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Does Merino Wool Shrink When Washed? (How To Avoid It!)




Merino wool is a remarkable material made from the wool of Australian and New Zealand merino sheep. Not only is the wool incredibly soft and durable, but it is also known for being resistant to odor, breathable, versatile, and exceptionally comfortable.

These staggering properties of merino wool, along with its many other benefits, make it a perfect material for warm and cool weather.

But since you are here, you probably know all the benefits of merino wool already. So let’s get to the point!

Modern Merino wool garment has exceptionally fine fibers with a stretchy structure that keeps their shape even after multiple rounds of washing. However, make sure to use low temperatures, a suitable detergent, slow centrifugation, and air drying for the best result.

Although much of the advice on merino wool in this article will also apply to other fine wools such as cashmere, vicuna, or angora wool. But be sure to know the differences between the wool types, and be extra careful when washing cashmere wool.

Plus, merino wool does not damage the environment as much as synthetic fibers. After all, it comes from a natural resource.

No wonder merino wool is the preferred choice for hikers and outdoor lovers.

But does merino wool shrink when washed? And what kind of care should you provide to your merino socks and sweaters?

Does merino wool shrink in the washer?

One of the best things about merino wool is that even if you wash your garments in the washing machine, they won’t shrink easily.

To start with, it is a good idea to turn your garments inside out before tossing them inside the machine.

Additionally, avoid washing them with hot water, and place your washer in a gentle cycle setting.

Finally, contrary to common beliefs, it is best not to use any softener or bleach.

Essentially, nothing will happen to your merino wool sweaters and socks if you place them in your washer as long as you don’t go too high on the temperature and centrifugation settings.

Today, most washing machines wash at lower temperatures, so all you have to do is follow the same procedure you would do with any other type of clothing.

We recommend washing merino wool at no higher than 86°F (30°C) for the best result.

For best results, you might want to use the hand-wash setting on your machine and a wool-friendly laundry detergent.

However, if your laundry machine does not offer a hand washing program, do not worry. Just ensure you select any low-temperature setting with no higher than 1200 RPM centrifugation to reduce any damage to the fibers.

Most merino garments do just fine with the “standard” settings. Still, as a rule of thumb, you should always read the instructions that come with the clothing, as different pieces might require different levels of care.

However, you can generally rest assured the size of your merino wool clothes will not change.

Watch this short video with instructions on how to wash your merino wool garment in the best way possible.

Does merino wool shrink when washed in cold water?

No, not to a significant extend. That is why the safest way to wash merino wool is in cold water by hand.

If you follow the instructions on your merino wool garment and wash it at low temperatures, you will never have to worry about shrinkage.

However, there are a couple of extra tips you might want to follow to eliminate any possibility of your clothes changing size after being washed.

First, it is always a good idea to use a mild detergent specifically designed for washing wool. This will help to protect the fibers and keep them from shrinking or becoming damaged.

Another tip is to avoid wringing or twisting your merino wool garment after washing. Instead, gently squeeze out any excess water and lay the garment flat to dry. This will help to prevent shrinkage and keep your clothes looking their best.

Additionally, you may want to avoid drying your merino wool garment in the dryer. The heat from the dryer can cause wool to shrink, so it is best to air dry your clothes instead.

Overall, washing your merino wool garment in cold water and following the care instructions on the label should help to prevent shrinkage and keep your clothes looking great.

Does merino shrink in the dryer?

Indeed, the high temperatures from the dryer can cause the shrinking and pilling of your merino wool garment.

While exceptionally durable, merino wool’s fibers do not stand high temperatures and they will start pilling and shrinking if dried at high temperatures too frequently.

The best tip to keep your woolen clothes in optimal condition is to avoid the dryer if you can. This is somewhat opposite to other outdoor clothing such as membrane and puffer down jackets, that do need the drier to open up the pores and separate the down.

The truth is that the best way to dry this material is air drying. Just leave your garments hanging to allow the water to dry out without exposing the fibers to excess heat.

However, if you must use the dryer, there are a few things you can do to minimize shrinkage and protect your merino wool garments.

First, use the lowest heat setting on your dryer and avoid over-drying your clothes. This will help to prevent the heat from damaging the fibers and causing shrinkage.

Another tip is to add a few wool dryer balls to your dryer along with your merino wool garment. These balls will help to fluff up the fibers and keep them from becoming matted or tangled, which can cause shrinkage. Just like you would do when drying a puffer down jacket!

Additionally, you can use a fabric softener sheet in the dryer to help reduce static and keep the fibers from clinging together. This will help to prevent shrinkage and keep your clothes looking their best.

Overall, air drying is the best way to dry your merino wool garments, but if you must use the dryer, following these tips will help to minimize shrinkage and protect your clothes.

Can you wash merino wool too much?

Yes! If you wash your merino too much or under too harsh conditions, you risk the following:

1. Shrinking, as discussed above. 

2. Pilling and shedding.

3. Loss of anti-bacterial and anti-odor properties due to loss of lanolin.

Lanolin is an oily compound secreted by the sheep to keep its wool dry and free of bacteria. Whereas there is only a small amount of lanolin left in processed merino wool, most merino wool, as well as other fine wool products, do contain lanolin and

How often should you wash merino wool?

You should wash your merino wool clothes depending on how often you wear them and for what purpose.

If you wear it every day, or for strenuous activities, it should of course we wash more often. It also depends on whether the garment has direct contact with your skin, in which case it would be necessary to increase the washing frequency even further.

A merino wool sweater, for example, does not need to be washed as often as merino wool underwear. 

While merino wool is naturally antibacterial and therefore smells less, there are limits to how much it can handle and it is important to let it dry out and air through as often as possible. This will deprive the bacteria of essential water and therefore prevent them from growing and producing odors.

In general, to avoid having problems with your merino wool garments, we recommend that you always wash your new merino wool clothes after the first three uses.

This way, you will make sure to remove any residual chemicals (such as formaldehyde and chromium) used in the manufacturing process that may cause skin irritations or allergies, as well as avoid the build-up of bacteria.

An appropriate washing frequency ensures that you never overpower the natural antibacterial properties of the wool.

We recommend this because of the durability and the breathable quality of the material, which allows most users to go around three or four days before washing their merino wool clothes, but it of course depends on your use and preference for cleanliness.

But remember, you should always read the labels and specifics of your clothes, especially when it comes to wool, as the washing settings and frequency depend on the specific garment.

Can you wash merino wool with shampoo?

Merino wool can be washed with a wide variety of soaps, but it will last longer with attentive care.

You can wash your merino wool sweater with shampoo, but using use on without too many additives. Preferably one made for the purpose.

The reason for choosing mild detergents without harsh chemicals and enzymes is to preserve the colors and fine fibers of the material. Choose shampoos and soaps specific for wool, cashmere, or silk if you want to stay on the safe side.

If your merino wool item just got stained, you might want to consider applying a spot treatment to save your wool from the wear and tear of washing.

If you just have a local stain, there is no need to use the washing machine. Avoiding machine washing will limit the stress on the fibers and make the overall clothing piece last longer.

Apply some soap wherever needed and work gently around the stained area. Remove the soap with water and go over it with a wet cloth.

How to avoid pilling of merino wool when washing?

One of the most annoying problems associated with wool is the phenomenon of “pilling”.

If the name doesn’t sound familiar, don’t worry. “Pilling” refers to the formation of small balls of fiber on the surface of wool clothes, which looks bad and can be quite annoying!

Wool pills when the wool fibers rub against each other or an external material that makes the fibers interlace. Pilling and shedding are generally less of a problem for the finer wools such as merino, cashmere, and vicuna, but it does happen with time.

A tip for maintaining the quality of your merino wool socks and sweaters is to wash them together with other soft fabrics.

Avoid washing merino wool with rough-surfaced clothing such as cotton. Especially denim will wear down your merino wool faster.

The milder a washing program you use, the less piling will take place. Washing by hand with minimal soap and air drying is the best way to avoid piling!

Also, it is best to turn your garment inside out when washing to avoid piling on the outside where it is more easily noticed.

Generally, the less wear and tear when in use and the less washing, the less pilling you will experience, but a minimum of careful washing also helps get rid of the loose fibers that cause pilling in the first place.

I have met experts in the wool industry who recommend freezing your merino wool garment before washing to shorten the fibers, which in turn intermingle less and results in less pilling!

I tried it recently and it does seem to reduce pilling, but I will need to do a few more washes to be certain.

How much does merino wool stretch?

One of the few reasons why your wool garments might stretch or shrink will be due to mismanagement.

For instance, if you expose your pieces to bleach or decide to tumble dry them, you might cause damage to the fibers. That is especially true if you wash your wool pieces too frequently.

In general, merino wool tends to shrink rather than stretch. However, if you forget to remove excess water before air-drying your merino clothes, you may cause them to stretch out from the added weight.

Just as cashmere wool, merino wool is naturally stretchy, and it can extend up to 30% of its length without breaking.

Be careful about this property because it is never comfortable to wear clothes that have changed their sizes!

On the other hand, the level of shrinkage usually depends on how badly you are taking care of the pieces.

If you often wash them with softeners and dry them at high temperatures, you can expect your merino wool clothes to shrink down up to two sizes.

How do you shrink merino wool on purpose?

So maybe you actually want to shrink your piece of merino wool because it has become too large or you did not manage to get the right size.

No problem! Definitely possible, but it is important to do it in a controlled fashion!

As you probably know, merino wool can shrink, but you have to be careful in the process as you don’t want to damage the delicate fibers.

To shrink merino wool, ensure you dampen the garment. Doing so will help shrink it evenly. Then place it in a tumble dryer at medium heat, but keep an eye on it. As soon as you notice it’s shrunk enough, take your clothes out.

This way, you can reduce the size of your wool clothing by 1-2 sizes without damaging the structure.

How to unshrink merino wool?

If you shrunk your merino wool sweater by accident, here is some good news for you! You can (most likely) revert it to its original size, by following a few simple steps.

All you have to do is fill a tub or a sink with lukewarm water and add a good amount of conditioner. Of course, we recommend using a product specific to wool. However, you can use a regular hair conditioner too.

The keys to unshrinking a merino wool garment are moisture, movement, and moderate heat.

1. First of all, soak your sweater, socks or whatever item needs unshrinking.

2. Squeeze the item to allow the conditioner to penetrate the fibers.

3. After half an hour or so, take it out from the water, making sure you remove excess water as much as you can without squeezing the garment.  

4. Then, lay the piece of clothing flat on a towel. Now, it’s time to stretch the item.

5. Stretch the fibers in sections, incrementally and in stages, until the whole piece of clothing is completely dry.

Once you are satisfied with the reshaping process, wash the item one more time – and remember to use cold water and air-dry it!

While this method works fine, don’t expect miracles. Whereas you may be able to increase the size by 1-2 numbers following the steps above, it will never really be the same as the original as the wool fibers are likely damaged for good.

Can merino wool be dry cleaned?

You can dry clean merino wool as well as other fine wool types, but it can be a costly process. Check the label of your clothes. Unless it states “dry clean only.” you can use your washing machine, or even better, wash it by hand.

While it is possible to dry clean merino wool, it is not always the best option for several reasons. First, dry cleaning can be quite expensive, especially if you have multiple items of clothing that need to be cleaned. Additionally, the chemicals used in the dry cleaning process can be harsh and potentially damaging to your clothes.

Another reason to avoid dry cleaning your merino wool is that it is not always necessary. Unless your garment is labeled as “dry clean only,” you can safely wash it at home using a mild detergent and cold water. This will save you money and help to protect your clothes from damage.

If you do decide to dry clean your merino wool, it is important to choose a reputable dry cleaner and carefully follow their instructions. Be sure to let the dry cleaner know that your garment is made of merino wool, as they may have special care instructions for this type of fabric.

Overall, it is best to avoid dry cleaning your merino wool unless it is absolutely necessary. Washing it at home using cold water and a mild detergent is a more cost-effective and gentle way to clean this delicate fabric.


Does Smartwool Shrink?

Yes, Smartwool’s products will also shrink if washed too hot or dried at high temperatures in a tumble drier.

Smartwool is a brand of merino wool, so all the advice that applies to merino wool mentioned in this article also applies to garments made by Smartwool.

How to best wash merino wool socks?

The best way to wash merino wool socks is to turn them inside out and place them in the washing machine in a gentle setting. Also, it is preferable to wash them in cold water. Remember to air-dry your socks to ensure they keep their shape.

How to best wash a merino wool sweater?

You can wash merino wool sweaters in your washing machine or hand-wash them safely. It all depends on what you prefer. Just remember to turn the items inside out or use a laundry bag to reduce “pilling.”

Also, ensure you wash them with gentle detergents and avoid using softeners. If you are hand-washing, don’t forget to rinse your garments thoroughly before hanging them to dry.

Additionally, dry your merino wool sweaters laying flat in the shade. This will help preserve the shape and color of your items.

The Bottom Line

Merino wool is an astonishing material. Its softness, durability, and versatility make it appropriate for various purposes, especially outdoor activities.

If you take good care of your clothes, you can expect your garments to last long. While washing them is not a problem, you should be more careful with drying your merino clothes.

Avoid high temperatures and prefer air-drying, but do so before removing excess water to eliminate any chance of stretching.

Now you know how to both wash, shrink and un-shrink your merino wool clothes!

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