Somewhere between the flax field and the loom, the fibre intended for a fine shirt is drawn through a trough of warm water. It is a brief step in a long process and it is rarely mentioned on a label, yet it accounts for much of the difference between linen that feels smooth against the neck and linen that feels like good sacking. The result is known as wet-spun linen. Understanding it explains why two cloths that are both honestly called pure linen can have so little in common in the hand.

The reason lies in the structure of the fibre. A strand of flax, as it comes from the stem, can approach a metre in length, but it is not a single fibre. It is a bundle of much shorter cells, each only a few centimetres long, bound to one another by natural gums, chiefly pectin. After the plant has been retted and the woody core broken away, the strands are combed. The long, aligned fibre that remains is called line; the shorter fibre combed out is called tow. Why length matters is the subject of long-staple linen fibre.

Spinning means drawing those fibres out into a thinner and thinner strand and then twisting them so that they hold. In dry spinning this is done with the fibre as it is. The bundles are still glued together, so they cannot slide past one another very far, and there is a limit to how thin the yarn can be drawn. Dry-spun yarn is consequently thicker, more irregular and hairier, with fibre ends standing out from its surface. It has its own uses and its own beauty, in furnishing cloths, heavy table linen, canvas and twine, and tow is commonly spun this way.

Wet spinning changes one thing. Immediately before it is drawn out, the prepared strand, called a roving, passes through warm water. The warmth and moisture soften the pectin that holds the short cells together, and for a moment the cells are free to slide. The spinner's rollers can then draw the strand far finer than dry fibre would allow, and when the yarn dries the gums set again and lock it in its new form. The method was worked out in France and England in the early nineteenth century, and it is what first made fine linen yarn possible by machine.

The yarn that results is different in four ways. It is finer, so a lighter cloth can be woven from it. It is smoother, because the fibre ends are bound into the body of the yarn instead of standing out. It has more lustre, since a smooth surface reflects light evenly. And it is strong for its thickness, which allows a close, stable weave. Yarn fineness in linen is expressed as a count, a subject covered in linen thread count. As a rule, linen fine enough for shirting is wet spun from line fibre, whether or not anyone says so.

Since labels seldom mention it, the hand is the guide. Wet-spun linen feels cool and smooth when drawn across the inside of the wrist, with little of the prickle that puts some people off the fibre; that question is taken up in is linen itchy. Held to the light, the weave is clear and the threads are distinct. Looked at along the surface, few stray fibres stand up from it. Slubs are still present, because they belong to flax and not to any one method, but they are small and well bound. A cloth that is fuzzy, thick and uneven is not necessarily poor. It has simply been made for another purpose than a shirt.

What the house states is the origin of its principal cloth: certified Belgian linen, with a certificate that follows the flax from the field through to the weaving, as explained in what the Belgian linen certificate is. The practical advice is the same as for any linen. Handle it. The Bliss Linen Shirt and the Laos Long Sleeve Linen Shirt, in the PP linen shirts collection, are garments on which a reader can try every test in the previous paragraph.

For the wearer, the benefit is felt from the first day and grows. A fine, smooth yarn makes a cloth that is comfortable against the skin without needing to be broken in, and washing then softens it further as the remaining gums relax, year after year. It is still linen: it creases, and it has texture. Wet spinning does not turn flax into something else. It lets the fibre become as fine as it is capable of being, which is what a shirt requires of it.

How Linen Is Made, from the Flax Field  ·  Linen Slubs  ·  How to Identify Premium Linen