How to wash a sweater without shrinking it
How to wash a sweater without shrinking it: why wool felts, hand and machine wash steps, how to dry flat, care for synthetic knits and how to store sweaters.
You put your favorite sweater in the wash and it came out two sizes smaller. It happens to almost everyone once. The fix is mostly about three things: heat, rubbing and how you dry it. Here is what actually causes shrinking and how to wash a sweater safely, whatever it is made of.
Why do sweaters shrink?
For wool, it is a process called felting. A University of Wisconsin Extension explainer on the science of felting describes it simply: each wool fiber is covered in tiny scales. Hot water makes the scales lift, and rubbing or agitation makes them catch and lock onto each other. The fibers pack tighter and the fabric shrinks. The same source notes that felting cannot be undone, which is why prevention is everything.
Wool that has been treated so its scales stay flat resists felting, which is why some wool sweaters are labeled machine washable. Woolmark notes that a machine washable wool garment can be washed multiple times without shrinking.
Step one: read the care label
The label tells you whether a sweater can go in the machine, how warm the water can be and how to dry it. It is your best guide, so start there. If it says dryclean only, the Drycleaning and Laundry Institute advises taking it to a drycleaner, stains included.
How do you hand wash a sweater?
Hand washing gives you the most control. This combines Woolmark's steps for wool with the American Cleaning Institute's general sweater advice:
- Fill a basin with clean water. Woolmark suggests lukewarm water for wool. The American Cleaning Institute says use cold water when you are unsure.
- Add a detergent made for wool or delicates.
- Submerge the sweater and let it soak. Woolmark suggests about 10 minutes.
- Swish it gently. Do not rub or twist. The American Cleaning Institute stresses this.
- Rinse thoroughly. Woolmark rinses in lukewarm water, then again in cold.
- Do not wring. Roll the sweater in a clean towel and press to remove water.
Can you machine wash a sweater?
Only if the care label allows it. Then, Woolmark suggests turning the sweater inside out or using a laundry bag, choosing a wool detergent, and selecting the wool cycle. If your machine does not have one, use a cold or delicates cycle. The American Cleaning Institute also notes that some washers have a hand wash cycle.
How do you dry a sweater so it does not shrink?
Flat. The American Cleaning Institute says hand wash only sweaters should be dried flat, and Woolmark says to lay knitwear flat to dry in the shade, away from direct sunlight. The Drycleaning and Laundry Institute adds: away from direct heat.
- Lay a dry towel on a flat surface or a drying rack.
- Shape the sweater to its original size, smoothing the sleeves and hem.
- Tip from the American Cleaning Institute: trace the sweater on paper before washing, then use the tracing to reshape it while it dries.
- Flip it once so both sides dry evenly.
How do you wash a synthetic sweater?
Polyester and acrylic knits do not felt like wool, but they are not heat proof. The Drycleaning and Laundry Institute explains that acrylic is a thermoplastic, so heat can affect it, and advises avoiding high temperatures in drying or steam pressing. Lay flat to dry, or tumble on low only if the label says so.
Our Cable Sleeve Turtleneck Sweater is a 100% polyester knit, and its care is simple: hand wash cold, lay flat to dry. That is the same gentle routine above, just with cold water. If you have the turtleneck from The Winter Layers Set, wash it on its own or with similar colors, rather than with heavy jeans.
How should you store sweaters?
- Wash before storing. The American Cleaning Institute warns that some soils attract insects and hidden stains can darken over time.
- Fold, do not hang. Hanging can stretch the shoulders out of shape.
- Store somewhere cool, dark, dry and ventilated. Skip plastic bags.
- Mind your jewelry. Loose knits snag easily.
Sweater washing recap
- Check the label first.
- Cool water, gentle detergent, no rubbing or twisting.
- Machine only if the label allows it, on a wool or delicate cycle.
- Towel, then dry flat away from heat and sun.
- Fold to store.
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Questions
Why do sweaters shrink in the wash?
Wool fibers are covered in tiny scales. A University of Wisconsin Extension explainer says hot water lifts the scales and rubbing makes them lock together, so the fabric packs tighter and shrinks. That felting cannot be reversed.
What water temperature should I wash a sweater in?
Follow the care label. The American Cleaning Institute suggests cold water when you are not sure, and Woolmark recommends lukewarm water and a wool detergent for hand washing wool.
Can you put a sweater in the dryer?
Hand wash sweaters should be dried flat, according to the American Cleaning Institute. Some machine washable sweaters can go in on low heat, but only if the care label says so.
Do synthetic sweaters shrink?
Synthetics do not felt like wool, but heat can still change them. The Drycleaning and Laundry Institute notes that acrylic is heat sensitive and advises avoiding high temperatures in drying or steam pressing.
Should I hang or fold sweaters?
Fold them. The American Cleaning Institute says hanging can stretch sweaters out of shape.
Keep reading
Sources: Woolmark: how to wash a wool sweater · American Cleaning Institute: sweater care · Drycleaning and Laundry Institute: sweaters and their many fibers · University of Wisconsin Extension: the science of felting