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How to Wash Wool

How to Wash Wool

Maybe you’ve been hearing about wearing merino wool and are interested in adding some pieces to your wardrobe but are worried about wool care. Or maybe you’ve been a fan of wool for years but washing it always makes you nervous. Read on to discover the wonders of wool, and move past any nervousness about wool care!

Wool Benefits (and why to wear it!)

Merino wool is one of the most effective fibers in cold weather environments. It continues insulating even when wet (retaining around 75% of its insulating power), making it ideal for winter wear and especially active pursuits.

When you have been sweating and then take a break your body cools down and gets cold quickly; if you’re wearing wool you still want to keep your insulating layer handy but you’ll feel significantly more comfortable during the hot and cold of activity.

Wool fibers are actually generating heat when they’re drying! The kinks in the wool fiber trap warm air which helps keep you warm, unlike cotton which pulls heat from your body when it’s wet.

Wool is also hydrophilic (so it soaks up water but is able to soak up a lot before it feels wet) but oleophobic (so it doesn’t retain oils from your body). It won’t mold or mildew like other fibers, and it takes a lot to smell musty.

Wool is not just for winter either, wool will regulate your body temperature in cold or hot environments! In a hotter climate you’ll want to choose a lighter weight wool.

Wool is often labeled in microns (μm, one millionth of a meter), which is the diameter of a wool fiber. Merino wool in the 16-17.5μm range will be softer and lighter than merino wool in the 20-22μm range, but will also be less durable.

Anything under around 22μm will feel very soft to most people, but if you’re sensitive to wool try for under 18μm for maximum softness. Lower micron wool is best for underlayers and higher micron wool is better for insulating or outer layers. For comparison, a human hair is around 50-70μm.

Wool is also labeled in weights, ranging between 150 g/m^2 (grams per square meter) and 400 g/m^2. A “heavyweight” merino is going to be a good winter baselayer for harsh environments, “midweight” will be a good multiuse baselayer weight. “Lightweight” baselayers are good for nordic skiing, snowshoeing, or activities in milder temperatures.

While merino wool layers are not cheap, you really don’t need that many! Many synthetic layers can stink after just a wear or two, but merino layers stay fresh for many wears! Just a pair or two for everybody is enough to keep you cozy all winter long.

Types of Wool

Machine Washable Wool

Often referred to as “superwash” wool, this wool is often treated (bathed or coated) so that the fibers can withstand agitation without felting. Smartwool was one of the early pioneers of this easily washable wool, and no special washing techniques are required!

There are many other brands of easy care wool, including Iksplor, Chasing Windmills, Darn Tough, Meriwool, and Sloomb Raven baselayers. The Sloomb Raven layers are made of an interlock knit that actually responds better to being washed and dried (versus hand washing), and still stays soft and stretchy.

Machine washing can sometimes tighten up the fibers a little bit without felting (this has been our experience with the Sloomb Raven interlock), increasing durability. On the flipside, it can shorten the lives of some more delicate fibers (occasionally creating little pinholes), and all washers and dryers are going to be different. See our Baselayers Post and Socks post which include some of our favorite merino pieces!

Best practice or machine washing is to turn items inside out, and make sure that you’re not washing any delicates with things that have zippers or hard snaps, that will be more likely to cause holes in your woolies.

Hand Wash Wool

Hand washing wool is covered in detail below. You can really never go wrong washing your wool by hand, and in many cases it will prolong the life of your wool as the machine is tough on delicate clothes regardless of what setting is used. Hand washing and air drying is also more environmentally friendly, especially given that with wool you don’t have to wash very often.

When in doubt, hand wash your wool. If you’ve gotten the wool second hand, off Etsy, upcycled it, or just can’t read the care label, following our hand wash guidelines will get your wool cleaned up!

Two children outside with unzipped snowsuits showing wool long underwear underneath
Wearing NorthHaven woolies that we hand wash

Felting Wool

Why Wool Felts

One of the reasons that people are often afraid of buying and wearing wool is because it’s often not easy care. This is because it can felt.

Intentionally Felting Wool

Felting wool can be done intentionally. Wool cloth diaper covers are very effective (and so cozy!), and can be felted by hand to give maximum wetness protection in certain areas (the “wetzone”) and maintain stretch along the sides.

Best Detergents for Washing Wool

A variety of wool wash detergents are shown on a wood table

Unicorn Products

Unicorn makes really great products for cleaning wool, including Fiber Wash (this will be your main wool wash), Beyond Soft (fabric conditioner), and Beyond Clean (for really stubborn stains). I use Fiber Wash (also called Beyond Fiber Wash) on most wash cycles, and occasionally Beyond Soft (also called “Fiber/Fibre Rinse”) if something doesn’t feel as soft as I’d like it.

How to wash wool

If an item had been mildly felted, Beyond Soft can often bring it back to life and restore some softness and stretch to it!

Soak Wash

Soak wash is a really nice wash, and we use it on all our merino wool baselayers, interlock, and cashmere. I prefer the wash cashmere with soak over unicorn, and we own lots of cashmere sweaters and hats that we wash the same way we wash our wool (cashmere is an awesome outdoor fiber!).

Soak comes in some really yummy scents, Pineapple Grove and Yuzu are my favorites. They are only scented during the wash, I don’t find the woolies have any scent after the wash. Soak doesn’t need to be rinsed out, but I do usually rinse it anyways.

Eucalan

Eucalan is a great detergent for items that are not heavily soiled. It contains lanolin in the wash, so it is harder to get an item really clean with it, but it is great for a quick wash of a merino tee for a child with sensitive skin, as the lanolin in it can act as a moisturizer (unless the child is allergic to lanolin).

Other Helpful Washing Products

Fels Naphtha

Stock image of a fels naptha laundry bar

Fels naphtha works really well for things that just will not come out! You can grate it up and put it in the water, or spot treat with it.

Do always test a small part of the garment to make sure that the bar doesn’t fade the color, I’ve had my fels naphtha bar for many years but some of the newer bars have caused some fading or color issues.

Wool Wash Bar

A solid wool wash bar won’t be the only washing product you’ll want, but it’s a really useful one for spot treating. Bee Green Naturals makes this one that I’ve used for years but it is very hard to find lately.

Lanolin

Lanolin is not a detergent, but is included in this section because you can add it after the washing routine. Lanolin should only be used on clean wool (after your wash routine is complete). Wool naturally contains lanolin and it’s a natural waterproofing treatment to add some back in.

Lanolin is typically used in prepping covers for cloth diapering, but it can be nice to soften up thicker wool garments and to help soothe dry skin in the winter. Many of the kids’ heavier wool pants get lanolin baths a few times a winter.

There are many resources for washing with detailed instructions on how to make a lanolin bath (sloomb has an excellent one here), but this is a totally optional part of wool care and you do not need to use lanolin at all.

If you do decide to use it, buying a large container is much more economical than the small tubes, it will last you a really long time and you don’t need ultra high quality lanolin for treating your woolies! (Side note about lanolin, it makes wonderful lip balm! Thanks sheep!)

Washing Wool by Hand Step by Step

The quickest way to hand wash wool is in your bathroom sink. If I have a bunch of wool to wash I’ll sometimes use a tub, but doing it in smaller batches in the sink is a nice relaxing process and doesn’t take too long.

You can wash items inside out, often care labels say to do it this way. Unless I’m lanolizing, I wash them with the dirty side out, because most of our wool needs washing from play and the dirt is on the outside! During the wash and rinse cycles I will pull the pants or shirts through the water in a scooping motion to get soapy water inside, and to rinse the inside.

Doing this during children’s bathtime is a pleasant way to be present while they play in the bath, and get the washing done!

For this hand wash tutorial we’re using a pair of Wildhaven woolies (made in Alaska!). Total wash routine maybe took 30 minutes, but probably only around 5 minutes of actual washing.

Water Temperature

I don’t usually measure the temperature of my wool but the main thing is to have it be warm water to get your items clean, but not scalding hot.

The most important consideration is temperature change, as a change in temperature (going from a warm soak to a cold rinse) is one of the ways to felt your wool. Keep your temperatures reasonably consistent and you’ll be fine!

A sink full of clothes with the water running and a thermometer reading 101.7 degrees Fahrenheit. How to wash wool.

Add Detergent and Gently Agitate

Add your choice of detergents and agitate gently with your hands. The second way to felt wool is agitation! Just add in your wool, your water, and your detergent (pour this under the water as it’s filling the sink).

With most wool detergents you really don’t need very much, I typically use less than what the bottle tells me to use. If your pieces are really dirty, sometimes you’ll want to do a rinse before you even add detergent, or do several wash cycles before you get to your soak.

Soak

Once your wool and detergents are in and you’ve gently agitated your pieces, let them soak for a bit. Many detergents will have guidance on this. Once the water gets pretty murky it’s usually time for a rinse.

A colorful garment soaks in a sudsy sink

Spot Treat if Necessary

If you have some areas that haven’t come off with your regular wash (paint for example), you can grab your wool wash bar or fels naptha. If you don’t have either of those, add a little extra detergent and work it in with your fingernail very gently. A pinch motion works well, especially on things like paint.

Occasionally you’ll want to let this spot treatment soak in a bit, so leave it above the water for a few minutes before submerging and rinsing.

Rinse

You’ll be rinsing the wool several times. Drain the water and then aim to get approximately the same temp as your soak bath coming out of the tap, and rinse your items under running water.

If they still seem dirty, repeat another wash cycle. If they’re “good enough”, then rinse in the running water and then fill up a rinse bath and let them soak in clean water. Let them soak for a bit, and then pull them through the water, rinsing the inside and outside.

Some detergents (like Soak) say a rinse is not required; I usually do one anyways because I’m often getting a bit more dirt off in my rinse cycle (totally up to you how clean you want your woolies to be!).

Roll in Towels

Once you’re happy with how clean your woolies are, drain the water from the sink and gently press the wool to drain the water. I do typically squeeze the wool out, just don’t wring it out really hard and it will be fine.

The wool will still be damp, so put it on a towel.

A wool baselayer set (red pink green and purple) are shown laid out on a towel on a tile floor

Roll up the towel…

Some wool layers pink and red and purple colors) are shown half rolled up in a towel on a tile floor

And now for the most fun, let the kids step on it to press out the water. This whole process is generally one my kids love helping with, so let yours lend a hand if they’re interested!

A child's feet are shown on a towel

Lay Flat to Dry

After you’ve gotten the majority of the water out of your wool, lay it flat to dry on a drying rack.

A red pink and green wool top lays flat on a drying rack

How to Wash Wool

The wool wash routine may look long, but there’s really nothing to it. Keep a consistent temperature if hand washing, and don’t wring (twist) when drying. Don’t be afraid of wool, and stay cozy!

Related Articles:

How to Wash your Wool Layers

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