Wool Care: The Rules Nobody Tells You
Almost everyone has a wool story. The jumper that came out of the wash the size of a doll's cardigan. The blanket that turned into felt. The expensive cashmere that mysteriously thinned in one season. Most people blame heat, but heat is only part of the story — and not even the biggest part. After getting this wrong with three different jumpers, I went deep on the science and found that the rules people repeat are often wrong about why wool shrinks.
It's Agitation, Not Heat
Here's the thing nobody tells you: heat alone doesn't shrink wool. Pour boiling water over a wool fibre and not much happens. What shrinks wool — what actually causes the permanent, doll-sized disaster — is mechanical agitation, especially in the presence of water and an alkaline detergent. The fibres have tiny scales (like fish scales) that interlock when they rub against each other in water. Once interlocked, they're physically locked together; no amount of stretching gets them apart. This process is called felting, and it's irreversible. Heat makes it worse because it relaxes the fibre and makes scales easier to interlock. But the trigger is movement.
Why Your Washing Machine Is the Real Enemy
A 'wool cycle' on a normal washing machine still agitates the fabric. It's gentler than a normal cycle, but it's not zero motion. For genuinely valuable wool — anything you'd be sad to lose — hand wash in a sink or basin. The technique: cool water, a small amount of wool-specific detergent (Eucalan, Woolite, or any soap labelled for wool), and submerge-and-press for two minutes. No squeezing, no wringing, no agitating. Lift out, support the weight (wet wool is heavy — hold from underneath, never by the shoulders), and rinse in clean cool water with the same submerge-and-press motion.
The Drying Stage People Get Wrong
Most wool damage actually happens during drying, not washing. Never hang wool — it stretches under its own weight and the shape never returns. Never tumble dry — even the lowest heat setting moves the fibres around enough to felt. The correct method: roll the wet jumper in a clean dry towel and press gently to extract water (this replaces wringing without the damage), then lay flat on a fresh dry towel on a flat surface. Reshape to its original dimensions while wet. Leave for 24–48 hours. Patience here is the difference between a jumper that looks like it always did and one that doesn't fit right anymore.
On Stains
Liquid spills
Blot immediately with a clean cloth. Don't rub — same felting principle. For coloured spills (wine, coffee), dab with cold water working from the outside inward. For protein stains (blood, milk), use cold water only — warm water cooks the protein into the wool and you'll have a permanent stain.
Oil-based stains
Treat with a wool-safe degreaser, not dish soap. Most household dish soaps are too alkaline for wool and will damage the fibres. A small amount of plain shampoo (the kind formulated for hair, which is also a protein fibre) is a safer alternative.
Sweat and body odour
Wool actually resists body odour better than synthetic fabrics — that's part of why merino base layers are so popular. If a wool item smells, often the fix is simply hanging it in fresh air for 24 hours. Wool's natural antimicrobial properties handle most of it without any cleaning at all.
The Storage Trap
Wool's other enemy is moths, and the most common reason people lose stored wool is putting it away dirty. Body oils and food traces attract clothes moths, who lay eggs in your favourite cardigan. Always wash wool before long-term storage. Store with cedar blocks or lavender (which actually deter moths, unlike most internet remedies) rather than mothballs (which work but smell terrible and contain chemicals you don't want on your skin).
What to Do If You've Already Felted Something
Honestly? Most felted wool is permanently felted. The internet will tell you about hair conditioner soaks and gentle stretching to 'rescue' a shrunk jumper — these methods work occasionally on mild cases but rarely restore the original size and shape. If a beloved item has felted badly, the most realistic options are: cut it down into a smaller garment, repurpose as fabric (felted wool makes excellent slipper soles and small bags), or accept the loss and learn the rule for next time. The honest truth is that prevention is the only reliable strategy.