You brought home a beautiful fleece from a fiber festival, tucked it into a corner of the studio, and told yourself you'd get to it soon. Six months later, you open the bag and find the locks compressed into a flat mat, a faint musty smell, and — if you're unlucky — the telltale signs of moth damage. It's a frustrating experience, and an entirely avoidable one. Raw fleece is more resilient than most people expect, but it does have specific storage needs that, if ignored, can quietly ruin months of fiber quality.
Raw fleece is a natural material that can change over time if stored improperly. Dirt, moisture, insects, and compression can all affect the quality of wool before it is prepared for spinning on a Turkish drop spindle. Proper fleece storage helps preserve staple strength, fiber alignment, and overall fleece condition until the fiber is ready to be washed, combed, or otherwise processed.
Keep Fleece Dry and Away From Sunlight
Moisture is the biggest threat to stored wool. Damp conditions create the environment that mold and mildew need to grow, and once mold takes hold in a fleece, the fiber deteriorates quickly and the damage cannot be reversed. The key is to store fleece in a genuinely dry location — not just a location that feels dry, but one with consistently low humidity and good airflow. Basements and garages are often problematic because they experience humidity fluctuations, especially in summer. A climate-controlled interior room is a much better choice.
UV light from direct sunlight is the second major environmental threat. Ultraviolet light breaks down the protein structure of wool fibers over time, causing them to become brittle, weakened, and faded. The damage is cumulative and irreversible — once the fiber has been weakened by UV exposure, it cannot be restored. Storing fleece in a dark location, inside covered containers, and away from windows with direct sunlight is the most effective way to prevent UV damage during long-term storage. Even indirect light through a window over many months can cause noticeable fading in colored fleece.
Use Breathable Containers and Avoid Compression
Sealed plastic bags are one of the most common storage mistakes. They trap moisture and prevent the airflow that wool needs to stay in good condition. If any moisture is present in the fleece when it goes into a sealed bag — even a small amount — it cannot escape, and the resulting damp environment can lead to mold or mildew growth that damages the fiber. Breathable containers such as paper bags, cardboard boxes, pillowcases, or fabric bags are much better choices because they allow air to circulate while still protecting the fleece from dust and debris. If plastic containers are the only option, leaving the lid slightly ajar or using containers with ventilation holes provides enough airflow to prevent moisture buildup.
| Storage Method | Effect on Fiber | Recommended? |
|---|---|---|
| Paper bags or cardboard boxes | Allows airflow; preserves lock structure | Yes — best for most situations |
| Fabric bags or pillowcases | Breathable; protects from dust | Yes — good for medium-term storage |
| Sealed plastic bags | Traps moisture; risks mold | No — avoid for long-term storage |
| Tightly packed containers | Compresses fiber; flattens crimp and locks | No — always store loosely |
Compression is a separate but related problem. Wool fiber has a natural three-dimensional structure — the crimp, the lock formation, and the overall loft of the fleece — that makes it easier to open, sort, and prepare for spinning. When fleece is packed tightly into a compressed space for an extended period, the weight and pressure gradually flatten this structure. The locks lose their definition, the crimp is partially compressed, and the fiber becomes more difficult to tease apart and open before preparation. Always store fleece loosely, in a container that allows the fiber to sit without being pressed down.
Protect Against Moths and Other Insects
Moth larvae are the primary insect threat to stored wool. The adult moths do not eat fiber, but they lay eggs in the fleece and the larvae feed on the protein in the wool as they develop. The most obvious signs of moth damage are small holes or bare patches where the fiber has been eaten away, powdery frass (the waste left by moth larvae), small white larvae, or silky webbing in the fleece. Fiber in damaged areas will break very easily when pulled. If you find any of these signs, isolate the affected fleece immediately to prevent the infestation from spreading to other stored fiber.
The most effective protection is a combination of cleanliness, regular inspection, and physical barriers. Keeping the storage area clean and free of food debris reduces the attractiveness of the space to moths. Inspecting stored fleece every few months allows early detection of any infestation before it spreads. Cedar blocks, lavender sachets, and other natural moth deterrents can help discourage moths from laying eggs near the fleece, though they are not a complete solution on their own. For long-term storage of valuable fleece, sealed containers with cedar or lavender inside provide the most reliable protection. If you discover an infestation, freezing the fleece for at least two weeks at 0°F (-18°C) kills all life stages of moth, including eggs and larvae.
Store Raw vs Washed Fleece
Most spinners store raw fleece unwashed, and this is generally the recommended approach for long-term storage. The natural lanolin in raw fleece provides some protection against pests and environmental damage, and unwashed fleece is more stable in storage than washed fleece. Washed fleece has had its natural oils removed and is more vulnerable to moth damage because the protein structure of the fiber is more accessible to larvae without the lanolin coating. Washed fleece also needs to be completely dry before storage — any residual moisture can cause mold or mildew.
If you do choose to wash before storing, ensure the fleece is thoroughly dry — not just surface-dry, but dry all the way through — before placing it in storage. Store washed fleece in breathable containers with moth protection, and check it more frequently than you would raw fleece. For most situations, washing just before processing rather than before storage gives the best results and reduces the risk of storage-related damage. Learn more about how to prepare raw wool before using wool combs or hackles.
Organize and Label Your Fleece
Labeling is not strictly necessary, but it becomes increasingly valuable as a fiber collection grows. Without labels, it can be very difficult to remember the breed, staple length, or source of a fleece after it has been in storage for several months. A simple label attached to the storage container — noting the breed, the date it was shorn or purchased, the staple length, any notes about fiber quality, and any planned preparation method — takes only a moment to create and can save significant time and frustration later. For spinners who work with multiple breeds or buy fleece at fiber festivals, labeling is essentially essential for keeping track of what is in the collection and matching the right fiber to the right project.
| Sorting Method | Benefit |
|---|---|
| Breed separation | Predictable fiber characteristics; easier project matching |
| Staple length grouping | Easier preparation planning; know which tool to use |
| Quality grading | Better project selection; prioritize best fiber for best projects |
| Date labeling | Track age of stored fiber; process oldest first |
Organized storage also means processing older fleece before newer acquisitions — a first-in, first-out approach that prevents any single fleece from sitting in storage so long that it deteriorates. Learn more about how to read a raw fleece like a spinner and how to identify high quality wool for spinning.
Check Stored Fleece Before Processing
Even well-stored fleece should be checked before processing, especially if it has been in storage for more than a year. Perform the snap test on several locks from different areas of the fleece to confirm that the staple strength has been maintained. Check for any signs of moth damage — holes, frass, webbing, or larvae. Open a few locks and look for any signs of mold or mildew, which may appear as discoloration or a musty smell. Check the tips for any weathering or brittleness that may have developed during storage.
Raw fleece stored correctly — dry, dark, loosely packed, in breathable containers, with moth protection — can remain in excellent condition for several years. The lanolin in unwashed raw fleece provides natural protection, and a cool, stable environment does the rest. A quick inspection before processing confirms that the storage conditions have done their job and that the fiber is ready to wash, comb, and spin. Learn more about understanding staple strength in wool fiber.
Key Takeaways
- Raw fleece stored correctly can remain in excellent condition for several years — the key factors are dryness, darkness, pest protection, and minimal compression
- Moisture is the biggest storage threat — damp conditions cause mold and fiber deterioration; always store in dry locations with good airflow
- Sealed plastic bags trap moisture and should be avoided for long-term storage — use paper bags, cardboard boxes, or fabric bags instead
- Compression flattens lock structure and crimp over time, making the fleece harder to open and prepare — always store loosely
- UV light from direct sunlight breaks down wool protein irreversibly — store fleece in dark, covered locations away from windows
- Moth larvae are the primary pest threat — inspect stored fleece every few months and use cedar or lavender in sealed containers for valuable fiber
- Infested fleece can be treated by freezing at 0°F (-18°C) for at least two weeks, which kills all moth life stages including eggs and larvae
- Store raw fleece unwashed — natural lanolin provides protection against pests and environmental damage; wash just before processing for best results
- Label each fleece with breed, date shorn, staple length, and preparation notes — essential for managing a growing fiber collection
Frequently Asked Questions
How long can raw wool be stored?
Raw fleece stored correctly can remain in excellent condition for several years. The key factors are dryness, darkness, pest protection, and minimal compression. Fleece that is kept in a cool, dry location with good airflow, protected from moths and other insects, and stored loosely rather than packed tightly can hold its fiber quality for a very long time. The lanolin in unwashed raw fleece actually provides some natural protection against pests and environmental damage. Fleece that has been stored in poor conditions — damp, compressed, or exposed to insects — can deteriorate much more quickly, sometimes within a single season. When in doubt about the condition of stored fleece, performing a snap test on a few locks before processing is the best way to assess whether the fiber has retained its strength.
Should fleece be stored in plastic bags?
Sealed plastic bags are generally not recommended for long-term raw fleece storage because they trap moisture and prevent the airflow that wool needs to stay in good condition. If any moisture is present in the fleece when it goes into a sealed bag — even a small amount — it cannot escape, and the resulting damp environment can lead to mold or mildew growth that damages the fiber. Breathable containers such as paper bags, cardboard boxes, pillowcases, or fabric bags are much better choices because they allow air to circulate while still protecting the fleece from dust and debris. If plastic containers are the only option, leaving the lid slightly ajar or using containers with ventilation holes provides enough airflow to prevent moisture buildup.
Can sunlight damage wool?
Yes, and the damage can be significant with prolonged exposure. Ultraviolet light breaks down the protein structure of wool fibers over time, causing them to become brittle, weakened, and faded. The tips of the locks — which are the oldest part of the fiber and have been exposed to the elements the longest — are most vulnerable to UV damage, but extended storage near a sunny window can affect the entire fleece. The damage is cumulative and irreversible: once the fiber has been weakened by UV exposure, it cannot be restored. Storing fleece in a dark location, inside covered containers, and away from windows with direct sunlight is the most effective way to prevent UV damage during long-term storage.
Do I need to label fleece?
Labeling is not strictly necessary, but it becomes increasingly valuable as a fiber collection grows. Without labels, it can be very difficult to remember the breed, staple length, or source of a fleece after it has been in storage for several months. A simple label attached to the storage container — noting the breed, the date it was shorn or purchased, the staple length, any notes about fiber quality, and any planned preparation method — takes only a moment to create and can save significant time and frustration later. For spinners who work with multiple breeds or buy fleece at fiber festivals, labeling is essentially essential for keeping track of what is in the collection and matching the right fiber to the right project.
How do you protect wool from insects?
Moth larvae are the primary insect threat to stored wool — the adult moths do not eat fiber, but they lay eggs in the fleece and the larvae feed on the protein in the wool as they develop. The most effective protection is a combination of cleanliness, regular inspection, and physical barriers. Keeping the storage area clean and free of food debris reduces the attractiveness of the space to moths. Inspecting stored fleece every few months allows early detection of any infestation before it spreads. Cedar blocks, lavender sachets, and other natural moth deterrents can help discourage moths from laying eggs near the fleece, though they are not a complete solution on their own. For long-term storage of valuable fleece, sealed containers with cedar or lavender inside provide the most reliable protection.
Why should you avoid compressing fleece?
Wool fiber has a natural three-dimensional structure — the crimp, the lock formation, and the overall loft of the fleece — that makes it easier to open, sort, and prepare for spinning. When fleece is packed tightly into a compressed space for an extended period, the weight and pressure gradually flatten this structure. The locks lose their definition, the crimp is partially compressed, and the fiber becomes more difficult to tease apart and open before preparation. In severe cases, compression can also encourage the fiber scales to interlock slightly, making the fleece harder to process without causing breakage. Storing fleece loosely — in a container that allows the fiber to sit without being pressed down — preserves the natural structure and makes preparation much easier when the time comes.
Should I wash fleece before storing it long-term?
Most spinners store raw fleece unwashed, and this is generally the recommended approach for long-term storage. The natural lanolin in raw fleece provides some protection against pests and environmental damage, and unwashed fleece is more stable in storage than washed fleece. Washed fleece, while cleaner, has had its natural oils removed and is more vulnerable to moth damage because the protein structure of the fiber is more accessible to larvae without the lanolin coating. Washed fleece also needs to be completely dry before storage — any residual moisture can cause mold or mildew. If you do choose to wash before storing, ensure the fleece is thoroughly dry, store it in breathable containers, and use moth protection. For most situations, washing just before processing rather than before storage gives the best results.
What are the signs that stored fleece has been damaged by moths?
The most obvious signs of moth damage in stored fleece are small holes or bare patches where the fiber has been eaten away, powdery residue (which is frass — the waste left by moth larvae), and the presence of small white larvae or silky webbing in the fleece. The fiber in damaged areas will feel weak and break very easily when pulled, because the larvae have consumed the protein structure of the wool. Adult clothes moths are small, golden-colored moths that tend to flutter weakly rather than flying strongly. If you find any of these signs, isolate the affected fleece immediately to prevent the infestation from spreading to other stored fiber. Freezing the fleece for at least two weeks at 0°F (-18°C) kills all life stages of moth, including eggs and larvae, and is the most reliable treatment for an infested fleece.
0 comments