Sauna wood: why sweat must not get onto the wood and how your sauna towel protects the bench
"Towel underneath!" is the best-known sauna rule. Many people think it's only about hygiene – but it's at least as much about the sauna wood. Sauna benches are made of untreated wood, and it absorbs everything that lands on it. In this guide you will learn which woods are common in saunas, why sweat doesn't belong on the wood, how your sauna towel protects the bench and how to care for sauna wood at home.
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We have been running the Meri Sauna at Lake Kulkwitz for more than 18 years. As sauna operators, we see the benches every day from the perspective of those who keep them clean.
What is sauna wood? The usual types of wood
Sauna wood refers to woods that cope well with the heat of a sauna: they should release little resin, hardly splinter, not warp much and not feel too hot on the skin. Benches and lounging surfaces have stricter requirements than wall cladding, because you sit directly on them. These types of wood are common in saunas:
| Wood | Typical use | Properties (as commonly described) |
|---|---|---|
| Abachi | benches, backrests | light, resin-free, feels comparatively cool |
| Aspen / thermo-aspen | benches, interior fittings | light-coloured, resin-free, low splintering; thermo-aspen is heat-treated and darker |
| Hemlock | walls and benches | low in resin, even grain |
| Nordic spruce | mainly wall cladding | inexpensive, typical sauna look with knots, can release resin |
| Red cedar, Swiss stone pine | walls, accents | distinctive natural scent, more for walls than for lounging surfaces |
Which wood is used in your favourite sauna doesn't matter for the towel question: all these woods remain untreated on the lounging surface – and that is exactly what makes the towel so important.
Why sauna wood stays untreated
Varnish, glaze or ordinary furniture oil have no place on sauna benches. At the high temperatures in the cabin they would smell, become sticky or feel unpleasantly hot. That's why sauna wood on benches and loungers is usually left natural. The advantage: the wood can breathe, absorbs moisture and releases it again when ventilated. The disadvantage: it absorbs everything else too.
What sweat does to sauna wood
In the sauna you sweat a lot – that's the whole point. Sweat isn't just water; it also contains salts and fats. Together with skin flakes and residues of shower gel or body oil, it soaks straight into the open wood if there's no towel. The consequences:
- Dark stains and marks: especially where your bottom, back and feet rest. They can only be removed by sanding.
- Odour: sauna wood that repeatedly absorbs sweat stops smelling fresh over time.
- Hygiene: on a bench where many people sweat, you don't want to lie in other people's sweat – and vice versa.
- More work and a shorter lifespan: heavily used benches have to be sanded more often or replaced sooner.
That's why practically every sauna has the rule: no part of the body touches the wood – not even the feet.
How your sauna towel protects the sauna wood
- Choose one that's big enough: the towel should be at least as long as you are. With 180 × 100 cm or 175 × 90 cm, most adults lie completely on fabric.
- Spread it out fully: use the whole surface instead of folding the towel narrow.
- Cover everything when sitting: even when sitting, the towel goes under your bottom, thighs and feet. If you lean back, it should also be behind your back.
- Don't forget your feet: the soles of your feet sweat too – without a towel, that's exactly where most stains appear.
- Take it with you: the wet towel doesn't stay on the bench when you leave the cabin.
Which towel protects best?
What matters is that the towel absorbs moisture before it soaks through. Cotton is very well suited to this. A dense sauna towel like the DOTWAVE Sauna Towel XL (175 × 90 cm, approx. 900–950 g) absorbs a lot of moisture before anything gets through. A flat-woven hammam towel Ocean (approx. 180 × 100 cm, approx. 400 g) is lighter and also does the job well for most people. If you sweat heavily or do long rounds, the denser towel is the safer choice.
Caring for sauna wood: what helps in a home sauna
In a public sauna, the operator takes care of the benches. In your own sauna, it's up to you. These general care rules for sauna wood have proven themselves – but your sauna manufacturer's instructions always take precedence:
- Ventilate after every session: leave the door and vents open so the wood can dry through. Damp wood in a closed cabin is the most common cause of mildew stains.
- Don't dry towels in the cabin: wet textiles keep the moisture in the room.
- Wipe regularly: wipe benches with a damp cloth and lukewarm water, if necessary with a mild cleaner suitable for saunas.
- No harsh products: aggressive cleaners, chlorine or furniture polish can attack the wood and smell in the heat.
- Sand off stains: stubborn dark patches can be removed with fine sandpaper in the direction of the grain. Then remove the dust thoroughly.
- Take out loose bench boards: if the lounging surfaces are removable, take them out now and then and let them dry outside the cabin.
The best care product, however, is still the sauna towel: the less sweat gets into the sauna wood, the less often you have to sand.
Typical mistakes that damage the wood
- Infusion oil directly on the bench: essential oils and infusion concentrates belong diluted on the stones, never undiluted on the wood.
- Going in with lotion on: rinse off body lotion, body oil or scrub residue before the sauna session – otherwise it ends up in the towel and, in the worst case, in the wood.
- A towel that's too small: a 140 cm shower towel leaves feet or head on the wood. That's the most common reason for stains at the end of the bench.
- Drinks in the cabin: spilled juice or tea leaves sticky, dark patches. Drinking belongs in the break.
Sauna wood and consideration: one towel for everyone
In a public sauna you share the bench with many others. Every towel that's properly placed helps keep the wood light and clean, so the next guest feels comfortable too. If you're wondering what else is part of towel etiquette, take a look at our sauna etiquette guide.
Related reading: Sauna etiquette: the most important rules for your sauna visit · Top or bottom? Which sauna bench is right for you · Sauna towels for your home sauna: towel rules, protecting the wood and how many you need
Conclusion
Sauna wood on benches stays untreated – and therefore absorbs sweat, fat and care residues directly. The result is stains, odour and more cleaning work. A sufficiently large cotton sauna towel, spread out fully and under your feet too, reliably prevents this. At home, regular ventilation and gentle wiping complete the picture.
Frequently asked questions
Why shouldn't sweat get onto the sauna wood?
Because sauna benches are untreated and sweat, along with salts and fats, soaks straight into the wood. This leads to dark stains and odour, and it's unhygienic for other guests.
Which wood is common for sauna benches?
Abachi, aspen and hemlock are common because they are low in resin and don't feel too hot. Nordic spruce is often used for wall cladding.
Do my feet have to be on the towel too?
Yes. The soles of your feet sweat too, and that's exactly where most stains appear on the wood without a towel.
How do I clean sauna wood in a home sauna?
Ventilate well after every session, wipe the benches regularly with lukewarm water and remove stubborn stains with fine sandpaper. Avoid varnish, furniture care products and harsh cleaners, and follow the manufacturer's instructions.
Can you oil sauna wood?
Lounging surfaces are usually left untreated. There are special sauna care products – whether and where they are suitable for your sauna is stated in the manufacturer's instructions.
Personally written by Martin – founder of BeachAndSteam and sauna operator at Lake Kulkwitz for more than 18 years.