Short answer: It depends on the material. 40°C is the optimal temperature for cotton socks — bacteria and odors are removed without damaging the fibers. Bamboo viscose belongs in the machine at 30°C and not in the dryer. 60°C makes sense for cotton only, and even there only for athlete's foot, illness or extreme soiling. 30°C is also sufficient for lightly worn socks and merino wool.
The washing temperature affects three things simultaneously: hygiene (are bacteria killed?), material care (are the fibers damaged?) and energy consumption (what does the wash cost?). The sweet spot depends on the material: for cotton it is 40°C, for bamboo viscose 30°C — there the lower temperature balances the three factors best, because the viscose fibre is more heat-sensitive.
Modern detergents are optimized for 40°C: enzymes and surfactants work effectively against bacteria, sweat and odor at this temperature. Cotton tolerates 40°C without damage. Bamboo viscose does not: the viscose fibre swells more in heat and loses softness and dimensional stability — it is washed at 30°C and air dried. Elastane (the waistband component that provides elasticity) retains its properties at 40°C for 50+ washes. Colors stay more vibrant than at 60°C. Energy consumption: 40°C uses about 45% less electricity than 60°C.
Matching the article
All Socks
34 styles · from €19,90
View collection →
For athlete's foot (Tinea pedis): fungal spores survive 40°C — for cotton socks only a 60°C wash cycle kills them reliably. In case of acute infection, wash all cotton socks at 60°C and as a separate load. Bamboo viscose cannot take that heat: here you add a hygiene rinse to the softener compartment and wash at 30°C — the product works against germs at low temperatures too and is gentle on the viscose fibre. For gastrointestinal infections: noroviruses and certain bacteria survive 40°C. For colds and flu: cotton socks as a precaution at 60°C, bamboo viscose at 30°C with a hygiene rinse. For heavily soiled cotton athletic socks: if the odor doesn't come out at 40°C, a one-time 60°C wash cycle helps.
Elastane fibers are more stressed at 60°C — the waistband stretches out faster. Bamboo viscose therefore has no place in this temperature range at all: it already loses softness above 30°C, and permanently at 60°C. Colors fade faster — black socks turn gray. Lifespan is reduced by an estimated 20-30% with regular 60°C instead of 40°C.
For bamboo viscose, 30°C is the standard temperature, not the exception — the fibre stays soft and dimensionally stable, and the dryer remains off limits. For lightly worn cotton socks (home office, short walk) 30°C is also enough. For merino wool: wool wash program at 30°C is mandatory — hotter and the wool will felt. Disadvantage: at 30°C not all bacteria are killed — for athletic socks, sweaty feet or infections a hygiene rinse therefore belongs in the wash, working against germs at low temperatures too while being gentle on the fibre.
| Material | Standard | Maximum | Emergency (fungus/illness) |
|---|---|---|---|
| Bamboo viscose | 30°C | 30°C | 30°C with hygiene rinse (no 60°C) |
| Cotton | 40°C | 60°C | 60°C |
| Merino wool | 30°C | 30°C | 30°C (never hotter!) |
No fabric softener — destroys elastane and blocks moisture absorption, regardless of temperature. Wash inside out — the sweaty inside is cleaned directly. Full program instead of quick wash — sweat needs the full wash time. Gentle spin (800-1,000 RPM) instead of 1,400 RPM — protects the fibers.
Yes — modern detergents contain enzymes that actively break down proteins (sweat, skin cells) at 40°C. The hygiene at 40°C with modern detergent is comparable to 60°C 20 years ago.
Cotton socks together at 40°C: yes. Bamboo viscose you wash separately at 30°C — washing them together would only work at the temperature that suits both, and that is 30°C. Merino wool separately at 30°C in wool program. For the first 3-5 washes, separate dark and light socks (color may bleed).
Cotton: 40°C, no fabric softener, inside out, gentle drying. Bamboo viscose: 30°C, no fabric softener, inside out, air dry — never in the dryer. Merino wool: 30°C wool program, wool detergent, never tumble dry. Athlete's foot/illness: cotton once at 60°C, bamboo viscose at 30°C with a hygiene rinse, in both cases as a separate wash. Persistent odor: vinegar in fabric softener compartment, full program instead of quick program. Cotton athletic socks: 40°C full program (no quick program). These rules cover all common sock materials and require no additional effort — just habit. The reward: double lifespan, better hygiene, fewer sock purchases per year.
A wash at 60°C consumes about 1.2-1.5 kWh of electricity. At 40°C only 0.7-0.9 kWh — 40-45% less. At 30°C: 0.4-0.5 kWh. Anyone who washes 3 times per week and switches from 60°C to 40°C saves 50-70 kWh over a year — that corresponds to €15-25 in electricity costs and ~25-35 kg CO2. The socks last longer (less elastane wear) and the environment benefits. Win-win.
For normal cotton athletic socks after training: 40°C with full wash program (no quick program!) is sufficient. Athletic socks made of bamboo viscose run at 30°C with the full program. Sweat needs the full wash time to be dissolved from the fibers. For cotton athletic socks with athlete's foot: 60°C necessary to kill spores — even if it stresses the sock more. With bamboo viscose, the hygiene rinse takes over that job at 30°C. For yoga socks and light fitness: 40°C for cotton, 30°C for bamboo viscose. For cotton marathon socks after competition: 40°C with pre-wash function — removes sweat and vaseline residues more thoroughly.
Instead of switching to 60°C across the board: first check if fabric softener is being used (blocks cleaning). Second, replace quick program with full program. Third, add a splash of vinegar to the fabric softener compartment (kills bacteria, neutralizes odor). Only if these three measures don't help: wash cotton socks once at 60°C — but not permanently, because it shortens lifespan. With bamboo viscose, use a hygiene rinse at 30°C instead. Persistent odor despite everything: the sock has reached its lifespan and should be replaced.
SOKKS recommends: cotton socks at 40°C, bamboo socks at 30°C and not in the dryer — both without fabric softener and washed inside out. With proper care, SOKKS socks last well beyond the guaranteed 12 months. Oeko-Tex Standard 100 certified. 4 pairs for €19.90 with 12-month anti-hole guarantee. Thousands of verified customer reviews on Judge.me confirm the quality.
40°C covers almost all washing situations for cotton socks — hygienic, material-friendly and energy-saving. Bamboo viscose and merino wool run at 30°C. 60°C remains reserved for medical necessity with cotton (fungus, illness); with bamboo viscose the hygiene rinse takes over that job at a low temperature. These three temperatures are all you need to know — the rest is care mythology that does more harm than good.
Exclusively for you
Your upgrade starts with your feet.
Sign up and get 10% off your first order.
By signing up you agree to our Privacy Policy.
Your upgrade starts with your feet.
10% off your first order.
By signing up you agree to our Privacy Policy.
