Can wool be machine washed?

Yes, if the label allows it, using the machine's wool program. This program limits the temperature and the drum movement. A laundry bag adds protection for the knit.

Why does a wool sweater shrink?

Wool fiber is covered with tiny scales. Under the effect of heat, moisture and friction, these scales interlock and the knit tightens: this is felting. The sweater shrinks and hardens, with no way back.

How to Wash Wool Without Damaging It

Q: How to wash wool without damaging it?

To wash wool without damaging it, use cold or lukewarm water, at 30 °C at most, with a wool-specific detergent, limiting friction and spinning. Drying is done flat, on a towel, away from a heat source. Heat combined with friction causes felting, which is irreversible.

In short:
Wool is washed at 30 °C at most, with a suitable detergent.
Felting comes from the combination of heat, moisture and friction.
Drying is always done flat, never in the tumble dryer unless stated otherwise.
Airing a sweater between wears reduces the number of washes needed.

Why wool needs precautions

Wool fiber is covered with microscopic scales. When it is heated, wetted and rubbed at the same time, these scales interlock and the knit tightens. This felting is irreversible. Knowing how to wash wool therefore comes down to avoiding these three factors together.

The right steps

Before washing

Read the label: some pieces are dry clean only. The composition also indicates whether it is pure wool or a blend, as explained in the article on clothing labels and manufacturing.

Washing

Step	Do	Avoid
Temperature	Cold to 30 °C	Hot water
Detergent	Wool-specific, enzyme-free	Standard detergent
Movement	Wool program or hand washing	Rubbing the knit
Spinning	Press in a towel	Wringing the garment

Drying

Lay the piece flat on a dry towel, reshaping it. A hanger distorts the shoulders of a wet sweater.

Washing less often

Wool naturally resists odors. Airing a sweater overnight is often enough. This is one of the habits that make timeless wardrobe essentials last. For other fabrics, the guide to linen, cotton or viscose gives care benchmarks.