How to unshrink wool (and how to shrink it)

Wondering how to shrink wool or how to fix a shrunken wool sweater? Whether you’re shrinking or unshrinking wool, follow our simple guide.

Updated 2 October 2023


AuthorBy Cleanipedia Team

Reading Time5 minutes

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Wool’s a great material. It’s cosy, it’s comforting, it’ll keep you warm in the autumn and winter. It’s also prone to shrinking, which is great if you want to know how to shrink wool, but not so great when you’re frantically Googling ‘how to unshrink merino wool sweater’. Here’s our guide to both how to shrink and how to unshrink a wool jumper or any other woollies that are giving you trouble.

Why does wool shrink?

Wool is a natural fiber that has a tendency to shrink when exposed to certain conditions. The main reason for wool shrinkage is the presence of heat, moisture, and agitation. When wool fibers are subjected to these factors, they can interlock and become tightly packed together, resulting in the fabric shrinking. Additionally, the scales on the surface of wool fibers can latch onto each other, further contributing to shrinkage. To prevent shrinking, it's important to follow the care instructions for wool garments, such as washing them in cold water, avoiding excessive agitation, and laying them flat to dry.

Key Steps

If you want to know how to shrink or how to unshrink wool:

  • To shrink, agitate the wool in a warm environment, either by hand or in a tumble dryer.

  • To unshrink, relax the fibres with fabric conditioner so you can stretch the wool out by hand.

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  • How to shrink wool sweater by hand

    Be careful when you’re shrinking wool. It’s easy to make it a little too small or felt it by accident. You might prefer to do your shrinking by hand, so you can keep an eye on the process.

    1. 1

      Use a wool-friendly detergent.

      Put a few drops of a wool-friendly detergent into a basin of warm water.

    2. 2

      Use a basin.

      Put the item you’re hoping to shrink in the basin.

    3. 3

      Gently swish the item round.

      Every two minutes, gently swish the item around in the water for a few seconds, then check to see how it’s looking.

    4. 4

      Use a towel.

      When you think it’s shrunk enough, take the item out and press the excess water out of it with a towel.

    5. 5

      Leave it flat.

      Lay the item on a fresh towel, keeping its shape, and leave it flat to dry. Keep it away from radiators and direct sunlight, or it might shrink more than you wanted!

  • How to shrink a wool jumper in the tumble dryer

    A lot of wool items have the ‘do not tumble dry’ symbol on their care label. There’s a reason for that: being spun around in the heat makes wool shrink, and the care label assumes that’s not your goal. If you want to know how to shrink wool, of course, it’s good news. 

    To machine-shrink wool:

    1. 1

      Dampen the item.

      Make sure it’s equally damp all over if you want it to shrink evenly.

    2. 2

      Use a tumble dryer.

      Put it in the tumble dryer and set the heat to medium.

    3. 3

      Keep your eyes on it.

      Every four or five minutes, take a look to see how it’s doing.

    4. 4

      Act quickly.

      Take it out as soon as it looks like it’s shrunk enough.

  • How to un-shrink a wool sweater

    What if your shrinking efforts go awry, or a regular wash has unwanted results? Can you unshrink a wool jumper?

    Unshrinking clothes is never guaranteed to go perfectly, but it’s worth a shot. If the item has already shrunk, there’s no harm in seeing if you can salvage it. Here’s a method for how to fix a shrunken wool sweater or any other item made of wool.

    1. 1

      Use fabric conditioner.

      Mix some fabric conditioner, such as Comfort Intense Fresh Sky into warm water. Use a container that’ll fit your jumper (or whatever other woollen items you’re hoping to unshrink). About two tablespoons are enough for a regular sink.

    2. 2

      Soak it!

      Soak the item in the solution for 15 minutes.

    3. 3

      Use a towel.

      Gently press excess water out of the wool with a towel.

    4. 4

      Stretch it.

      Lay the item flat on a dry towel. Stretch it carefully into the shape and size you want.

    5. 5

      Leave the item as it dries.

      Leave the item as it dries. Every hour or so, check on it and stretch it out again if it’s drawing back into itself.

How to Unshrink Wool with Salt

Start by filling a sink or tub with lukewarm water. It’s important to use water that is not too hot, as hot water can shrink the wool fibres further. Add a tablespoon of salt for every litre of water used. Place the shrunken wool garment into the saltwater solution. Gently agitate the water, with your hands, to make sure that the saltwater is evenly distributed, and that the wool absorbs it. Allow the wool to soak in the solution for at least 30 minutes - the longer, the better. The saltwater will help to relax the wool fibres, making them less tense and easier to stretch. Remove the wool garment from the water and carefully squeeze out the excess moisture. Then, place it onto a flat, clean towel. Stretch the wool garment back to its original shape. Gently tug and pull it into the desired shape, making sure that you don’t pull too hard as this could damage the wool fibres. Your garment should be damp, but not soaking wet at this point. Leave the garment to dry on a flat surface, carefully reshaping it as it dries. This may take a few hours or even a whole day, depending on the size of the item. It’s essential to leave it to dry naturally, as machine drying can cause the wool fibres to shrink again.

How to Care for Wool Clothing

Caring for wool clothing requires a delicate approach to maintain its quality and longevity. Start by reading care labels for specific instructions. Hand wash in cool water with a mild detergent, avoiding harsh agitation. Gently squeeze water out without wringing. To prevent stretching, lay flat on a towel to air dry. Use a steamer or iron on low heat to remove wrinkles. Store in a cool, dry place with proper ventilation, preferably folded to prevent stretching on hangers. Regularly brush off any surface debris. With mindful handling and occasional professional cleaning, your wool garments can remain soft, warm, and stylish for years.

This can even be used as a method for how to unshrink merino wool. Now that you know how to shrink and how to unshrink wool, you might be wondering how to deal with other materials. Never fear! We have more general guides on how to shrink clothes and how to unshrink clothes, for all your sartorial sizing adjustments!

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