How to read a cashmere label in ninety seconds

Cashmere is the undercoat of a goat, combed out in spring, and the entire quality question is decided in the first ten minutes after it leaves the animal. Everything afterwards, including the label, the boutique and the price, is commentary on a decision that was taken by a sorter in a shed.

The two numbers, and why you never see them

Fibre diameter is measured in microns and decides softness. Under 15.5 is the range that reads as luxurious on the neck. At 16 to 16.5 you are in respectable commercial territory. Above 17, the fibre begins to feel like fine wool, which is a perfectly good thing to be but not what the word on the label is charging for.

Staple length is measured in millimetres and decides everything else. A long fibre, 34 mm and above, has enough length to be twisted securely into the yarn and stays there. A short one, under 30 mm, has ends that migrate to the surface with every movement, and those ends are what you are looking at when a jumper pills into grey fuzz by February. Short fibre is cheaper because it is what is left after the long fibre has been sorted out, and it is graded as cashmere with complete legality.

Neither number appears on any label sold at retail. The mills know them precisely and the shop that sells the finished garment usually does not know them at all. Which is why the test has to be done in the hand.

The four tests, in order

• Stretch the cuff or the hem across your palm and let go. Good cashmere returns. A knit with short fibre and loose twist stays where you put it, and that is exactly what the elbows and cuffs will do after ten wearings.
• Rub the knit briskly against itself for ten seconds where nobody will see it, inside the placket or the hem. If a small grey bloom of fibre ends appears, you have just watched six months of pilling happen in front of you.
• Hold it to a window. An even, close knit with no thin patches between stitches means the yarn was spun consistently and the garment was knitted rather than rushed.
• Weigh it in the hand and check the label for grams if it gives them. A two ply crew neck in a medium should feel substantial: 280 grams is light, 340 is normal, 400 and above is a proper winter knit. Anything under 250 in a medium is either single ply or very loosely knitted, and both mean a short life.

Ply, which is not thickness

Ply counts the strands twisted together to make the yarn, not how thick the finished cloth is. A two ply yarn knitted finely gives a light garment that still resists abrasion, because the twist locks the fibre ends in. A single ply knitted thickly gives something that feels lovely for a month and then thins at every point of friction: underarm, elbow, the place where a seatbelt crosses.

Most of the genuinely disappointing cashmere sold at serious prices is single ply made from short fibre, sold on the hand feel of a heavy finishing treatment that washes out. The finishing is the trick: brushing and softening chemistry can make almost anything feel like the good stuff on a hanger. It survives roughly two washes.

The hand feel in the shop is a claim about the finishing. The hand feel after three washes is a fact about the fibre.

What price does and does not tell you

Below about 150 for a crew neck, the arithmetic of buying long fibre does not work, and something has been given up. Between 150 and 400 the correlation between price and fibre quality is real but noisy, and this is exactly the range where the hand tests earn their keep. Above 400 you are paying for design, finishing, provenance and the shop, and the fibre may be identical to a knit at half the price from a mill two valleys away.

The uncomfortable version of that sentence is that the same Inner Mongolian clip, spun at the same Italian mill, goes out under labels with a fivefold price difference between them. What differs is the cut, the trims and the story. Sometimes those are worth it. They are just not the fibre.

Keeping it alive

Cashmere is destroyed by friction and heat, not by wear. Three habits carry a knit through a decade.

• Wear it twice, then rest it for a day. The fibres recover their loft and the garment keeps its shape.
• Wash it, do not dry clean it. Cool water, a wool detergent, two minutes of gentle movement, no wringing, dried flat on a towel. Solvent strips the natural oils that keep the fibre elastic.
• Fold, never hang. A hanger puts the whole weight of the knit on two points of the shoulder, and the shoulder is where it will show.
• Depill with a comb rather than a razor. A comb lifts the bobbles off, a blade cuts into the surface and creates the next generation of loose ends.

Done that way, a good knit does not wear out. It goes soft, loses a little of its original crispness, and stays in rotation for fifteen years. That is a cost per wear of well under two, which is why the fibre deserves the attention.

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