The most common mishap in knitting doesn’t happen during knitting. It happens the first time you wash. A machine wash at 40°C, a bit too much spinning, a wrongly chosen program – and hours of work suddenly end up in a felted sweater that would fit a Barbie doll. To prevent this from happening to you, this article explains everything you need to know about proper wool care.

Why is wool sensitive?

Wool consists of protein fibers – the same basic structure as human hair. These fibers have a characteristic scale surface. The scales are the reason for many of wool’s positive properties: they provide natural elasticity and resilience, allow moisture to be absorbed and released, and give the yarn its pleasant hand feel.

The same scales are also the reason why wool shrinks and felts with improper care. When wool scales open in hot water and hook together due to mechanical movement (washing machine drum, vigorous rubbing), the result is irreversible. Felted wool cannot be undone – the process cannot be reversed.

This makes temperature and friction the two decisive factors in wool care.

Superwash vs. non-superwash: The most important difference

Before you know how to care for a wool piece, you need to know whether the yarn used is superwash-treated or not. That is the basic distinction.

Superwash wool: The yarn has undergone a chemical treatment where the scale structure of the fibers is either flattened or coated with a polymer. The result: The fibers can no longer easily hook together. Superwash yarns are machine washable – with the right program.

Non-superwash wool: The natural scale structure is fully preserved. This wool retains all its natural properties unchanged – but it felts more easily. Hand Wash is the safest method. With careful treatment, the delicate wool program of the machine is often possible – but the risk is higher.

How can you tell? Look at the yarn ball label. For Superwash, it is either written directly as "Superwash" or indicated by the washing symbol (a basin with a hand inside = Hand Wash; a basin without a hand = Machine Wash possible; sometimes with temperature indication and dots for intensity).

Examples from the BONIFAKTUR range:

Superwash (Machine Wash possible): Malabrigo Rios, Hedgehog Fibres Sock Yarn, CowGirlBlues Proper Sock

Not Superwash (Hand Wash recommended): KFO Merino, KFO Heavy Merino, KFO Cotton Merino, Rauma Finull, Sandnes Peer Gynt, Istex Léttlopi, Holst Supersoft, BC Garn Bio Balance GOTS

Hand Wash: How to do it right

The safe method for all wool pieces – superwash or not. Hand Wash is slower than the machine, but the gentlest way for high-quality knitted pieces.

Step 1: Prepare the water

Lukewarm water, about 30°C. Not hot – hot water opens the scale structure and increases the risk of felting. Not ice cold – extreme temperature changes (warm to cold) can damage wool just as much as too much heat. The temperature of the water when rinsing should be the same as when washing.

Step 2: Detergent

A mild wool wash or shampoo. There are special wool washes (like Eucalan or Soak) that require no rinsing – just soak and rinse cold. For high-quality wool, a true wool wash with Lanolin (re-fatting) is always the best choice. Hair shampoo can also work – but be careful: many modern shampoos contain conditioners, silicones, or proteins that coat the wool fiber and can make it flat or greasy. If shampoo, then a simple one without these additives.

What is not suitable: regular heavy-duty detergent or universal detergent. These are too harsh for protein fibers and can damage the wool structure. Enzyme-containing detergents (recognizable by the term “enzyme cleaner” or “bio-active”) actively break down proteins – and wool is a protein. Never use enzyme detergents on wool. By the way, silk reacts even more sensitively to conventional detergents than wool – for silk blends, a special wool wash is especially important.

Step 3: Soak, don’t rub

Fully immerse the wool piece in the water and gently press until it is completely soaked. Then let it soak for about 10–15 minutes. Do not rub, knead, or press. Friction is the enemy of wool.

The water will solve the dirt problem – you don’t need to help mechanically.

Step 4: Rinse

Drain the dirty water. Refill with new lukewarm water at the same temperature. Gently press the piece again and let the rinse water drain off. Repeat this step until the water is clear.

Important: Never use cold water for rinsing if the wash water was warm. This is the so-called shock-felting effect: The fiber scales raise in warmth – if cold water suddenly hits, they contract so quickly that they irreversibly hook together. The result is irreversible felting. Ideally, the temperature should remain constant at about 30°C – from washing to the last rinse.

Step 5: Press out, don’t wring

Do not wring the wool piece – twisting and rubbing damages the structure. Instead: gently press to squeeze out excess water. Then place the piece in a dry towel, roll it up, and press lightly. The towel absorbs most of the remaining moisture.

Step 6: Dry flat

Lay the damp wool piece flat on a surface (towel, blocking mat) and let it dry in shape. Never hang – damp wool pieces stretch under their own weight. A damp sweater hanging on a hanger will become wider and longer at the bottom and tighter at the top.

Avoid direct sunlight when drying: UV light can fade some fiber colors over time.

Machine Wash: When is it possible?

Only for Superwash yarns – and even then only with the right program.

Program: Wool program (the symbol on the washing machine is usually a ball of yarn or the text “Wool”). The wool program uses little mechanical movement, low temperatures (30–40°C), and low spin speeds.

Temperature: 30°C is safer than 40°C. Some Superwash yarns are approved for 40°C – check the label.

Spinning: Less spinning is better than more. 400–600 rpm is enough. At 1200 rpm, even Superwash wool can be damaged.

Detergent: Wool Wash or mild delicate detergent. No enzyme detergents.

Important note: Superwash does not automatically mean machine wash is safe. If the label does not clearly state this or if the piece is valuable, it’s better to wash by hand.

Warning – Superwash and “Waxing": Superwash-treated wool has a special property that surprises many. Because the scale structure is flattened or coated, the fibers lose their natural grip when wet. This means: A wet Superwash sweater can stretch extremely and suddenly look twice as large as before. This is not felting, but the opposite – the fibers slide apart unchecked. That’s why flat drying (steps 5 and 6) is especially important for Superwash: The piece must be actively pushed back to its original dimensions when laid on a towel.

Dryer: Almost always no

Almost no wool item should go in the dryer. The combination of heat and mechanical movement in the drum is the most effective way to ruin a knitted wool piece.

Exceptions: Some modern Superwash yarns (e.g., certain Merino blends) are not only approved for the tumble dryer – they actually need it. A short cycle on gentle setting helps the fibers "spring back" and regain their shape. This is directly related to stretching out: Without scale grip, fibers slip apart when wet, and the controlled heat of the dryer brings them back. If the label shows the tumble dryer symbol, it often indicates the yarn tends to stretch out otherwise. When in doubt: drying flat and actively shaping remains the gold standard.

Blocking: The Final and Most Important Step

After washing – and after complete drying – Wool can be wonderfully shaped and permanently set. This process is called blocking.

For Shawls and Stolas: Stretch the damp piece on a blocking mat or foam surface. Blocking pins (straight or T-pins) hold the edges in the desired shape. Lace patterns fully open only after blocking: openings widen, edges straighten, and the piece takes its final size.

For Sweaters and Cardigans: Lay the damp item flat on a surface, shape it (straight shoulder seams, even sleeves, straight hem), and let dry. The result is a noticeably more professional-looking piece.

For Socks: Sock blockers are available as wooden or plastic forms. Pull the damp pair of socks over the form, shape them, and let dry. The socks keep their shape better afterward.

Storage: Properly Storing Wool Items

Store Flat: Wool items should not be hung on hangers. Heavy Wool sweaters stretch out over time on hangers – shoulder seams stretch, sleeves lengthen, the sweater loses its shape. Folded flat and stacked on a shelf: that’s correct.

Preventing Moth Infestation: Moths eat protein fibers – that means Wool, Cashmere, Alpaca, and Silk. Lavender sachets, cedarwood pieces (cedarwood hangers or cedarwood balls), or moth repellents without naphthalene protect storage. Air regularly.

Long-term Storage: Wool items stored for more than one season should be freshly washed beforehand. Dirt or sweat residues attract moths.

Brief Summary: Right or wrong?

Right: Lukewarm water, mild Wool Wash, soaking without rubbing, rinse with water of the same temperature, gently squeeze, dry flat, blocking.

Wrong: Hot water, regular detergent, vigorous rubbing or wringing, switching between very warm and very cold water, tumble drying, hanging to dry.

Read More: