Use the wool or delicates cycle on your washing machine, keep water at or below 40°C, fill the drum no more than one-third full, and reach for a mild, neutral detergent. Getting those four things right before the garment leaves the machine gives flat drying the best possible start.
Why wool fibres react badly to the wrong wash conditions
Wool is a natural protein fibre whose microscopic surface scales can lock together permanently when exposed to heat, agitation or alkaline chemistry. That locking is what causes felting and shrinkage, and it cannot be reversed once it has happened. Because wool is naturally resistant to odours, stains and creasing, it needs washing less often than many fabrics, which means each wash matters more. Getting the programme, load and detergent right every time protects the garment across its whole life.
Choosing the right cycle and temperature
For machine-washable wool, Woolmark recommends the wool setting, which typically runs at gentle action and 40°C . If your machine has no wool cycle, a cold-water wash or delicates cycle is the appropriate substitute. The critical characteristic of these programmes is reduced mechanical action, not just lower temperature: the drum moves more slowly and less forcefully, which limits the friction that causes fibres to felt.
The international care-labelling system reflects this. GINETEX describes the double-bar wash-tub symbol as a very mild washing cycle suited to woollens, and specifies that the drum should be no more than one-third full for the 40°C very mild wash . The same symbol appears on Woolmark-approved garment labels. Always let the label on the specific garment take precedence: some pieces are hand-wash only, and some must not be wet-cleaned at all.
Loading the drum correctly
Overloading is one of the most common mistakes with wool. When the drum is too full, garments press against each other throughout the cycle, increasing friction and the risk of felting. The drum should be no more than one-third full for the 40°C very mild wash for machine-washable wool , a much stricter limit than the roughly two-thirds guideline that applies to easy-care synthetics. In practice this usually means washing one or two knitwear items rather than bundling several together. If you are sorting a mixed autumn load, wool should be separated out rather than tucked in with heavier cotton items; the guide to sorting a mixed autumn laundry load covers that step in more detail.
Detergent: mild and neutral only
Ordinary biological detergents contain enzymes designed to break down protein-based stains. Wool is itself a protein fibre, so those enzymes can attack the fabric directly. Woolmark recommends a neutral, mild detergent, and suggests looking for the Woolmark symbol on the packet as a guide to suitability . Avoid powder detergents if they do not dissolve fully in cool water, as undissolved granules can abrade fibres. Use the quantity marked on the detergent packaging for a small or delicate load rather than scaling up for the drum size.
Bleach is not appropriate for wool. Care label standards flag the do-not-bleach symbol specifically for wool garments , so stick to bleach-free detergents throughout.
Hand washing when the label requires it
If the label shows a hand-wash symbol rather than a machine-wash tub, the garment needs gentler treatment than any machine programme can provide. Woolmark describes the correct approach as lukewarm water around 30°C, with the garment allowed to soak rather than being rubbed or wrung . After rinsing first in lukewarm water and then in cold, press water out gently rather than twisting. Pull the garment back into shape before setting it aside.
Setting up a good flat dry
Once the wash cycle finishes, the garment is ready for flat drying. Spinning removes a useful amount of water and reduces drying time, but the appropriate spin setting for any specific garment should follow the care label rather than a general rule. The guide to drying wool garments on an autumn drying day covers location, surface choice and the reshaping steps once the garment is out of the machine. If you want to understand what the drying symbols on the label are telling you, the guide to reading drying symbols on a care label explains each one in plain terms.