Fiber diameter: the secret to comfort
Why does one wool sweater itch and another not? It all comes down to the fiber diameter, measured in microns. A key concept for choosing the right wool for the intended use.
If you've ever worn a sweater that "itched" and another, also made of wool, that glided over your skin like a caress, you've already experienced a technical concept without even knowing it: fiber diameter. This measurement, expressed in microns—a tiny unit equivalent to one millionth of a meter—is probably the most important piece of data for understanding why two types of wool can behave so differently.
The smaller the fiber diameter, the finer, more flexible, and more pleasant it is against the skin. This explains why some very fine wools are preferred for garments worn directly against the skin—underwear, scarves, baby clothes—while coarser fibers naturally find their place in carpets, felts, or insulation materials, where softness is less important than robustness.
For experienced spinners, this notion quickly becomes a practical tool. Even before spinning, one can anticipate the final use of a batch simply by assessing its fineness by touch, or by consulting precise measurements when available. This is a skill that develops over time, and that distinguishes thoughtful craftsmanship from work done blindly.
It's important to understand that fiber diameter is not a matter of "superior" or "inferior" breed—but rather suitability for use. A coarser wool, perfectly suited for a sturdy rug or a protective felt for your flowerbeds, would be a poor choice for a delicate shawl; and the inverse is just as true. At Makeloo Studio, when we evaluate a new fleece from one of our partner farms, this is precisely the first analysis we make: what is this wool best suited for, even before thinking about processing it.
It is also this nuanced understanding that distinguishes the work of a meticulous artisanal spinning mill from undifferentiated mass production: each batch is evaluated for what it is, and directed towards the product that suits it best, rather than being forced into a single mold.
Source: The Woolmark Company, woolmark.com/fibre; International Wool Textile Organisation, Wool Notes, Issue 3 (2024).