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Insight · Wool Care
How to Wash a Wool Sweater Without Shrinking It
The short answer
To wash a wool sweater without shrinking it, use cold or lukewarm water, a wool-safe detergent with no enzymes or bleach, and as little agitation as possible. Hand wash it in a basin, or turn it inside out and run it on your machine's wool or delicate cycle with a slow spin. Never put it in the dryer.
Press the water out in a towel, reshape it, and dry it flat. Wool shrinks from heat and rubbing together, not from water alone. Keep both away and your sweater keeps its size.
Most shrunken sweaters die the same way. They go in the regular wash with the jeans, get a warm cycle and a hard spin, and finish in a hot dryer. They come out a size smaller, stiff, and thick as a felt hat. It happens to everyone once.
It does not need to happen twice. Wool is one of the easiest fibers to care for when you know the two rules: keep it cool and keep it still. This guide covers hand washing, machine washing, drying, what to do if the damage is already done, and how often a sweater actually needs a wash. It applies to our wool sweaters and to most wool knits you already own.
Why wool shrinks: heat plus agitation
Each wool fiber is covered in tiny overlapping scales, a little like shingles on a roof. When wool gets warm and wet, those scales lift. When the wet fibers are then rubbed, tumbled, or wrung, the scales hook into each other and lock. The fibers pull tighter and tighter, and they do not let go. That process is called felting, and it is permanent.
So the enemy is not water. It is heat and agitation working together. A cold soak in a still basin does almost nothing to wool. A hot cycle followed by a tumble dryer can take a sweater down a full size in an hour.
Read your care label first. Our Crewneck and Quarter Button sweaters are wool blends. Some wool, some cashmere, and some blends say hand wash only, and some say dry clean. The label sewn into your sweater is the final word. Everything below is the gentle method that suits most wool knits.
How to hand wash a wool sweater
Hand washing is the safest method, and it takes about fifteen minutes of actual work. Here is how we do it.
- Fill a clean basin or sink with cool or lukewarm water. It should feel neutral on your wrist, never warm. Add a small amount of wool-safe detergent and swish it to dissolve before the sweater goes in.
- Turn the sweater inside out and submerge it. Press it gently under the water until it is soaked through.
- Let it soak for about 10 to 15 minutes. Do not scrub, twist, or rub. If there is a spot, press the fabric gently between your fingers.
- Drain and rinse in water of the same temperature. A sudden change from warm to cold can shock the fibers. Press the sweater against the side of the basin to push the soap out. Repeat until the water runs clear.
- Press out the water. Do not wring. Squeeze the sweater in a ball, then lay it flat on a dry towel, roll the towel up like a sleeping bag, and press down along the roll.
- Reshape and dry flat. Unroll it onto a fresh dry towel or a flat drying rack, square up the shoulders, straighten the ribbed cuffs and hem, and leave it out of direct sun and heat.
How to machine wash a wool sweater
If your label allows machine washing, a modern washer can be gentler than you would think. The key is choosing the right cycle.
- Use the wool or hand wash cycle if your machine has one. If not, use the delicate cycle.
- Set the water to cold. Never warm or hot.
- Use the lowest spin speed. A hard spin crushes wet wool against the drum.
- Turn it inside out and put it in a mesh laundry bag. This cuts down on rubbing against the drum and other clothes.
- Wash it alone or with a few other soft knits. Jeans, canvas, and anything with zippers or hooks will rough it up.
- Take it out the moment the cycle ends and dry it flat as above. Do not leave it balled up wet in the drum.
Hand wash vs. machine wash at a glance
| Step | Hand wash | Machine wash |
|---|---|---|
| Water | Cool or lukewarm, same temperature for wash and rinse | Cold |
| Cycle | Still soak, 10 to 15 minutes | Wool, hand wash, or delicate cycle |
| Spin | None. Press water out in a towel | Lowest setting |
| Protection | Turn inside out | Inside out, in a mesh bag |
| Detergent | Wool-safe, no enzymes, no bleach | Wool-safe, no enzymes, no bleach |
| Drying | Flat on a towel or rack | Flat on a towel or rack |
| Risk of shrinking | Lowest | Low, if the settings are right |
What water temperature and detergent to use
Water: cold or lukewarm, and the same temperature from start to finish. If it feels warm to your hand, it is too warm for wool. The rinse matters as much as the wash, so do not switch from a lukewarm soak to an ice-cold rinse.
Detergent: use a detergent labeled for wool or delicates. Most everyday detergents contain enzymes, often protease, that are made to break down protein stains. Wool is a protein fiber, so those enzymes can weaken it over time. Skip bleach entirely; chlorine bleach damages wool and can yellow it. Use a small amount, since leftover soap leaves wool stiff and attracts dirt.
How to dry a wool sweater and keep its shape
Drying is where most of the damage happens, so slow down here.
- Never use the dryer. Not even on low. Heat plus tumbling is the exact recipe for felting.
- Never hang it wet. The weight of the water will pull the shoulders and body long, and hanger points will stretch the neck.
- Dry it flat. A mesh sweater rack is ideal because air reaches both sides. A dry towel on a table works too. Flip it once and swap the towel if it gets soaked.
- Reshape while damp. Pat the body square, line up the side seams, and ease the cuffs and hem back to size. Wet wool will hold the shape you give it as it dries.
- Keep it out of direct sun and off radiators. Gentle room air is plenty. A midweight sweater usually needs a day or two to dry fully.
What to do if your wool sweater already shrank
If a sweater came out a little small and a little stiff, there is a home method that may help relax the fibers enough to stretch some of the size back. It works best on mild shrinking. A sweater that has fully felted, thick and matted with no visible stitches, usually will not come back.
- Fill a basin with lukewarm water and stir in a generous amount of plain hair conditioner or baby shampoo, roughly a tablespoon per liter of water.
- Soak the sweater for 15 to 30 minutes. The conditioner may help the fibers relax and slide past each other.
- Press out the water without rinsing, then roll it in a towel to remove more.
- Gently stretch it back toward its original size, a little at a time, working the body and then the sleeves. Do not yank.
- Dry it flat, holding the new shape with a few heavy books or rustproof pins on a towel. Check and ease it again as it dries.
Be realistic. You may gain back some of the size, but not always all of it. If it still does not fit, pass it to someone smaller and learn from it.
How often should you wash a wool sweater?
Much less often than you think. Wool naturally resists odor and sheds a lot of everyday dirt. If you wear a shirt or tee underneath, a wool sweater can usually go five or more wears between washes, and many men wash theirs only a few times a season.
- Air it out between wears. Lay it over a chair back overnight. Most smells are gone by morning.
- Spot clean small marks with cool water and a drop of wool wash on a cloth.
- Brush it. A soft clothes brush lifts dust and lint from the surface.
- Wash it when it is visibly dirty, stained, or still smells after airing, and always before you put it away for the summer. Moths go for dirty wool first. Our guide on how to store wool clothes covers the off-season.
Washing less also means less pilling, less wear at the elbows, and a sweater that lasts years longer. If your sweater has started to pill, read how to get pills off a wool sweater.
Our wool sweaters and what they are made of
We keep our sweaters simple: midweight, a waffle knit, ribbed waist and cuffs, and a fleck in the yarn that hides the odd mark between washes. Both styles are wool blends, and that is on purpose. The wool brings the warmth and its natural resistance to odor. The blend adds durability, helps the sweater hold its shape, keeps the weight and the price down, and is often softer and less scratchy against the skin. It also makes the sweater more forgiving in the wash than a pure wool knit, though not immune: heat and a hard tumble can still shrink it. Treat them with the same cool-and-still method above, and check the care label in yours. Not sure which neckline suits you? Read crewneck vs. quarter button vs. quarter zip.
Crewneck Wool Sweater | Charcoal Gray Fleck
A midweight waffle-knit crewneck in a wool blend with a flecked yarn. It goes over a collared shirt for the office or under a jacket for a cold walk.
$69.95
Shop the Crewneck
Crewneck Wool Sweater | Sea Fleck
The same crewneck in a blue-green fleck. It also comes in Wood Fleck and Sunset Fleck, both $69.95.
$69.95
Shop Sea Fleck
Quarter Button Wool Sweater | Charcoal Gray Fleck
The same midweight waffle knit with a quarter-button placket, wood buttons, and corduroy trim. Wear it over an Oxford for dinner or over a tee on a Saturday.
$78.95
Shop the Quarter Button
Quarter Button Wool Sweater | Pine Fleck
The quarter button in a deep green fleck. Also available in Navy Fleck at the same price.
$54.95
Shop Pine FleckA wool shirt that is easier to live with
If you want wool warmth with less fuss, look at a wool-blend shirt. The Gunnison is a solid flannel in a pre-shrunk wool blend, and it wears like a shirt rather than a knit. Still wash it cold and skip high heat, and follow the care label. For plaid cotton shirts, see how to wash flannel.
Gunnison Wool-Blend Solid Flannel Shirt | Brown
A pre-shrunk wool-blend flannel with a soft cotton interior lining, engraved wooden buttons, and a flap chest pocket. Also in Dark Heather Charcoal.
$139.95
Shop the GunnisonFrequently asked questions
Can you put a wool sweater in the washing machine?
Yes, if the care label allows it. Use the wool, hand wash, or delicate cycle, cold water, the lowest spin, and a wool-safe detergent. Turn the sweater inside out and put it in a mesh bag. If the label says hand wash or dry clean only, follow the label.
What temperature should I wash a wool sweater in?
Cold or lukewarm, never warm or hot. Keep the wash and rinse water the same temperature, because a sudden change can shock the fibers. If the water feels warm on your wrist, it is too warm for wool.
Why did my wool sweater shrink?
Heat and agitation together. Warm water lifts the tiny scales on each wool fiber, and rubbing or tumbling locks them together so the fabric pulls tight. This is called felting. A hot wash, a hard spin, or a tumble dryer is usually the cause.
Does cold water shrink wool?
Cold water on its own rarely shrinks wool. Shrinking comes from heat combined with rubbing. Wool can still felt in cold water if it is agitated hard, which is why a gentle cycle and low spin matter.
What detergent is safe for wool?
A detergent labeled for wool or delicates. Avoid regular detergents with enzymes such as protease, which are made to break down protein and can weaken wool over time. Never use bleach on wool.
Can you put a wool sweater in the dryer?
No. The heat and tumbling of a dryer is the fastest way to shrink and felt wool, even on a low setting. Press the water out in a towel and dry the sweater flat.
How do you dry a wool sweater without stretching it?
Lay it flat on a dry towel or a mesh drying rack, reshape the body, cuffs, and hem while it is damp, and let it air dry out of direct sun and heat. Do not hang a wet sweater, because the weight of the water stretches it.
Can you unshrink a wool sweater?
Sometimes, partly. Soaking it in lukewarm water with hair conditioner or baby shampoo may help relax the fibers so you can gently stretch it back toward size, then dry it flat and pinned in shape. It works best on mild shrinking. A fully felted sweater usually will not recover.
How often should you wash a wool sweater?
Not often. Wool resists odor, so with a shirt underneath most sweaters can go five or more wears between washes. Air it out between wears, spot clean small marks, and wash it when it is dirty or still smells after airing, and before storing it for the season.
Are Buffalo Jackson wool sweaters 100% wool?
No. Our Crewneck and Quarter Button sweaters are wool blends. The wool brings warmth and natural odor resistance, and the blend adds durability, helps the sweater hold its shape, and is often softer against the skin. Blends are generally more forgiving in the wash, but still wash cold, skip the dryer, and follow the care label in yours.
Should I wash a wool sweater inside out?
Yes. Turning it inside out protects the outer face from rubbing, which helps prevent both pilling and fuzzing. Button any placket before washing too.
Xan Hood founded Buffalo Jackson Trading Co. in 2009. He designs our leather goods, flannels, wool, and outerwear in Matthews, North Carolina.