Three jumpers hang side by side. One says merino, one says lambswool, one says virgin wool. They cost different amounts, they feel different in the hand, and almost nobody buying them could explain why. The labels are not marketing language. Each one describes something specific about where the fibre came from and how it will behave over the next ten years.

Understanding them takes about ten minutes and changes how you buy knitwear and coats permanently. What follows is the whole vocabulary, in the order it becomes useful.

Where wool comes from

All wool is hair, grown by sheep to regulate their own temperature. What makes it extraordinary as a textile is the structure of a single fibre: a scaled outer layer, a crimped core that holds air, and a natural waxiness that resists water until it is thoroughly soaked. Air trapped between crimped fibres is what keeps you warm. The wool itself is not warm. The air it holds is.

That crimp also explains elasticity. A wool fibre can be stretched by a third of its length and return. This is why a wool coat recovers its shape after a day of sitting, why a jumper does not hold the imprint of a seatbelt, and why wool creases so much less readily than linen or cotton. The fibre is, in effect, a spring.

Breed determines everything that follows. A sheep bred for meat grows coarse, strong wool suited to carpets and outerwear. A sheep bred for fleece grows fine, soft wool suited to things worn next to skin. The names on labels are mostly describing which end of that range you are holding.

Two further properties are worth knowing, because they explain decisions that otherwise look arbitrary. Wool is naturally flame resistant, which is why it has been used for blankets and uniforms for centuries and why it chars rather than melts. It also holds dye deep inside the fibre rather than on the surface, which is why good wool keeps its colour through years of wear while cotton of the same age looks washed out. Both properties come from the same scaled, absorbent structure.

Micron count, plainly explained

A micron is one thousandth of a millimetre, and it measures the diameter of a single fibre. This single number predicts softness more reliably than price, brand or country of origin.

Above roughly 30 microns, the fibre is stiff enough that its ends press into skin rather than bending against it, and that pressure is what people call itch. Between 24 and 30 microns you are in standard wool territory: hard wearing, warm, fine for a coat or an outer layer, not for a bare neck. Between 19 and 23 microns, wool becomes comfortable against skin for most people. Below 19 microns it is luxurious, and below 16 it is rare and priced accordingly.

Itch, in other words, is a mechanical property, not an allergy. Most people who believe they cannot wear wool have only ever worn coarse wool. A fine merino at 18 microns against the same skin feels like nothing at all.

One caution about the number. Micron count is an average across a whole fleece, and averages hide variation. A yarn quoted at 21 microns may contain a small percentage of fibres at 30, and that small percentage is exactly what you feel. This is why two garments with identical stated counts can feel quite different, and why the only reliable test is the one you perform yourself with the cloth against your own skin.

Merino

Merino is a breed, not a process. The sheep originated in Spain and are now farmed principally in Australia and New Zealand, bred over centuries for one quality: fineness. Merino fleece typically falls between 15 and 24 microns, which puts almost all of it in the comfortable range.

What makes merino unusual is the combination of fineness and crimp. The fibres are thin enough to bend against skin and crimped enough to hold air, so the cloth is simultaneously soft, warm for its weight and highly breathable. It also manages moisture better than any synthetic: a merino layer absorbs a third of its weight in water vapour before it feels damp, which is why it stays comfortable through temperature changes and long days.

The trade off is durability. Fine fibres are, by definition, weaker fibres. A lightweight merino jumper worn twice a week will show wear at the elbows before a lambswool one will. It belongs in the layers closest to the body, where softness matters, rather than in the outer layers that take abrasion. A Jumper TS006 worn under a coat is doing exactly the job merino is built for.

Merino also comes in weights that have nothing to do with fineness. The same fibre spun to a fine gauge gives a layer thin enough to wear under a shirt. Spun heavier, it gives a jumper that works on its own. Judging a merino garment means reading both numbers, the micron count for comfort and the gauge for warmth, and the second is the one most people forget to consider.

Lambswool

Lambswool is the first shearing of a sheep, taken at around seven months. It is not a breed and not a grade. It is an age.

First fleece has never been cut, which means every fibre still has its natural tapered tip rather than a blunt sheared end. Blunt ends are what press into skin, so lambswool feels softer than its micron count alone would predict. It is also longer and more elastic than later fleece from the same animal, which makes it spin into a smoother, stronger yarn with less tendency to pill.

In practice lambswool sits in a useful middle position. It is softer than standard wool, more robust than fine merino, and it holds structure well enough for outerwear while staying comfortable enough for a jumper. If you want one wool to do several jobs, this is usually it. The quantity is limited by biology, since each animal produces exactly one first fleece, which is why it costs more than ordinary wool and less than the finest merino.

One practical note on buying it. Because lambswool is defined by the age of the animal rather than by any measurable property of the fibre, the term is loosely policed in some markets. Treat it as a useful signal rather than a guarantee, and let the hand tests below settle the question.

Virgin wool and recycled wool

Virgin wool means wool that has never been processed into a textile before. The term exists because the alternative exists: wool can be recovered from old garments, shredded back to fibre and respun. Recycled wool is a genuinely good thing environmentally, but the shredding breaks fibres into shorter lengths, and short fibres make weaker, fuzzier yarn that pills sooner.

So virgin wool on a label is a statement about fibre length and strength rather than about luxury. It does not mean fine. A coarse carpet wool can be virgin wool. What it guarantees is that the fibres have their full original length and have not been damaged by mechanical recovery.

In outerwear this matters more than anywhere else, because a coat lives through rain, friction and years of wear. A Coat 02 made from long staple virgin wool will hold its surface and its shape for a decade. The same coat in recovered fibre will bloom and pill within two winters. The difference is invisible in a shop and obvious by the third season.

Recycled wool is still worth choosing in the right place. In a heavy winter coat, where the cloth is thick and the garment sits over other layers, the shorter fibre matters far less and the environmental case is strong. The error is buying recovered fibre in a fine jumper worn against skin, where every weakness in the yarn is exposed within a single season.

Judging quality by hand

There are four tests and none of them requires a label. The first is weight against warmth. Pick the garment up. Good wool feels lighter than it looks, because fine crimped fibres hold air rather than mass.

The second is recovery. Take a handful of the cloth, squeeze hard for three seconds and release. Good wool springs back almost completely within a few seconds. Poor wool, or wool blended heavily with short fibre, holds the crease and relaxes slowly.

The third is surface. Hold the fabric to the light at an angle and look for a halo of loose fibre ends standing proud of the surface. A faint halo is normal. A visible fuzz means short fibres, which means pilling is coming. The fourth is the back of the neck. Press the cloth against the skin below your jaw rather than the palm of your hand, which is far less sensitive. If it is comfortable there, it is comfortable anywhere.

Price correlates with these qualities only loosely. A Coat 01 is worth judging by the same four tests as anything else on the rail, and so is everything in the MINIMAL collection.

Caring for each

Wool needs washing far less often than people assume. The fibre resists odour and releases dirt readily, so airing a jumper overnight does most of what a wash would do. Over washing is the single largest cause of wool garments wearing out early.

When you do wash, cool water, a detergent made for wool and almost no agitation. Heat and movement together cause felting, which is permanent: the scales on the fibre surface lock into one another and the cloth shrinks and thickens irreversibly. Fine merino is the most vulnerable, lambswool is more forgiving, and heavy virgin wool outerwear should generally go to a specialist rather than into water at all.

Dry flat, always. Wet wool is heavy and the fibre is at its most extensible, so a hanging garment will stretch under its own weight and stay stretched. Store folded rather than hung for the same reason, and store clean, since moth larvae are drawn to the traces of skin and food rather than to the wool itself. Shawls and scarves such as a Shawl 03 keep best folded flat with space around them. The same principles govern silk care, and the opposite case, a fibre that is meant to crease, is set out in why linen creases.