Why does laundry get smelly if it stays wet? A textile scientist explains how to fix it

When laundry is left damp after a wash, it becomes an inviting environment for microbes to grow, leading to unpleasant odors. Bacteria such as Moraxella osloensis produce compounds that contribute to the "wet rag" smell, and studies have shown that these microbes can survive both washing and drying. The source also highlights that washing machines themselves can harbor these microbial biofilms, which can reinfect freshly laundered clothes.

The type of fabric plays a significant role in how much these odors persist. Cotton, being hydrophilic, soaks up water and leaves less space for sweat and sebum residues to accumulate, reducing the odor-causing potential. In contrast, hydrophobic synthetic fabrics like polyester and nylon absorb oily residues, providing a feast for bacteria to thrive. This explains why synthetic fabrics often retain smells more persistently than natural fabrics.

To combat the musty smell of wet laundry, the best solution is to wash the clothes again, ideally at a higher temperature. Soaking the laundry in a vinegar solution before the wash can also help eliminate bacteria. In addition, ensuring the laundry is dried thoroughly and promptly, preferably in a well-ventilated area, can help prevent microbial growth.

Using laundry boosters with enzymes and oxygen bleach can further enhance the cleaning process, while regularly cleaning the washing machine itself can help break the cycle of reinfection. Ultimately, understanding the interplay between fibre types, laundering practices, and garment lifespan can help maintain fresh-smelling clothing.