How to Unshrink a Cashmere Sweater

The short answer

Press out water gently between two towels, reshape the garment while it is still damp, then lay it flat and gently stretch it back to its original size while it is still damp. Leave it flat to dry completely.

Why cashmere shrinks

Cashmere shrinks because of heat and agitation. The natural fibres have tiny scales along their surface. When exposed to warm or hot water those scales open up. When agitation is added, tumbling in a dryer, vigorous hand washing, or a rough machine cycle, the open scales lock together and the fibre shortens and tightens. This process is called felting.

Mild shrinkage happens when the fibres tighten slightly without fully felting. This is reversible. Severe felting, where the fibres have completely bonded together and the fabric has become dense and stiff, is much harder or impossible to reverse fully.

The good news is that most accidental shrinkage falls into the mild to moderate category, and the method below works well in those cases.

Will it work on your sweater?

Before you start, check the fabric to get an honest sense of what to expect.

Recovery outlook

• Good chance of recovery: fibres tightened but not felted; the sweater is smaller but still soft and pliable; the knit stitch pattern is still visible.

• Partial recovery only: fabric is dense, stiff or matted; the sweater feels thick and the individual knit stitches are no longer visible.

Significant felting has occurred in the second case. Some improvement is possible but the sweater may not return fully to its original state.

What you will need

Care kit

• A clean sink or basin large enough to fully submerge the sweater
• Cool or lukewarm water
• Hair conditioner, fabric conditioner, or baby shampoo
• Two clean dry towels
• A flat surface to reshape the garment on
• A tape measure if you know the original dimensions

The conditioner is the key ingredient. It softens the cashmere fibres and makes them more pliable, which allows you to stretch the garment back towards its original shape without causing damage.

Step by step method

1. Fill the basin with cool water

Use cool or lukewarm water, not cold and not warm. You want the water at a temperature that is comfortable to hold your hand in without feeling hot. Hot water is what caused the shrinkage in the first place.

2. Add conditioner and mix

Add two to three tablespoons of hair conditioner or fabric conditioner to the water. Swirl it through until evenly distributed. Baby shampoo also works well if you do not have conditioner.

3. Submerge and soak for 20 to 30 minutes

Place the sweater into the water and press it down gently so it is fully submerged. Do not agitate or scrub. Just let it soak. The conditioner needs time to penetrate and relax the fibres before they can be stretched.

4. Gently squeeze out the water

Lift the sweater out supporting it from underneath with both hands. Press it gently against the side of the sink to remove excess water. The sweater will still be quite heavy and wet at this stage, which is fine.

Never wring or twist the fabric. This causes permanent distortion and makes recovery much harder.

5. Press between two dry towels

Lay a dry towel flat, place the sweater on top, and lay a second towel over it. Press down firmly across the entire garment to absorb water. Rolling the towels together and pressing along the roll removes even more moisture. You want the sweater damp, not soaking, before you start stretching.

6. Stretch gently back to size

Lay the sweater flat on a clean dry surface. Working slowly and section by section, use both hands to gently pull and ease the fabric back towards its original dimensions. Start at the shoulders, then work down the body and along the sleeves. Apply even pressure across the width rather than tugging at a single point.

Pull the fabric slightly further than you need to. It will contract a little as it dries, so stretching slightly beyond the target size gives you a more accurate final result.

7. Reshape and leave to dry completely flat

Smooth the sweater into its correct shape and leave it flat to dry. Do not hang it. Check on it every few hours while it is still damp and gently re-stretch any areas that have pulled back in. Once the sweater is fully dry the shape will be set. This usually takes 12 to 24 hours depending on the knit thickness.

How many times can you repeat the process?

If the first treatment does not recover the full size you can repeat the soak and stretch process. Each round of conditioning and stretching can gain a little more back.

Do not repeat more than three times. Repeated soaking and stretching can eventually weaken the cashmere fibres even when done gently.

How to prevent cashmere from shrinking

The easiest way to deal with shrinkage is to stop it from happening in the first place.

Prevention rules

• Always wash in cool water: warm or hot water is the primary cause of shrinkage in cashmere.

• Never use the tumble dryer: even a low heat or air-only setting generates enough heat and movement to cause shrinkage and felting.

• Use a wool or delicate machine cycle: these cycles use minimal agitation and shorter wash times.

• Turn inside out before washing: this reduces surface friction and protects the outer fibres from agitation and pilling.

Frequently asked questions

Does the conditioner method always work?

It works well for mild to moderate shrinkage where the fibres have tightened but not fully felted. For severely felted cashmere where the fabric has become dense and stiff, the results are less predictable. Some improvement is usually possible but full restoration may not be.

Can you use any conditioner or does it need to be a specific type?

Most standard hair conditioners work well. Look for something moisturising without strong fragrances or colourants. Fabric conditioner also works. Baby conditioner is a particularly gentle option. Avoid clarifying conditioners, which can strip fibres rather than soften them.

Will the sweater shrink again after unshrinking?

If you wash it again in warm water or put it in the dryer, yes it will shrink again. The unshrinking process does not change the fundamental properties of the fibre. You need to continue washing in cool water and drying flat to prevent it from shrinking again.

How long should you soak it for?

At least 20 to 30 minutes. For more stubborn cases you can soak for up to an hour. The longer soak gives the conditioner more time to penetrate the fibres and relax them before you begin stretching.

Can you unshrink a cashmere blend?

It depends on the blend. A cashmere and wool blend generally responds well to the same method. A cashmere and synthetic fibre blend may be more resistant. The cashmere fibres themselves will respond to conditioning, but the synthetic fibres may limit how much the overall garment can be stretched.

Can a dry cleaner fix a shrunken cashmere sweater?

Some specialist dry cleaners and knitwear restoration services offer professional blocking, using specialised frames and steam to stretch and reshape knitwear. This is worth looking into for a beloved or expensive garment that has shrunk significantly and has not responded fully to home treatment.

How can I tell if cashmere has felted beyond repair before treating it?

Feel the fabric. If it is still soft and the knit structure is still visible, the fibres have tightened but not fully felted and you have a good chance of recovery. If the fabric feels thick, dense, and matted and the individual knit stitches are no longer visible, significant felting has occurred and recovery will be partial at best.

The bottom line

A shrunken cashmere sweater is not necessarily a lost cause. In most cases a soak in cool water with conditioner followed by careful stretching and flat drying can bring the garment back close to its original size.

The method works best when the shrinkage is caught early, the fibres have not fully felted, and the stretching is done gently and evenly. Do not rush it, do not use heat, and do not wring the fabric at any point.

Going forward, cool water and flat drying are the two habits that will protect your cashmere from ever shrinking again.