Wool

Wool is a protein fiber, grown rather than picked. It’s made of keratin, the same family of proteins as hair and nails, shorn from sheep and sorted by grade before spinning. That sorting matters, because one word on a label covers fibers that can behave like two different materials.

Grade is measured in microns, the average diameter of the fiber. Fine merino sits at the thin end of the range, while the coarser wools bred for carpets and outerwear can be several times thicker. It’s the same protein, but it makes a very different fabric against your neck.

How does wool handle moisture?

Better than almost any other common fiber, and it starts with crimp. Wool fibers have a natural wave that holds air between them, and trapped air is what insulation really is. That’s why wool can keep you warm without much weight, and why its loft recovers after a trip in a suitcase.

Wool is elastic, too. It bends and springs back, so it wrinkles less than many fabrics and hangs with weight rather than stiffness.

Moisture is where wool does something genuinely unusual. It takes water vapor into the interior of the fiber while the surface still feels dry, so it can carry a meaningful share of its own weight in moisture before it feels damp, then release that moisture slowly. That’s why wool tends to stay comfortable across a wider range of temperatures than most fibers. It also resists odor buildup better than synthetics.

How it wears

Wool has two honest weaknesses worth knowing about.

The first is pilling. Soft, fine, loosely spun knits can pill noticeably in the first few weeks as short fibers work their way to the surface and tangle. That early shedding usually settles down, and tightly spun worsted yarns pill far less than fluffy woolen-spun ones.

The second is felting. Heat, agitation, and moisture together can lock the fiber’s surface scales, and a felted sweater doesn’t come back. Machine-washable wool has been treated to reduce that behavior.

Abrasion resistance is decent, better in worsted suiting than in a loose knit, which is why sock makers often reinforce heels with nylon. Wear testing is coming to verified garments in Lynen; until then, construction is your best clue to how a wool piece will hold up.

Why does wool itch?

It comes down to fiber diameter, not wool itself. Coarser wool fibers are stiff enough that when they press against your skin, they don’t bend, and that mechanical prickle is what most people describe as itchiness. Because it comes from the fiber’s diameter, it’s different from an allergy: a physical effect rather than an immune one.

Finer grades bend against your skin instead of pressing into it, which is why people who can’t wear a coarse sweater are often perfectly comfortable in fine merino.

Wool also moves moisture vapor away rather than trapping it against your body, so it helps you avoid the warm, damp conditions that can make skin feel more reactive. This is general wellness information, not medical advice. If wool regularly bothers your skin, talk with your dermatologist.

What micron count stops wool feeling itchy?

Wool research generally places the prickle threshold at roughly 30 microns. Fibers coarser than that are stiff enough to press into skin rather than bend against it, and a yarn only needs a small share of them for the whole fabric to feel itchy.

Fine merino is typically graded between about 17 and 24 microns, with superfine grades under 18.5. That’s why a merino base layer feels nothing like a coarse boot-sock wool.

Few labels print a micron count, but wording like “superfine,” “extra fine,” or “17.5 micron” is one of the rare marketing lines that maps to a measurable property.

On the label

Wool carries a price premium, which can make it a target for substitution, and cashmere faces the same pressure at an even higher price. The most common blends pair wool with acrylic (cheaper, but it pills more), with nylon (added for abrasion resistance), or with elastane. A “wool blend” label with no percentages tells you very little, so look for the actual numbers.

Blends are also where label accuracy drops. In the EU market-surveillance campaign published in June 2026, inspectors tested 132 garments across eight countries and found that blend labels failed 64% of the time, compared with 15% for single natural fiber claims. A scarf sold as wool that turns out to be mostly acrylic is one common example.

Care that extends it

Wash wool rarely and gently. A sweater often freshens up with a night on a hanger in moving air, and every wash cycle is another chance for felting. When you do wash, use cool water, a wool detergent, and minimal agitation. Don’t wring it out, and dry it flat.

One more tip: store wool clean. Moths are drawn to protein and tend to find soiled spots first.