How to wash a wool or merino jumper

A wool or merino jumper can go in the washing machine where its care label says it can. The machine wool cycle runs at around 40 degrees Celsius. Hand washing uses cooler water, around 30 degrees. Both figures come from The Woolmark Company, and they are not in conflict.

Can a wool jumper go in the machine

The care label on the garment is the final word. A machine washable wool symbol means the jumper can be washed in a machine, and the symbol shows a temperature of 40 degrees Celsius, or sometimes 30 degrees Celsius with a very mild wash. The Woolmark Company adds that a sew in label reading machine wash means the garment can be machine washed multiple times without shrinkage.

One rule tends to get missed. Reduce the quantity of laundry so the drum is no more than one third full, which is Woolmark's own instruction for the very mild wash cycle.

Reading the care label

The care symbols carry more detail than most people read. A hand wash symbol means the garment should be washed by hand rather than in a machine. A do not wash claim means the article must not be washed at all, which Woolmark notes can be because it is sensitive to any kind of wet treatment, or simply because of its size.

The triangle with a diagonal cross means bleaching is not allowed. For ironing, Woolmark gives a maximum sole plate temperature of 150 degrees Celsius, the wool setting, under a moderately moist intermediate cloth. A steam iron can be used. Avoid heavy pressure. These symbols are owned by GINETEX and used under licence.

The machine wool cycle, step by step

These steps follow The Woolmark Company's published guidance.

• Check the label for the machine washable wool symbol.
• Turn the jumper inside out, or place it in a laundry bag.
• Set the machine to the wool cycle. Where a machine has no wool cycle, use the cold water wash or the cycle for delicates.
• Use a neutral, mild detergent, preferably one Woolmark recommends.
• Reduce the amount of laundry so the drum is no more than one third full.

Hand washing a wool or merino jumper

Where the label shows a hand wash symbol, The Woolmark Company gives a water temperature between 30 degrees Celsius and a maximum of 40 degrees Celsius, depending on the article.

• Fill a clean basin with lukewarm water, approximately 30 degrees Celsius.
• Dissolve a fine wool detergent in the water before adding the garment.
• Submerge the jumper and let it float. Agitate carefully without rubbing, pulling or wringing.
• Soak for 10 minutes.
• Rinse thoroughly in lukewarm water, then rinse again in cold water.
• Press the surplus water out carefully. Do not wring.
• Pull the jumper gently back into shape and move it to a towel for drying.
• Do not leave the garment lying in a wet state.

Drying without stretching the shape out

Knitwear such as jumpers should be dried flat, unless the garment's care claim states it can be tumble dried. The Woolmark Company explains why hanging a wet jumper is a problem: the weight of the moisture stretches the knit, so the garment grows in length and loses its shape. Place the jumper on a pale coloured or white towel that is free from lint, then gently knead it by hand into shape and size, removing as many creases or folds as possible. Garment drying mesh screens designed to fit over a bathtub are also available and tend to speed up drying.

Each merino wool fibre behaves like a coiled spring that returns to its natural shape, as Woolmark describes it, which is why reshaping a damp jumper works at all. Avoid direct sunlight, sunlight magnified through a window, and direct heat. Never dry a wool garment over a radiator: the part folded over the top dries quickest, which can change the garment's colour or damage it in that area. Any pins used to hold the garment in shape must be rust proof.

Tumble drying, and when it is allowed

The common advice never to tumble dry wool is not what the industry body actually says. Woolmark states that certain wool garments can safely be tumble dried without shrinking. Where the care claim on the garment says tumble dry, use a low heat setting or a setting for wool or delicates, and Woolmark advises using a tumble dryer it has approved. A garment whose label does not say tumble dry should be flat dried instead.

How often wool actually needs washing

Wool requires less washing than other fibres. It is naturally stain resistant, odour resistant and crease resistant. Knit-On house brand knitwear is usually made from superfine 18.5 micron Australian merino wool. Across the range there are 76 styles in Women's Merino Jumpers, from $99 to $499 AUD, and 65 styles in Men's merino, from $79 to $249 AUD.

Cashmere has its own washing method rather than this one, set out in How to wash cashmere without ruining it. Where small fuzzy balls have appeared on the surface, that is pilling, and Why knitwear pills and how to fix it covers the cause and the fix.

Common questions

Can you put wool jumpers in the washing machine?

Only where the care label says you can. A jumper carrying the machine washable wool symbol can go in on the wool cycle. A label showing a hand wash symbol, or a do not wash claim, keeps the garment out of the machine.

Does 100% wool shrink in the wash?

It can shrink when washed against the label. A sew in label reading machine wash means the garment can be machine washed multiple times without shrinkage, which is The Woolmark Company's own wording.

What temperature should I wash a merino jumper at?

Machine wash on the wool cycle, which runs at around 40 degrees Celsius. Hand wash in lukewarm water at approximately 30 degrees Celsius. Both are Woolmark figures for their respective methods, and the garment's own care label overrules either one.

How often should a wool jumper be washed?

Less often than a garment in most other fibres. Woolmark describes wool as naturally stain resistant, odour resistant and crease resistant, which is the reason it needs washing less frequently.