Unlike most big merino sock brands, we don't superwash our merino. No chlorine treatment, no resin coating, no Total Easy Care (TEC).
What superwash is
Under a microscope, a wool fibre is covered in tiny overlapping scales. Add heat, moisture and agitation and those scales lock together, which is what makes wool shrink and felt.
Superwash is the industry's fix. It's a two-step process:
- A chlorine treatment that eats away at the scales on the outer surface of the fibre.
- A resin coating (a polyamide called Hercosett) bonded over the fibre to smooth out what's left.
The result is wool you can throw in a hot wash. TEC is a machine-washable standard that's usually met with the same chlorine-and-resin treatment.
Why we skip it
Untreated merino has a natural water-repelling outer layer, while the inside of the fibre soaks up sweat vapour from your skin. That combination helps keep skin drier, and drier skin means less friction and fewer blisters.
Superwash strips that outer layer away. A 2024 study by AgResearch in New Zealand found the chlorine treatment breaks the bonds holding that water-repelling layer to the fibre. We make socks for hikers, trail runners and ultra runners, so we'd rather keep it.
The trade-off
Untreated merino can shrink with heat and rough washing, so it needs a little care:
- Wash cold (under 30°C / 86°F) on a gentle or wool cycle, or hand wash.
- Use mild soap. No bleach or fabric softener.
- Hang or lay flat to dry. Do not tumble dry.
See our Care Instructions article for the full guide, including fluff and pilling. Damage caused by tumble drying falls outside our care guidelines and isn't covered under warranty.
If your socks have shrunk even though you've followed these steps, get in touch and we'll take a look.