A Class on Knit Yarn: Cashmere, Merino, and the Truth About Pilling

Knitwear is the category most often gotten wrong in autumn and winter. Two sweaters both labeled "100% wool" - one soft and kind to skin, the other scratchy and pilling; a "cashmere" piece that thins to paper in one winter beside one that grows more supple with every wash. The problem is that few people distinguish the yarn types: cashmere, merino, mohair, and lambswool are not the same thing, and their warmth, price, and care differ enormously.

This is a compact yarn class: four mainstream animal fibers taken one by one, then the real cause of pilling (not simply "poor quality") and the matching wash rhythm. After reading, you should be able to judge at the shelf, by hand and by tag, whether a knit is worth its price.

Cashmere: the lightest, warmest soft gold

Cashmere comes from the fine undercoat next to a goat's skin; each animal yields only 100-200 grams a year, which is why it is dear. The fiber diameter is 14-16 microns, nearly half that of wool, so it is soft without scratching. Its warmth per weight is about eight times that of wool, yet it weighs far less. A quality cashmere sweater runs about 200-280 g (men's) and costs 800-3000 yuan ($110-$420).

To spot real cashmere: genuine fiber burns with a hair smell and the ash is brittle and crumbly; synthetics smell of plastic and clump hard. By hand, real cashmere feels cool and springs back slowly with a supple, nuanced hand; fake cashmere feels slick and returns fast. Note that "cashmere-feel" is not cashmere - much of it is wool with softener that reverts after two washes.

Merino: the all-rounder for sport and daily wear

Merino is a fine-wool breed with a diameter of 17-23 microns; the superfine subset (17-19 microns) already approaches cashmere touch. Its great advantage is temperature regulation: it traps warmth when cold and wicks when hot, and is naturally antibacterial, so it can be worn days without odor - which makes it the first choice for sleeveless base layers and daily underlayers. Merino sweaters run 300-1200 yuan ($42-$166).

Merino splits into mercerized and unmercerized. Mercerizing makes the yarn shinier and slightly more pill-resistant but loses a little loft. Choose by micron: under 19 microns suits direct skin contact; above 21 microns is a touch scratchy and better as outerwear. It is cashmere's affordable substitute, and on all-round performance often beats it.

Cashmere also splits into worsted (fine, smooth, for light base layers) and woolen (lofty, thick, for outer sweaters). Two pieces both "100% cashmere" differ: woolen is heavier and reads luxurious; worsted is light and close. Decide before buying whether you want a base layer or an outer piece, then choose the spin - do not let the three words "pure cashmere" lead you.

The tempers of mohair and lambswool

Mohair comes from the angora goat; the fiber is long with a natural sheen, giving a halo glow, but woven alone it loosens, so it is usually blended (mohair 30% + wool 70%) for structure. It is light, warm, and structured but delicate, with high care demands. Lambswool is the first clip of a lamb under one year, about 20 microns - softer than adult wool but scratchier than cashmere - priced accessibly at 200-500 yuan ($28-$70).

A common mistake is treating lambswool as the cheap version of cashmere; it is only young sheep's wool, inferior in warmth and softness. Mohair sweaters pill mostly from a wrong blend ratio or too-coarse yarn; a 30% mohair blend pills less and holds shape better than pure mohair.

• Cashmere: 14-16 microns, softest and priciest, tiny annual yield
• Merino: 17-23 microns, regulates temperature and resists odor, sport first choice
• Lambswool: about 20 microns, young-sheep wool, cheap and slightly scratchy

The truth about pilling: friction, not poor quality

Pilling works like this: short fibers break under friction and roll to the surface into balls. So yarns rich in short fiber and high count (cashmere, high-count wool) actually pill more - it is a material property, not a defect. Polyester and other filaments do not pill but are stuffy. The standard: light pilling is normal; severe sheet pilling means poor yarn or low twist.

To reduce pilling: cut friction against rough fabrics (denim, canvas); wash inside out in cold water by hand; use a fabric shaver to clear pills regularly - never tape, which tears fibers. After pilling, just cut the balls off; they will not multiply, as long as the fiber is not ground through - clear the surface and it stays clean.

Detergent must be wool-specific (neutral pH, enzyme-free); ordinary laundry liquid is alkaline and damages protein fiber, hardening the loft. Hand-wash below 30 C, press do not rub, rinse and roll in a towel to absorb water, then flat-dry. Machine washing must use a bag and the wool program with under one minute of spin. Wash care right or wrong decides whether a knit lasts three years or three seasons.

Heavy pilling signals short, soft fiber - quite possibly good cashmere.

Stitch, weight, and knit fit

Stitch affects thickness and drape. Jersey is thinnest and closest, for base layers; rib is elastic and shaping, common at hems and cuffs; cable is thick and dimensional, warm but bulking; pique has a textured relief, structured without clinging. On weight, base layers run 180-240 g, outer sweaters 300-450 g.

On fit, watch shoulder and sleeve. A drop shoulder reads casual; a regular shoulder reads sharp. Sleeve length to the base of the thumb, showing a section of wrist is cleanest. For necklines, the turtleneck warms but demands neck length; the mock neck is friendlier; the V lengthens the neck and suits round faces. When buying, measure chest flat: a regular fit is net chest plus 8-12 cm of ease.

The wash rhythm that decides lifespan

Animal fiber fears hot water, machine agitation, and sun. Correct washing: cold (below 30 C), wool-specific neutral detergent, gentle inside out, never wring, flat-dry in shade (hanging stretches and deforms). Frequency: cashmere two to three times a season is enough; rest a day between wears so the fiber recovers. In storage, fold rather than hang, and add a moth-repelling sachet (cedar beats mothballs, which damage fiber).

Wool sweaters mostly shrink from hot water or machine washing; buy only "machine-washable wool" (the symbol with a circle and hand) in mercerized shrink-resistant wool for peace of mind. If cashmere shrinks to child size, it is essentially unrecoverable - so the first wash must be by hand. Remember: a knit's life is half in the buying, half in the washing.

For storage, do not rely on mothballs alone: para-dichlorobenzene smells and residues damage fiber; cedar blocks or lavender sachets are safer. Fold with the body flat and sleeves turned in, avoiding long pressure on the shoulders. When taking out at season change, air for half a day before wearing to clear mustiness and check for insect traces.

Gauge and the visual of stitch density

Knit gauge is stitches per inch: 12G is fine and smooth, 7G chunky in texture, below 5G heavy. Fine gauge (12G+) suits merino and cashmere base layers, close without showing pattern; chunky gauge (below 7G) suits wool and mohair outer pieces with strong texture.

Gauge also decides pilling: chunky uses thick, long fiber and pills less; fine high-count soft yarn, with short fiber, pills more. So the same cashmere in a chunky cable wears better than in a fine jersey. Buy outer thick pieces around 7G, base layers around 12G - reverse-engineer from use, not from style.

Cashmere blends are common: cashmere 30% + wool 70% (value), cashmere 50% + wool 50% (soft-warm balance), pure cashmere (ultimate). A silk blend (cashmere 70% + silk 30%) adds sheen and drape but costs more. Merino blends often add 5-10% nylon for abrasion. Price anchors: pure cashmere men's 800-3000 yuan ($110-$420) is fair; a 30% cashmere blend 300-800 ($42-$110); merino 200-800 ($28-$110). A "cashmere sweater" under 200 yuan ($28) is basically wool-blend fake or trace content. Read the percentage on the composition label, not the "cashmere-feel" wording, which is marketing not composition.

The essence of knitwear is the yarn, not the style. First fix four fibers in your head: cashmere is soft and pricey, merino is the all-rounder, mohair is sheen and delicate, lambswool is cheap and slightly scratchy. Then remember that pilling is not a defect but a property of short fiber - de-pilling beats anxiety. Finally treat care as an investment: the three moves of cold water, flat-dry, and folded storage mean an 800-yuan ($110) cashmere lasts five years, while an 800-yuan cashmere washed carelessly lasts one winter. Buy knitwear by asking yarn before cut; get the order wrong and you pay tuition. One more: gauge is the hidden selector - 12G for base layers, 7G for outer; reverse-engineer from use beats reading style. Hold yarn and gauge together and knits stop being luck. And a note: worsted versus woolen decides cashmere's use, and care decides its life. String yarn type, spin, and care together and a knit truly earns its keep.