Towels smell when wet? Why clean towels go sour after one use

Towels smell fine dry, then sour or musty after one use? Residue and damp in the loops, a quick towels-or-washer check and a four-step reset.

Clean towels that turn sour after one shower are often carrying what the wash left behind: soil, detergent and softener in the loops, and damp they never fully lost. Getting wet again seems to be what lets it smell.

The towels come off the line or out of the tumble dryer smelling of nothing. After one shower they smell sour, like a wet dishcloth. You’ve probably tried vinegar, baking soda, a scent booster or a bigger dose of detergent, and the bigger dose can make it worse. It isn’t that you don’t wash them often enough. It’s what the wash leaves behind. Here’s how to tell whether it’s the towels or the machine, and a reset that holds.

Why towels smell the moment they get wet

Something seems to survive the wash and the drying without smelling, then show itself once the towel is damp again.

A team including researchers at Kao, a Japanese detergent maker, studied a sour laundry smell often described, they write, as “wet-and-dirty-dustcloth-like”. People in Japan noticed it on washing dried indoors “or when using their already-dried laundry”. The team traced it to a bacterium, Moraxella osloensis. Its tolerance of drying is, they say, “one of the possible reasons” it survives “during and even after drying”. The study isn’t about towels specifically, but it fits the towel complaint.

Three things the wash can leave in the loops:

  • Soil. Body soils left on towels “will break down over time”, according to Tide, a P&G detergent brand. Terry loops are built to hold water, so they likely hold more of whatever the rinse didn’t carry away.
  • Detergent and softener residue. When towels “smell and lack absorbency—especially shortly after being laundered—it’s a sign that detergent and fabric softener have built up in the fabric”, says Speed Queen, a washer maker. It says residue stops towels drying as well and makes them more of “a breeding ground for bacteria”.
  • Damp. Bacteria grow faster on towels that never dry completely, per the same page.

Cold-only washes may add to it. A Furtwangen University study of home washing machines lists low-temperature washing among trends that “facilitate microbial survival of the laundry processes”. Put simply, more of what lives in the fabric can come through a cool wash.

Is it the towels or the washing machine?

A rough two-minute check:

  • Sniff the empty machine, door or lid open. On a front-loader, pull back the folds of the rubber door seal and check the detergent drawer. On a top-loader, try the softener dispenser and under the rim.
  • Sniff something washed and dried that isn’t a towel, such as a T-shirt or pillowcase, after splashing it with water. Straight out of the wash proves little.

Then follow whichever fits:

  • The machine smells. Clean it first, or freshly reset towels can pick the smell straight back up. On front-loaders the door seal is a known hiding place (the Furtwangen study found M. osloensis in the seals of 9 of its 13 machines).
  • The machine smells fine, but other laundry goes sour too. The cause is probably something every load shares, so run the reset on the towels and work through why clothes smell musty after washing.
  • Only the towels smell. Reset them.

How to get the smell out of towels: a four-step reset

Do all four together, starting with the next towel wash. (Stripping years of build-up? Read the note after step 4 first.)

  1. Wash hotter, within the care label. Use the warmest temperature the label allows, as Tide advises, which also moves you away from cold-only washes. Wash towels on their own, with room to move. Coloured or bamboo towels may have a lower limit, and the label wins.
  2. Use the dose line on the detergent, which is often far below a full cap. LG, for example, gives 2 tablespoons for its own machines, or 1 if concentrated, on its top-loader odour page. Suds left after rinsing mean too much, per Speed Queen, which also notes hard water may need more. If your dose crept up because the towels smelled, that’s the trap — more detergent, more residue, more smell.
  3. Skip fabric softener. It’s part of the residue, and Speed Queen says it “builds up on towels”.
  4. Run the complete-dry test. If towels still smell after washing and drying, drying is often a weak spot. Unload as soon as the cycle ends and dry fully. Before folding, feel the hems and the woven band near each end. Cool or damp means not dry, so back in the dryer or back on the line. Between uses, hang towels spread out, never in the hamper wet.

Stripping first (optional). Do this before step 1. Speed Queen’s method is a hot wash with one cup of vinegar and no detergent, then a second hot wash, without drying in between, with one cup of baking soda. Keep both within the care label, and expect it to hold only if steps 2 to 4 stop the residue going back on. Don’t add bleach to either wash: never mix bleach with vinegar, ammonia or other cleaners, or run one straight after the other.

Towels still smell musty after the reset?

Sniff the seal and drawer (or a top-loader’s dispenser) again. A faint machine smell is easy to miss.

If it’s only the towels, something between washes is probably putting residue or damp back. Because towels hold more water and soil (see above), everyday conditions like a load left wet in the drum or an overfilled one tend to show in towels first.

The musty-laundry guide covers those causes in order, starting with a load left wet and a packed drum.