Does merino wool shrink?

31 August 2024

In answer to the question of does merino wool shrink when washed, the answer is yes - it can do, if the care instructions on the label aren't followed correctly. Having your favourite merino garment appear out of the wash looking damaged or mis-shapen can be truly disappointing, but why does wool shrink when washed at high temperatures, and how can you avoid it?

Merino wool is made from the fleece of the merino sheep, native to the precipitous wilderness of New Zealand. This lightweight wool has become world-renowned for its fine, soft fibres which offer natural breathability, temperature regulation and moisture management in all seasons. The hard-working wool can feel softer and more resilient than standard sheep's wool, but as a natural product it is still at risk of shrinking when it's not correctly washed, dried or cared for. This article looks at why does wool shrink, and how to prevent your merino separates from shrinking in the wash.

How does merino wool shrink?

Merino wool is a natural fibre which is an ideal choice for hard-working base layers, mid layers and outer layers, helping you to stay dry and cool in summer and warm and cosy in the winter. Famous for its elasticity, strength and resilience, merino is a versatile material that can be easier to care for than some other delicate wool fabrics, such as cashmere.

However, exposure to hot water, tumble drying, improper handling and harsh chemicals can affect the natural fibres. Merino wool fibres' greatest enemies are extreme heat, bleach, and friction or damage during washing. High temperatures from washing machines and tumble driers can cause the fibres to expand and rapidly contract when they dry, causing shrinkage. Using a very fast spin cycle, and a non-wool-friendly detergent, can also make fibres mis-shapen and damaged over time. Instead, you can care for your icebreaker items by washing them on a cool setting, using a delicate spin cycle, avoiding fabric softener or harsh detergent and air drying your items.

 

How to prevent merino wool from shrinking

Why does wool shrink when washed is a common question when it comes to wanting to care for your clothing. Merino wool has some natural resilience to shrinkage, but it's essential to always follow the care instructions on each garment's label to keep your clothing looking - and performing - at its best.

To avoid shrinking your merino wool, try to avoid extreme heat, over-agitation and certain chemicals. Washing merino wool in the correct way can help it last longer and maintain its shape by:

• Washing in cool or lukewarm water - check your care label for instructions, but most icebreaker clothing can be put in the washing machine with similar colours. Secure any zips or accessories that could damage the material.

 

• Selecting a delicate washing cycle - agitation of the fibres can lead to shrinkage, so choose a washing machine cycle with 500 revs per minute or less.

 

• Using a wool-friendly detergent - avoid bleach-based products and opt for gentle wool-safe formulas. Skip the fabric softener which can damage the wool.

 

• Air drying naturally - refer to your garment's care label for drying instructions. Avoid putting your merino wool in the tumble dryer. We recommend air drying your garments in the shade and airing out between washes to get the most out of merino wool's natural odour resistance.

 

Can you reverse merino wool shrinkage?

It can sometimes be possible to reverse wool shrinkage, though results are not guaranteed. It's better to follow the care instructions carefully to keep your favourite items in-shape, without the risk of shrinkage.




If accidents have happened though, or if your item managed to sneak into another wash cycle by mistake, you can try unshrinking merino wool by using the 'soak, condition, re-shape' method, before washing your items on a cool, gentle cycle once again.

 

Does merino wool shrink when washed? - Summary

If you're wondering why does wool shrink in the wash, the reason is that the delicate natural fibres can expand when exposed to intense heat, and rapidly contract when it cools, causing your clothing to shrink or become mis-shapen. Merino wool is known to be resilient and comfortable when it's being worn, but proper care during washing and drying is essential to avoid shrinkage and unwanted damage. Keeping your merino well cared-for will help it to last longer and perform at its best, so you can enjoy the great outdoors and achieve your activity goals.




Shop our merino wool range today and discover the difference merino can make to your exercise routine and day-to-day wear throughout the year.

 

Does merino wool shrink - FAQ

 

How much can merino wool shrink?

When following the garment care label, it's unlikely that your merino wool items will shrink significantly. Always wash in cool water, on a gentle cycle, and avoid tumble drying to stop shrinkage and keep your items looking their best.

 

Should I size up or down for merino wool?

When choosing your new icebreaker items, we recommend selecting your usual size. Our sizes come in slim, regular or relaxed fit, depending on the look and feel you're after. When creating a layering system using your icebreaker separates, we recommend sizing up if you're between sizes. 

 

Why did my merino wool shrink?

Machine washing on a hot cycle, over-agitating fibres with a rapid spin cycle, using harsh detergents and putting items in a tumble dryer can all lead to merino wool shrinking. To avoid shrinkage, always wash on a gentle cool cycle and air dry naturally as per the care label.

 

Is merino wool supposed to be tight?

Although you may want your activewear to be form-fitting, icebreaker's merino wool comes in a selection of sizes and fits. It's next-to-skin softness means it'll still stay comfortable if it's a slim fit, but for base layers we recommend leaving some room for effective air circulation and moisture management.

 

How many sizes will wool shrink?

Different ways of washing and drying natural wool, depending on the wool type and method used, can lead to different shrinkage levels. There's no guaranteed way to shrink wool to certain sizes, so it's best to select your usual size and follow the garment's care label to maintain its form.