what is a sauna hat, and do you actually need one?

if you’ve spent time in a finnish or russian sauna you’ve seen them. odd pointed wool hats on the heads of people wearing almost nothing else. they look like a joke. they’re not.

what it actually does

heat rises, so the air at head height in a hot sauna is the hottest in the room, sometimes a good deal hotter than where you’re sitting. and your head is the worst-equipped part of you for it. the scalp has a dense web of blood vessels close to the surface and almost no fat to insulate it. so the head heats up fast, and that’s usually what tips you into feeling dizzy or done before the rest of you has had enough. most people leave the sauna early because their head got uncomfortable, not because their body did.

a wool hat slows that down. the fibres are crimped and covered in tiny scales, which trap pockets of still air, and still air is about the best insulator going. the hat keeps your scalp at a saner temperature while your body gets on with the actual work of the heat. you sit longer, more comfortably, and you get more out of it.

why wool, and only wool

wool is the traditional sauna material for reasons that have nothing to do with nostalgia.

it doesn’t melt. wool is mostly keratin, the same protein as your hair, and it doesn’t catch until somewhere around 570 to 600°c. a sauna runs at maybe 80 to 100. you couldn’t be further from trouble. a plastic hat is a different story, because polyester and nylon soften and can melt at far lower temperatures, and a melting synthetic on your head is exactly as bad as it sounds.

it handles sweat. wool is hygroscopic, so it pulls moisture into the core of the fibre rather than leaving it sitting on the surface, and it can hold close to a third of its own weight before it even feels wet. so the hat soaks up sweat and steam without turning into a soggy cap, dries fast afterwards, and resists the sour smell that synthetics pick up in the heat.

ours is 8mm wool felt, ultra-dense and properly thick, with a cotton rope tie and a wooden toggle so you can cinch it down and not lose it when someone gets enthusiastic with the water. no plastic on it anywhere, including the bits you don’t think about.

how to choose one

if you’re buying a sauna hat, the label is everything. look for 100% wool, ideally a thick, dense felt, because the denser it is the better it insulates. give synthetic “felt” a wide berth, whatever the price. and if it’s dyed, natural colour is the safer bet in the heat.

how to look after it

air it out after every session and it’s ready for the next one. wash it only when it actually needs it, by hand, in cool water, and never wring it or put it near a machine. press the water out, reshape it, lay it flat to dry, out of the sun. looked after, a wool felt hat lasts years. ours are built to.