Why does an eco wash cycle leave cloth nappies smelling?

Why does an eco or quick cycle leave nappies smelling?

Modern UK machines are built to save water. An eco, quick or 30-minute programme often cuts the drum fill and shortens the rinse. Cloth nappies are heavily soiled laundry: wee, poo and cream. If they do not move in enough water, detergent and ammonia stay in the fibres. That is the hamster-cage smell parents notice on a dry nappy, or the sharp wee smell when the nappy is next wet.

The UK Nappy Network's short wash guide says: cotton cycle at 40°C or 60°C, at least 2 hours 30 minutes, extra water where you have it, not the eco cycle, and a full dose of preferably non-bio powder adjusted for load size and water hardness.

Which wash cycle should I pick instead?

Which? tells parents to pre-rinse, then set a long hot wash, preferably 60°C, so nappies are fully cleaned. The Nappy Alliance says use the full cycle: quick-wash modes tend to use less water and may not clean as effectively. Oxfordshire County Council's reusable-nappy page starts with a cold rinse and then a 40°C or 60°C main wash. Follow the care label on your own brand if it is stricter.

1. 1
   Dry-pail, do not soak Store used nappies in a lidded bucket with a mesh liner or in a large wet bag. The Nappy Alliance and UK Nappy Network both say soaking can damage elastics and PUL. Wash every two to three days.
2. 2
   Cool rinse as its own cycle Run a separate 20–30°C rinse or short cool wash with no detergent (or only a small amount if your librarian has set a two-stage routine). UKNN wants this as a separate wash, not the machine's bolted-on pre-wash, so you are not washing in leftover 'poop soup'.
3. 3
   Long cotton main wash Choose cotton, intensive or allergy — whichever uses the most water and runs at least two and a half hours. Set 40°C or 60°C. Add a full dose of non-bio powder for the load size and your water hardness. Turn on extra rinse or extra water if the dial has it.
4. 4
   Check the last rinse UKNN's rule of thumb: at least 3 cm of suds in the main wash, and no bubbles left in the final rinse. Rinse again if bubbles remain, then adjust the dose next time.
5. 5
   Line-dry if you can Which?, UKNN and Real Nappies for London all point to air-drying. Sunlight helps stains. Keep bamboo off a radiator that is too hot to touch. Tumble only if the care label allows, on a cool setting.

How much detergent and water do smelly nappies need?

Smells come from too little detergent, too much detergent, or a drum that is too empty to agitate. UKNN lists those three causes on its FAQs. Hard-water areas (much of London and the South East) usually need more powder than soft-water areas. Real Nappies for London says the same for London taps.

• Dose for a dirty load, not a shirt load. Start with the pack's full dose for the drum size, then tweak using the suds rule above.
• Prefer powder. The Nappy Alliance says powder is less likely to leave a residue than liquid. Skip fabric conditioner, 2-in-1s and soap-nut or oil-rich 'eco' liquids that coat fibres.
• Do not pack the drum solid. Nappies need room to move. If the load is small, UKNN says pad it with towels, muslins or kitchen cloths rather than running a half-empty eco wash.
• A jug of water in the drum is a last resort. UKNN allows pouring a jug on top of the nappies before the cycle starts. Do not pour extra water through the drawer mid-cycle — that can unbalance the machine.

NHS nappy-rash advice is about changing wet or dirty nappies promptly and keeping the skin clean and dry. A smelly stash can sit damp against skin. If a rash does not settle, use the NHS page and speak to a GP or health visitor — MayTally does not give medical advice.

Do eco-eggs and soap nuts clean cloth nappies?

They are a short aside, not a second wash method. Older nappy-network pages sometimes listed eco-eggs or soap nuts as a light option. Current UK Nappy Network and Nappy Alliance guidance is a full dose of ordinary non-bio powder. Nappies are the dirtiest load in most houses. An egg or a few nuts does not lift ammonia or cream the way a detergent dose does, and that under-wash is a common route to smells.

If you want a lower-impact routine, change the drying (line-dry, no tumble) and the programme (cotton, not eco), not the cleaner. Do not add vinegar, bicarb, Calgon, bleach or oxygen stain removers as a regular habit — UKNN says those can damage PUL and elastic over time.

How do I strip-wash a stash that still smells?

If nappies still smell after a correct cotton routine, both UKNN and the Nappy Alliance describe a one-off strip wash. The cause may be too little detergent or a detergent crust — the reset is the same.

1. 1
   Start in a clean machine Run a maintenance wash on the empty machine if it has not had one recently. Real Nappies for London flags monthly maintenance washes when you wash nappies often.
2. 2
   Wet the nappies The Nappy Alliance starts with a rinse or cool quick wash, no spin, no detergent.
3. 3
   Full 60°C wash with a full dose Use a full-length 60°C cotton wash and a full dose of non-bio powder. Add extra rinse if the machine has it.
4. 4
   Wash again with no detergent Run 40°C or 60°C with no powder. Repeat rinses until you cannot see bubbles.
5. 5
   If smells persist UKNN's next step is an icy-cold soak for 24 hours, then repeat the strip. After that, fix the everyday routine so residue does not return. A change of detergent brand is the last tweak, not the first.

You do not need to strip nappies that have just come from a library. The Nappy Alliance says libraries already follow a strict wash between hirers.

When should I wash at 60°C rather than 40°C?

UKNN says wash at 60°C if the baby is under 3 months, has repeated or unusual nappy rash, is unwell, or you have more than one baby sharing the stash. Real Nappies for London uses 60°C for babies under 6 months while they are still building resistance to infection. The Nappy Alliance says heavily soiled nappies belong on a 60°C full cycle, and that PUL should not go to 90°C. UKNN adds that going hotter than 60°C is not needed and can shorten the life of the nappies.

In shortIn short: the eco button is the wrong tool for cloth. Use a long cotton wash with enough water and a full powder dose. Strip once if the stash already smells, then keep the cotton routine. Check your brand's care label, and use the NHS nappy-rash page if skin is sore.