How to wash and care for a sauna hat
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You sweat into your sauna hat every single session. Wool handles that better than any other fabric, but it does need a bit of looking after. Most sauna hats that get ruined aren't worn out. They're ruined in one go, by a hot wash, a washing machine or a tumble dryer.
This guide covers what to do after every session, how to properly wash a wool or merino sauna hat, and how to fix the usual problems: smell, shrinking, stretching and pilling.
The short answer: hang your sauna hat up to air dry after every session. Hand wash it in cool water (30°C max) with a wool detergent only when it starts to smell, roughly every 10 to 15 sessions. Press the water out instead of wringing, reshape it, and dry it flat away from direct heat. Never tumble dry a wool sauna hat or wash it hot. Heat combined with water and friction shrinks wool, and it won't come back.
Sauna hat care at a glance
|
|
Do |
Don't |
|---|---|---|
|
After each session |
Hang it up somewhere with airflow |
Ball it up in your gym bag |
|
Washing |
Hand wash, cool water (30°C max), wool detergent |
Hot water, bio detergent, fabric softener, bleach |
|
Wringing out |
Press it gently, then roll it in a dry towel |
Twist or wring it |
|
Drying |
Flat, or over a bowl to hold the shape |
Tumble dryer, radiator, hot press, direct sun |
|
How often to wash |
Every 10–15 sessions, or when it smells |
After every session |
|
Storage |
Clean, fully dry, in a breathable bag |
Sealed plastic, or put away damp |
What to do after every sauna session
This is 90% of sauna hat care, and it takes about 30 seconds.
- Take it off and shake it out. Get rid of loose hair and any bits from the bench.
- Rinse it if it's soaked. After a long or very sweaty session, a quick rinse under the cold tap gets the salt out. Squeeze it gently, don't wring it.
- Hang it somewhere with airflow. A hook, the back of a chair, a coat stand. A merino sauna hat dries in a few hours. A thick felt hat can take a day.
- Let it dry fully before the next session. If you go every day, it's worth having two hats and rotating them.
The one habit that ruins sauna hats faster than anything else is leaving them damp in a gym bag. Wool resists odour well, but no fabric survives being balled up wet for two days. That's where the smell comes from, not the sauna itself.
On the walk home, it's fine to just keep wearing it. A merino sauna beanie will dry out on your head on the way.
How often should you wash a sauna hat?
Less often than you'd think. If you air it out after every session, a wool sauna hat only needs a proper wash every 10 to 15 sessions. Wash it sooner if any of these happen:
- It still smells after it's fully dry
- It feels stiff or crunchy from dried sweat salt
- There's visible staining, usually around the band
- You use oils or styling products in your hair before the sauna
Washing wool too often does more harm than good. Every wash is a small risk of shrinking, and it strips some of the natural lanolin that helps wool resist water and smell.
How to hand wash a sauna hat, step by step
You'll need a sink or basin, a wool detergent (any wool wash, or a gentle non-bio detergent), and a dry towel. It takes about 20 minutes plus drying time.
- Fill a basin with cool water. 30°C max, so lukewarm at most. Cold is fine.
- Add a small amount of wool wash. A teaspoon or so. Don't use regular bio detergent. The enzymes in it are made to break down protein stains, and wool is protein.
- Turn the hat inside out. The sweat and skin oils sit on the inside, so that's the side you want to clean.
- Submerge and squeeze gently. Press it through the water two or three times, then leave it to soak for 10 minutes. Don't rub or scrub. Friction is what felts wool.
- Rinse in water the same temperature. Drain the basin and refill it with clean water at the same temperature. Sudden hot-to-cold changes shock the fibres and encourage shrinking. Repeat until no suds come out.
- Press the water out. Squeeze it gently in your hands. Then lay it flat on a dry towel, roll the towel up, and press down on the roll.
- Reshape and dry. Turn it right side out, ease it back into shape, and dry it flat or pulled over a bowl. Keep it away from radiators, the hot press and direct sunlight. Allow 12 to 24 hours.
That's it. Cool water, no friction and no heat while drying are the three things that keep a wool hat its original size.
Can you machine wash a sauna hat?
We recommend hand washing, and so does almost every wool sauna hat maker. The washing machine is the most common way sauna hats get shrunk.
If you're going to use the machine anyway, keep the risk down:
- Use the wool or hand-wash cycle, never a normal cycle
- Cold, or 30°C max
- Lowest spin setting
- Put the hat in a mesh laundry bag
- Wool detergent only, no fabric softener
- Wash it on its own or with other wool, not with towels or jeans
Cotton and linen sauna hats are different. They can usually go in the machine on a cool, gentle wash. Air dry them either way.
Can you tumble dry a sauna hat?
No. A tumble dryer is heat plus constant tumbling, which is exactly what turns a wool hat into a toddler's hat. This goes for cotton and linen sauna hats too. Natural fibres shrink in the dryer, and they lose their shape.
How to dry a sauna hat without shrinking it
Press the water out, roll it in a towel, then dry it flat or over a bowl at room temperature. A bowl roughly the size of your head is ideal for keeping the crown shape. Skip the radiator, the hot press, the stove and direct sun. They speed things up but leave wool stiff and can shrink it.
Will the sauna itself shrink my wool hat?
No, and this is one of the most common questions. Wool shrinks when it's wet, hot and being rubbed or agitated all at once. In the sauna, your hat gets hot and a bit damp from sweat, but it isn't being agitated. That's why the same hat that's fine at 90°C on the top bench can be ruined by a 40°C machine wash.
Two things to avoid: wringing the hat out while it's still hot, and soaking it before you go in. Some people lightly dampen a thick felt hat first, but a soaking wet hat holds heat against your scalp and can feel scalding when someone throws water on the stones. With a merino beanie, just wear it dry.
Fixing common sauna hat problems
My sauna hat smells
Wash it using the steps above. For a smell that won't shift, add a splash of white vinegar to the rinse water, about a tablespoon per litre, then rinse once more in clean water. Let it dry completely. If it keeps coming back, the cause is almost always being put away damp, so change where it lives between sessions.
My sauna hat has shrunk
Mild shrinking can often be partly reversed. Soak the hat for 20 to 30 minutes in lukewarm water with a good squeeze of hair conditioner, which relaxes the fibres. Gently stretch it back out while it's damp, then dry it over a bowl or ball that's the right size. Don't rinse the conditioner out fully. Be honest with yourself here: if the hat has properly felted, gone thick and stiff with no stitch definition, it isn't coming back.
My sauna hat has stretched out
Wash it as normal and dry it flat. Wool has a natural memory and usually pulls back in a bit after a wash. Don't try to shrink it on purpose with hot water. You can't control how much it goes.
My sauna hat is pilling
Small bobbles are normal with merino, especially in the first few weeks. They come from friction against the bench and your hair. Take them off with a fabric shaver or a wool comb, gently. Don't pull them off by hand, which drags out more fibre.
Sweat stains or yellowing around the band
Give it a longer soak, 30 minutes, in cool water with wool wash. For a stubborn mark, dab it with a mix of two parts water to one part white vinegar before washing. Never use bleach on wool. Chlorine bleach damages wool fibres and can leave holes.
How to store a sauna hat
Between sessions, a hook with airflow is all it needs. For longer breaks, like a summer off the sauna:
- Wash it first. Clothes moths go for wool with sweat and skin oils in it.
- Make sure it's completely dry.
- Store it in a breathable cotton bag or a drawer, not sealed plastic.
- A cedar block or a lavender sachet nearby helps keep moths away.
Care by sauna hat material
Not every sauna hat is wool, and the rules change with the fabric. If you're not sure which you've got, check our guide to sauna hat styles.
|
Material |
Washing |
Drying |
Drying time after a session |
|---|---|---|---|
|
Merino wool knit (beanie) |
Hand wash, cool |
Flat or over a bowl |
A few hours |
|
Felt wool (bell or bucket) |
Spot clean or hand wash, lukewarm; brush when dry |
Over a bowl to hold the shape |
Up to a day |
|
Cotton or terry towel |
Machine wash, cool, gentle |
Air dry |
Several hours |
|
Linen |
Machine wash, cool, gentle |
Air dry |
A few hours |
|
Acrylic or polyester |
Don't wear these in a sauna |
— |
— |
Caring for The 90 Lifestyle Merino Wool Sauna Hat
The Merino Wool Sauna Hat from The 90 Lifestyle is a fitted merino wool beanie made for traditional saunas. It's one size (58–60cm, with a good bit of stretch), unisex, and comes in Grey, Cream and Black.
Care for it the same way as any merino sauna hat:
- Hang it up to air dry after every session
- Hand wash in cold water when it needs it, which isn't often, because merino is naturally odour-resistant
- Dry it flat, never in the tumble dryer
We made it merino rather than felt partly for this reason. It dries in hours instead of a day, holds its shape after repeated use, and doesn't need fussing over.
If you're buying for yourself or as a gift, the Sauna Hat & Towel Bundle pairs the hat with our 100% cotton waffle sauna towel for €54.99, which also gets you over the €50 free shipping line. The towel is the easy one: machine wash it, and skip the fabric softener so it stays absorbent. For the full set with the cork-sleeved sauna water bottle, there's the Sauna Accessories Bundle.
Sauna hat care FAQs
How often should you wash a sauna hat?
A wool sauna hat that's aired out after each session only needs washing every 10 to 15 sessions, or whenever it smells after drying. Washing wool more often than that adds shrinking risk and strips the natural lanolin that helps it resist odour.
Can you put a sauna hat in the washing machine?
Hand washing is safest for wool and merino sauna hats. If you use a machine, choose the wool cycle, cold water, the lowest spin and a mesh laundry bag. Cotton and linen sauna hats can usually go in the machine on a cool, gentle wash.
Can you tumble dry a sauna hat?
No. Tumble drying shrinks wool sauna hats and can shrink cotton and linen ones too. Always air dry, either flat or pulled over a bowl to hold the shape.
What detergent should I use on a wool sauna hat?
Use a wool wash or a gentle non-bio detergent. Avoid bio detergents, because their enzymes break down protein and wool is a protein fibre. Avoid fabric softener and bleach too.
Why does my sauna hat smell?
A smelly sauna hat has almost always been left damp, usually in a gym bag. Wash it in cool water with wool detergent, add a splash of white vinegar to the rinse if the smell is stubborn, and hang it somewhere with airflow after every session from now on.
Does the heat of the sauna shrink a wool hat?
No. Wool shrinks when heat, water and friction act on it together, like in a hot wash. Sitting in a dry sauna isn't enough on its own, which is why a wool hat can handle 90°C on the bench but not a hot machine wash.
Can you fix a shrunken sauna hat?
Sometimes. Soak it for 20 to 30 minutes in lukewarm water with hair conditioner, gently stretch it back out, and dry it over a bowl the size of your head. This works for mild shrinking. A hat that has fully felted won't recover.
Should you wet a sauna hat before using it?
Not a merino one. Put it on dry. A soaking wet hat holds heat against your scalp and can feel scalding when water goes on the stones.
Related reading
- Sauna Hat Styles: Which One Actually Works?
- Does a Sauna Hat Protect Your Hair?
- Sauna hat vs sauna beanie: which is best?
- What Are the Benefits of Sauna Hats?
- Best sauna towels: waffle weave
Looking for a sauna hat that's easy to look after? The Merino Wool Sauna Hat dries in hours, holds its shape, and you can wear it home without anyone looking twice. Shop the full Modern Sauna Collection.
