How to wash wool without shrinking it

Wool shrinks from heat and rubbing, not from water. Keep it cool and keep your hands still, and a sweater comes out the size it went in.

By Nora VangSep 29, 20263 min read

A woman loading a camel sweater in a mesh laundry bag beside a front-loading washing machine

Most of the sweaters that reach our repairs counter shrunken were not washed too often. They were washed too warm, or rubbed while they were wet. Each wool fiber is covered in tiny scales. Heat opens them, friction locks them together, and once they lock they do not let go. That is felting, and it cannot be undone.

The good news is that wool needs washing far less than cotton. It resists smells and lets go of most dirt with a brush and a night by an open window.

Wash less

Air a sweater after each wear instead of washing it. Hang it over a chair back, not on a hanger, so the shoulders keep their shape. Brush off surface dirt with a soft clothes brush, and spot clean a small mark with cool water and a drop of wool wash. For a knit you wear twice a week, a proper wash every 6 to 8 weeks is plenty.

In the machine

A modern machine is gentler than most hands. Its wool cycle fills cold and rocks the drum instead of turning it, so the fibers barely rub. If the label allows a machine wash, use it.

Turn the sweater inside out and zip it into a mesh laundry bag, on its own or with 1 or 2 other knits.
Choose the wool cycle at 30 °C at most, with the spin at 600 or lower.
Use a wool wash. Ordinary detergents often carry enzymes that digest protein, and wool is protein.
Take it out as soon as the cycle ends. A wet knit left in the drum creases and stretches.

By hand

For cashmere, mohair, and anything labeled hand wash only, fill a basin with cool water and a little wool wash. Press the sweater under, leave it for 10 minutes, and rinse it in water at the same temperature. Do not swirl it or scrub it, and press the water out rather than wringing it.

Drying flat

Lay the sweater on a dry towel, roll the two up together, and press down along the roll to take out most of the water. Then unroll it onto a fresh towel, out of direct sun and away from the radiator. Pat it back to its own shape with your hands: square the shoulders, straighten the sleeves, ease the ribbing back in.

A camel merino sweater laid flat to dry on a white towel on a green table — Flat, on a towel, and smoothed back into shape. Turn it over once the top is dry.

A hanger stretches a wet knit by a size in an afternoon, and a tumble dryer shrinks it in 20 minutes. However you washed it, dry it flat.

If you would not put your hand in the water for a minute, do not put the sweater in it.

Nora Vang, at the repairs counter

And if it does go wrong, bring it in. We cannot unshrink a sweater, but we can tell you what happened, and a hole from a moth or a frayed cuff we mend for free.

Wash less

In the machine

A modern machine is gentler than most hands. Its wool cycle fills cold and rocks the drum instead of turning it, so the fibers barely rub. If the label allows a machine wash, use it.

Turn the sweater inside out and zip it into a mesh laundry bag, on its own or with 1 or 2 other knits.

Choose the wool cycle at 30 °C at most, with the spin at 600 or lower.

Use a wool wash. Ordinary detergents often carry enzymes that digest protein, and wool is protein.

Take it out as soon as the cycle ends. A wet knit left in the drum creases and stretches.

Drying flat

Flat, on a towel, and smoothed back into shape. Turn it over once the top is dry.

A hanger stretches a wet knit by a size in an afternoon, and a tumble dryer shrinks it in 20 minutes. However you washed it, dry it flat.

If you would not put your hand in the water for a minute, do not put the sweater in it.

Nora Vang, at the repairs counter

And if it does go wrong, bring it in. We cannot unshrink a sweater, but we can tell you what happened, and a hole from a moth or a frayed cuff we mend for free.