Why Does My Yarn Smell?

The six smells

Wool, and why it smells of sheep when it is wet

Raw wool arrives on the fiber carrying two things that are not wool. Lanolin is the waxy grease sheep secrete to waterproof their fleece. Suint is dried sheep sweat, mostly potassium salts. Scouring removes most of both before the wool is spun, but 'most' is not 'all', and what remains is what you can smell.

Water is what releases it. Dry wool holds the smell in; wet wool gives it up, which is why a wool sweater that is fine in the wardrobe announces itself in the rain. Damp also lets skin bacteria work on the residues, and the breakdown products are the sharper end of the smell.

What to do about each one

1. Air it first, for three days. Skein out of the bag, somewhere with moving air and out of sun. This alone fixes vinegar, most chemical smells and most musty smells, and it costs nothing.
2. Then wash the skein, not the garment. Re-skein the yarn into a loose hank, tie it in three or four places with waste yarn so it cannot tangle, and soak it in cool water with a wool wash for twenty minutes. Squeeze, do not wring, and dry flat.
3. For stubborn wool smell, add a splash of white vinegar to the soak and then rinse. It neutralises alkaline residues. Do not use it on a hand-dyed yarn that already smells of vinegar - that is a different problem.
4. Never use hot water or agitation on untreated wool. You will felt the skein and then you own a solid lump. Does wool yarn shrink explains why.
5. For mildew, stop. Mildew means the fiber has been colonised and the smell is the organism. It does not reliably wash out, it spreads to the rest of your stash, and it can provoke a reaction in anyone sensitive. Bin it or return it.

The vinegar smell on hand-dyed yarn

Hand-dyers use acid dyes on protein fibers, and the acid that fixes the dye is usually citric acid or plain white vinegar. A skein that has been dried without a long final rinse keeps some of it.

It is harmless and temporary. Air the skein; if you are impatient, soak it in cool water with a little wool wash and dry it flat. If the dye runs significantly during that soak, that is a separate issue - see does superwash wool bleed and how yarn is dyed and dye lots.

Synthetic smells

A new acrylic skein sometimes carries a faint sharp smell from manufacture - spinning oils, finishing agents, the packaging it traveled in. It should be gone within a week of airing and certainly after a wash.

What is not normal is a strong solvent smell that persists after airing and washing. That is worth a return. Acrylic yarn allergies and sensitivity covers the related question of skin reactions, which are far more often a response to finishing chemistry than to the polymer itself.

Keeping it from happening

• Never store yarn in sealed plastic. It traps the moisture already in the fiber and that is how musty and mildew both start. Breathable containers, see best yarn storage solutions.
• Do not store it anywhere that gets damp - a basement, a garage, under a sink.
• Wash and fully dry a finished wool item before putting it away for the season. Body oils left in the fiber are what the smell feeds on, and they attract moths.
• Air a thrifted or destashed skein before it goes near the rest of your stash. Smoke and mildew both travel.
• Do not try to mask it. Scented sachets and dryer sheets put a second smell on top of the first and leave residue in the fiber.