequins or anything abrasive that could catch on fibers.
  • Use lint rollers: For removing surface fuzz between wears, use a lint roller instead of brushes which can rub the fabric.

How to Remove Pills in Merino Wool?

Here are some safe DIY methods to polish your wool:

Sweater Stone Method

A sweater stone, sometimes called a fabric shaver, offers an easy way to swiftly remove pills and refresh wool.

These manual tools contain a coarse abrasive surface that simply shaves the pills away as you gently rub problem areas.

Look for stones with a fine grit specifically made for delicate wool. Always brush your garment after using a sweater stone to get rid of any shaved fuzz.

Razor/Shaver Method

For isolated pills, lightly skim the surface using a new disposable razor or electric shaver on the bare setting.

This cuts stray fibers with precision. Work carefully to avoid snagging or damaging the knit. Use short, gentle motions and don’t press too firmly. Finish by using a lint roller on the area.

Adhesive Method

An adhesive lint roller alone can remove some pills. For more stubborn pills, try this technique:

Wrap a piece of masking tape or scotch tape around your fingers, sticky side out. Firmly pat problem areas to pick up pills. Check progress and change the tape section as needed until pills are gone.

Hand Removal

For just a few pills, removing by hand works. Lightly pinch and roll individual pills between your thumb and finger. Avoid pulling which can stretch the knit. Work slowly to protect the fabric. This method takes patience but can be done anytime.

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