The first time you wash a raw fleece, it can feel like a high-stakes experiment. You've got a beautiful bag of fiber, a sink full of hot water, and a nagging worry that one wrong move is going to turn the whole thing into a felted mat. That worry is understandable — wool can felt during washing — but the rules that prevent it are simple, and once you understand them, scouring fleece becomes one of the most satisfying steps in the whole process.
After a fleece has been skirted and sorted, the next step in fiber preparation is washing the wool. Washing raw fleece removes dirt, sweat salts, and much of the natural lanolin that coats the fibers. Proper scouring helps create cleaner fiber that is easier to prepare with tools such as wool combs or hackles and easier to spin into yarn on a Turkish drop spindle. Learn more about grease wool vs washed wool.
Why Raw Wool Needs Washing and What You'll Need
Raw fleece contains a variety of natural and environmental materials that accumulate while the sheep grows the fleece. Lanolin is the most significant — it's a natural grease produced by the sheep's skin that protects the fleece from moisture and weather. While lanolin gives raw fleece its characteristic feel and cohesion, too much of it makes the fiber sticky and difficult to process. High-lanolin breeds like Merino can have fleeces that are 30–50% lanolin by weight, which means the washed fleece can be significantly lighter than the raw fleece. Dirt, dust, sweat salts, and vegetable matter round out the list of what needs to come out.
| Lanolin Level | Effect on Fiber | Washing Needed? |
|---|---|---|
| High lanolin | Sticky and difficult to process | Yes — multiple wash cycles |
| Moderate lanolin | Slight cohesion; manageable | Yes — one or two wash cycles |
| Low lanolin | Clean and open; easy to process | Yes — one wash cycle usually sufficient |
For supplies, you need large tubs or basins (a utility sink, a large stockpot, or plastic storage totes all work), hot water, a wool-safe enzyme-free detergent, and mesh drying racks or screens. The most important characteristic of the detergent is that it must be enzyme-free — enzymes are added to many laundry detergents to break down protein stains, and wool is a protein fiber that enzymes will damage. Purpose-made wool washing products such as Unicorn Fibre Wash or Kookaburra Wool Wash are formulated specifically for this purpose. Plain dish soap — particularly grease-cutting formulas like Dawn — is a widely used and effective alternative. Learn more about how to prepare raw wool before using wool combs or hackles.
Water Temperature: The Most Important Variable
Water temperature is the single most important variable in washing wool successfully. Lanolin is a grease, and like all greases, it requires heat to liquefy and release from the fiber. Cold or lukewarm water will not dissolve lanolin effectively, no matter how long the fleece soaks or how much detergent is used. Most spinners use water that is comfortably hot to the touch — roughly 140–160°F (60–70°C) — for the wash cycle. At this temperature, the lanolin liquefies and releases from the fiber into the wash water, where the detergent holds it in suspension so it can be drained away.
The critical rule is consistency: the rinse water must be the same temperature as the wash water. Moving fleece from hot wash water directly into cold rinse water is one of the most reliable ways to cause felting. The sudden temperature change causes the microscopic scales on the surface of the wool fibers to contract and interlock, which is the mechanism of felting. If the wash water has cooled significantly by the time the fleece needs to be rinsed, allow the rinse water to cool to match before transferring the fleece, or warm the rinse water to match the current wash water temperature. Never add cold water to a basin containing hot wet fleece.
Washing the Fleece: Soak, Don't Agitate
Fill the basin with hot water and add a small amount of detergent — a tablespoon or two is usually sufficient for a small basin; more for a larger load. Dissolve the detergent in the water before adding the fleece. Gently lower the fleece into the water, pressing it down lightly to submerge it, and then leave it alone. The fleece should soak for 20–30 minutes, during which the hot water and detergent work to dissolve and lift the lanolin and dirt from the fiber. Do not stir, poke, swirl, or otherwise agitate the fleece during this time — agitation combined with heat and moisture is what causes felting.
After soaking, carefully lift the fleece out of the water or drain the basin while leaving the fleece as undisturbed as possible. Support the weight of the wet fleece from underneath rather than lifting it by one end, which can stretch and tangle the locks. Gently press the fleece against the side of the basin to remove excess water — do not wring or squeeze. Repeat the wash cycle if the fleece is heavily lanolinated — the wash water from the first cycle of a Merino fleece will often turn dark brown or yellow, and a second wash in fresh hot water and detergent will remove significantly more lanolin.
Rinsing and Preventing Felting
Rinsing removes the detergent and the lanolin it has captured from the fiber. Fill the rinse basin with water at the same temperature as the wash water, then gently transfer the fleece and allow it to soak for 10–15 minutes. Do not agitate. Lift the fleece out, press gently to remove excess water, and check the rinse water — when it runs clear with no soapy feel or smell, the fleece is adequately rinsed. A heavily lanolinated fleece may need two or three rinse cycles. Leaving detergent residue in the fiber can make it feel stiff or sticky after drying and can interfere with preparation and spinning.
Felting is the primary risk during washing, and it is caused by the combination of heat, moisture, and mechanical agitation. The rules that prevent it are simple: never stir, rub, or squeeze the fleece while it is wet and warm; keep the water temperature consistent between wash and rinse; and handle the fleece as little and as gently as possible throughout the process. A fleece that has been felted during washing cannot be unfelted — the fiber scales that have interlocked are permanently entangled. Following these rules consistently makes felting during washing essentially avoidable.
Drying the Wool
After the final rinse, the goal is to remove moisture as quickly as possible without agitating the fiber. Gently press the fleece against the side of the basin to remove excess water — do not wring or squeeze. Placing the fleece in a mesh laundry bag and giving it a brief spin in a washing machine on the spin-only cycle is an efficient way to remove most of the water without agitation — the spin cycle does not agitate the fiber the way a wash cycle does, and it dramatically speeds up drying time.
Spread the fleece in thin, even layers on a mesh drying rack or window screen where air can circulate freely around and through the fiber. Avoid piling the fleece in thick layers, which traps moisture and slows drying — and in humid conditions, thick piles can develop mold before the center of the pile dries. In warm, dry weather, fleece can dry outdoors in a few hours; in humid or cool conditions, it may take a full day or longer. The fleece must be completely dry — not just surface-dry, but dry all the way through — before storage or preparation to prevent mold.
What Comes After Washing
Once the wool is completely dry, the fiber is ready for the next stage of preparation. Clean, dry fiber is significantly easier to work with than raw fleece — the locks open more readily, the fiber moves through combs and hackles more smoothly, and the preparation tools stay cleaner longer. The first step after washing is usually opening the fiber locks, which loosens the compressed lock structure and makes the fiber easier to load onto combs or hackles. From there, the fiber can be combed or hackled into smooth, aligned top for worsted spinning, or blended with other fibers for custom preparations.
The fleece does not need to be stripped of all lanolin to be ready for preparation — some spinners prefer to leave a small amount in the fiber for a slightly cohesive feel during combing and spinning, which is a matter of personal preference. What matters is that the fiber feels light and open rather than heavy or sticky, and that individual locks separate easily without clumping. A well-scoured fleece that has been dried properly is one of the most satisfying materials to work with — clean, light, and ready to become yarn. Learn more about creating custom fiber blends with a wool hackle.
Key Takeaways
- Scouring removes lanolin, dirt, sweat salts, and vegetable matter from raw fleece so it can be combed, hackled, and spun more effectively
- Use hot water (140–160°F / 60–70°C) to dissolve lanolin — lanolin is a grease that requires heat to liquefy and release from the fiber
- The most important felting rule is temperature consistency — rinse water must match wash water temperature; sudden changes cause the fiber scales to lock permanently
- Never stir, rub, or squeeze the fleece while it is wet and warm — agitation combined with heat and moisture is what causes irreversible felting
- Use an enzyme-free detergent — enzymes in standard laundry detergents break down protein fibers and will damage wool
- Rinse until the water runs clear with no soapy feel or smell — detergent residue left in the fiber makes it stiff and interferes with preparation
- After the final rinse, press gently against the basin to remove excess water — a spin-only washing machine cycle is an efficient way to remove most moisture without agitation
- Spread washed fleece in thin layers on a mesh rack with good airflow — thick piles trap moisture and can cause mold before the fiber dries
- The fleece does not need to be stripped of all lanolin — some spinners prefer to leave a small amount for a slightly cohesive feel during preparation
Frequently Asked Questions
What does scouring wool mean?
Scouring is the traditional term for washing raw fleece to remove the lanolin, dirt, sweat salts, and vegetable matter that accumulate in the fiber while it is on the sheep. The word comes from the vigorous washing methods used historically, though modern hand scouring is much gentler to preserve the fiber. The goal of scouring is not necessarily to remove every trace of lanolin — some spinners prefer to leave a small amount in the fiber for a slightly cohesive feel — but to remove enough that the fiber can be opened, combed, hackled, and spun without the grease interfering with the process. A well-scoured fleece feels clean and light rather than sticky or heavy, and the individual locks open easily without clumping together.
Can wool felt during washing?
Yes, and felting during washing is one of the most common mistakes beginners make with raw fleece. Felting happens when the microscopic scales on the surface of wool fibers interlock and become permanently entangled, which is triggered by the combination of heat, moisture, and mechanical agitation. In a washing context, this means that stirring, rubbing, squeezing, or agitating the fleece while it is wet and warm can cause irreversible felting. The other major cause of felting during washing is a sudden change in water temperature — moving the fleece from hot wash water directly into cold rinse water causes the fiber to shock and the scales to lock together. Preventing felting requires keeping the water temperature consistent throughout the wash and rinse process and handling the fleece as little and as gently as possible.
How many times should fleece be rinsed?
The number of rinses needed depends on how much lanolin and dirt the fleece contained and how much detergent was used. A heavily lanolinated fleece from a breed like Merino may need three or four wash cycles followed by two or three rinses to get fully clean. A cleaner fleece with less lanolin may be adequately clean after one or two washes and a single rinse. The best way to judge whether the fleece is rinsed enough is to check the rinse water — when it runs clear and no longer has a soapy feel or smell, the fleece is ready to dry. Leaving detergent residue in the fiber can make it feel stiff or sticky after drying and can interfere with preparation and spinning.
Do all fleeces need washing?
Most raw fleeces benefit from washing before preparation and spinning, but it is not an absolute requirement. Some spinners choose to spin in the grease — spinning the raw, unwashed fleece with its lanolin intact — which is a traditional technique that produces a cohesive, slightly waxy yarn that is then washed after spinning. Spinning in the grease works best with fleeces that have moderate lanolin levels and minimal vegetable matter contamination. Very heavily lanolinated fleeces are difficult to spin without washing because the grease makes the fiber sticky and resistant to drafting. For most spinners, particularly those using fiber preparation tools like combs or hackles, washing before preparation produces significantly better results and makes the tools much easier to use and clean.
What temperature water should you use for washing wool?
The water should be hot enough to dissolve the lanolin — lanolin is a grease that requires heat to liquefy and release from the fiber — but not so hot that it risks burning the fiber or shocking it when transferred to cooler rinse water. Most spinners use water that is comfortably hot to the touch, roughly 140–160°F (60–70°C), for the wash cycle. The critical rule is consistency: the rinse water should be the same temperature as the wash water. Moving fleece from hot wash water into cold rinse water is one of the most reliable ways to cause felting. If the wash water has cooled significantly by the time the fleece needs to be rinsed, allow the rinse water to cool to match before transferring the fleece, or warm the rinse water to match the current wash water temperature.
How do you dry wool after washing?
The goal when drying washed fleece is to remove moisture as quickly as possible without agitating the fiber. After the final rinse, gently press the fleece against the side of the basin to remove excess water — do not wring or squeeze. Placing the fleece in a mesh laundry bag and giving it a brief spin in a washing machine on the spin-only cycle is an efficient way to remove most of the water without agitation. Spread the fleece in thin, even layers on a mesh drying rack or window screen where air can circulate freely around and through the fiber. Avoid piling the fleece in thick layers, which traps moisture and slows drying. In warm, dry weather, fleece can dry outdoors in a few hours; in humid or cool conditions, it may take a full day or longer. The fleece must be completely dry before storage or preparation to prevent mold.
What detergent should I use to wash wool?
The most important characteristic of a wool washing detergent is that it should be free of enzymes, which are added to many laundry detergents to break down protein stains — and wool is a protein fiber that enzymes will damage. Beyond that, a good wool washing detergent should cut through lanolin effectively, rinse out cleanly without leaving residue, and be gentle enough not to strip the fiber of all its natural oils. Purpose-made wool washing products such as Unicorn Fibre Wash, Kookaburra Wool Wash, and similar products are popular among spinners because they are formulated specifically for this purpose. Plain dish soap — particularly Dawn or similar grease-cutting formulas — is a widely used and effective alternative that cuts lanolin well and rinses cleanly. Avoid fabric softeners, which coat the fiber and can interfere with preparation and spinning.
How do I know when the wool is clean enough after washing?
The cleanliness of washed fleece can be assessed by several simple checks. The wash water should run noticeably cleaner with each successive wash cycle — the first wash of a heavily lanolinated fleece will often turn dark brown or yellow, while subsequent washes should be progressively lighter. The rinse water should run clear with no soapy feel or smell before the fleece is considered clean. The fiber itself should feel light and open rather than heavy or sticky, and individual locks should separate easily without clumping. If the fiber still feels greasy or tacky when dry, it likely needs another wash cycle. Some spinners prefer to leave a small amount of lanolin in the fiber for a slightly cohesive feel, which is a matter of personal preference — the fiber does not need to be completely stripped of all oils to be ready for preparation.
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