Do you know the feeling? Your favourite sweater that used to fit perfectly is now shrunk beyond recognition after you have washed it. Is it a conspiracy created by the textile industry to make you buy new clothes, or are other things at play? Let us look at what happens when wool shrinks and, not least, how to avoid it.
Why does wool shrink?
Wool, including cashmere, mohair, yak, alpaca, angora and others, shrinks when exposed to water, heat and mechanical movement. So all the conditions for the garment to shrink are present in your washing machine and tumble dryer.
A wool fibre is very similar to a human hair. If you take one of your own hairs and pull it between your thumb and forefinger, you will notice that it does not feel smooth both ways. This is because the hair is covered with tiny scales arranged like tiles on a roof. Wool fibres also have scales, and when they are processed in textile production, the scales act like hooks that lock the fibres together when they are spun into wool yarn. The heat from the washing machine and tumble dryer causes the scales to bind even more tightly to each other and clump together. The same thing happens when you felt wool.
Wool fibres are protein fibres, which is why modern detergents are not ideal to use, as they contain enzymes that are designed precisely to break down proteins. That is perfect if you need to remove food stains of grease and the like, but unfortunately they also break down the molecules in the wool's fibres.
Other factors that can play a part are the construction of the garment. Woollen-spun yarn, spun from short fibres, is not twisted as tightly and is more airy, and therefore tends to shrink more because of the larger surface area. Worsted-spun yarn, spun from longer fibres, is less airy with a smoother surface, which is why it shrinks less.
It can be difficult to identify which kind of yarn the garment is made of, but in general woollen-spun yarn is light and airy and is often used for thicker knitted textiles such as sweaters, hats and gloves. The stronger worsted-spun yarn is better suited to the thin, light woven textiles such as cashmere scarves and shawls.
Avoid shrinking your garment
Now that we know why wool garments shrink, we can look at how to avoid it. It is always a good idea to read the garment's washing instructions before washing, but in general wool garments can be washed. Always use a detergent intended for wool, as traditional detergents may contain enzymes that are not good for the wool. Wool detergent can be bought online or in many clothing shops that sell garments of fine wool and cashmere.
Always wash the garment in cold water - max. 30 degrees. If you have a modern washing machine with a dedicated wool programme, this will often be preferable to hand washing. Partly because it can be difficult to rinse the detergent out properly by hand, but the machine also presses more water out of the garment during the spin, which reduces the drying time. If the garment takes too long to dry it can start to smell bad and even become musty. Never put wool in the tumble dryer!
Getting stubborn stains washed out in a cold wash can be a problem. Therefore, pre-treat stains on the garment with a detergent or stain remover intended for wool before washing. Read the instructions before using it so you know how much to apply and how long it should work.
Dry cleaning can also be an option, but in general my impression is that many people send their clothes to the cleaners without it really being necessary. If your garment is simply creased, steaming will be more than enough to remove folds and creases. If your wool garment is not actually dirty but just smells of smoke or perfume, it is enough to air the garment outdoors overnight. Your garment will last longer and you spare the environment.
How to save a shrunken wool sweater
If the damage is done and your wool sweater or cashmere cardigan has shrunk to a child's size, you can try to save it with the method below. We have tested it, and it is actually possible to stretch the garment back to its original size. It may be necessary to repeat the process a couple of times.
- Fill a basin with lukewarm water and add 1 dl of hair conditioner, dissolved in the water.
- Soak the sweater in the water for about 10 minutes.
- Gently wring the sweater so that most of the water comes out, and lay it flat on a towel.
- Roll the towel up to press more water out of the sweater.
- Then place the sweater on a dry towel and stretch it back into shape.
- Now let the sweater dry flat on the towel.
The conditioner makes the wool fibres relax, and it therefore becomes possible to stretch the garment out to its original shape and size. Avoid stretching the garment too hard, as it may otherwise lose its shape, so pull gently in both the length and the width of the garment.
Avoid the problem in the first place
To avoid shrinking your wool garment, it is important to use a detergent intended for wool. In our range of care products we have a number of plant-based detergents for wool garments and silk. They are completely free of chemicals, and are gentle on both your garment and the environment.