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How To Unshrink Woollen Jumpers

We’ve all been there – you have a beautiful woolly jumper that needs a wash and after a while, you realise it just doesn’t fit the way it used to. This might be immediately after washing it or it might be that it’s gradually shrunk over the course of several washes. What usually happens is you part with it – either by passing onto someone you know who it’ll now fit or donating it to charity. But what if you didn’t have to part with your shrunken jumpers? What if there was a way to unshrink them back to the size they should be?

Some years ago, before I knew anything at all about yarn, I asked my mother in law to knit a jumper for me. My last good one had shrunk to the point it had become unbearably small on me and (as I have rubbish circulation) I get cold easily, so I wanted something to replace the jumper I could no longer wear. I picked the pattern and deliberately chose some merino wool which had been superwash treated, thinking this might help to prevent shrinkage. I’ll discuss superwash wool in another post in the future, but let’s just say that it doesn’t prevent your woollens from shrinking.

I pretty much live in my jumpers from autumn to spring and I only wash them when they really need it, but even this didn’t stop my gorgeous jumper from gradually getting smaller and smaller. Only when I tried to wear it again around this time last year did I realise that my once hip-length jumper was now becoming a crop top. The sleeve cuffs barely reach my wrists anymore. Not exactly ideal. I couldn’t bear to part with it though, so I put it away in storage, hoping to find a solution. Then I learned you can unshrink jumpers.

Here you can see just how much my jumper has shrunk - it used to be the same length as the long sleeve tshirt I'm wearing underneath

How exactly do you unshrink jumpers?

I first learned about unshrinking jumpers from an advert for a Country Living article. Now they’re assuming you’ve shrunk the jumper from putting it in the dryer, which can occasionally happen, but I think it’s more likely to happen from simply washing it. If you knit or crochet jumpers a lot, you probably have a blocking mat and you can use this, though as I don’t have one I’ll be using towels.

Step 1

Fill a sink with barely warm water – and I mean barely warm. Wool is prone to fibre shocking if you try and put it in water which is too warm too quickly, causing it to felt (go really fuzzy and difficult to work with) and/or shrink. The heat of the water when you washed it is what likely caused your jumper to shrink in the first place.

Step 2

Add some gentle shampoo or conditioner to the sink to help unshrink your jumper
I added a teaspoon of hair conditioner to the sink (and yes I did check, it was PH balanced)

Add a little bit of a super gentle shampoo or conditioner (we’re talking baby shampoo or PH balanced conditioner) to the water. Alternatively you could order some wool specific solutions, like a scouring treatment (usually used before dyeing yarn) or a PH neutral soap solution to use.

When I say a little bit, you want around a teaspoon’s worth. Mix it in the water until you get a few small bubbles appearing.

Step 3

Add your jumper carefully to the water and fully immerse it. You might have to hold it under for a few seconds for any air to escape and to allow the fibres to get properly wet. Leave it to soak in the water for 10 minutes.

Do not scrub or move the jumper around when it’s in the water, as this can accelerate felting.

Step 4

Drain the sink after 10 minutes. Don’t wash the jumper with clean water, just very gently squeeze the excess water out. Don’t be tempted to just wring it out as you’ll damage the fibres. The point of leaving the jumper to soak was to allow the fibres to relax and open up a little (this is why conditioner works, as it does the same thing to your hair).

Step 5

Rolling your jumper in a towel helps to gently squeeze excess water out of it
I used a bath sheet folded in half to help absorb more water and carefully rolled it up from right to left

Carefully transfer the jumper to a towel which has been laid out on a flat surface. Lay it flat on the towel and slowly, gently roll the towel up. This will help to squeeze out and absorb excess moisture without damaging the fibres.

Don’t keep it rolled up for long, you want to only roll it long enough to get rid of the excess water. When you unroll the towel, the jumper should be damp – not dripping wet like it was before this step.

Step 6

Using a tape measure helps you know when you've stretched your jumper back to its original size
Using a tape measure helps you know when you've stretched your jumper back to its original size. Always use the underarm to measure from too, as this is how most jumpers are measured when you knit or crochet them

Transfer the jumper to a dry towel – again on a flat surface. Carefully stretch the jumper out to its original size and allow it to dry flat on this surface (or another if you need to – just make sure it stays flat and the right size). If you can, weight it or pin it in place to help it stay in shape and try to keep it away from any hot radiators while it dries.

This is the step where those with a blocking mat will be able to use it – after all, blocking mats were designed for precisely this kind of use. As with the towel method, carefully stretch the jumper to its original size and pin it in place while it dries.

If your jumper has shrunken by quite a bit (say going from adult sized to child sized), you might have to repeat the above steps several times to gradually unshrink it. Yes it’ll take time, but if you’re patient, you should still be able to slowly get it back to its original size.

Voila – one unshrunken jumper!

You can see my jumper is back to its normal size and I can keep wearing it, which makes me very happy! (The middle is designed to be a little shorter, this is how it looked before it shrank).

Extending the life of your jumper

It’s probably best to keep an eye on the size of your jumper any time you wash it after you’ve unshrunk it, just to make sure the fibres aren’t contracting and shrinking again. Wherever possible, try and dry it flat so that you can carefully stretch it out again if you notice it getting a bit small. As animal wool is naturally resistant to microbes and bacteria, you shouldn’t need to wash your jumpers that often anyway since they won’t get smelly. You should only really wash jumpers when they’re actually dirty, though more often than not you may be able to spot clean just the area which needs it. This is something I’ve come to understand as I’ve learned more about the best ways to look after clothes and extend their useable lives, so I’ll definitely try to spot clean my jumpers more and wash them less.

When storing woolly jumpers, it’s also best to keep a little pouch of lavender with them. Lavender is naturally insect repelling and so it’ll help to keep your woollens safe from moths and other creatures which might otherwise make a meal of your jumper. It won’t impart a strong smell like cedar mothballs do, instead it’ll just make your woollens smell fresh.

Should any holes occur at all – whether from insects or from wear and tear – you can also darn and mend wool easily enough. A few years ago, my mother in law used a bit of leftover wool to mend a small hole that had appeared in the cuff of my jumper – as it was the same wool the jumper was made from, it’s an invisible mend, though you can use whatever colour you like if you want to make a visible mend. Both The Endery and Ministry of Mending have darning kits, yarns and looms to help you mend your clothes quickly and easily.

Hopefully this will help you unshrink and look after your favourite jumpers, rather than passing them onto someone else to enjoy instead!