When I'm out and about trumpeting the amazing properties of wool, I often get told wool is "itchy" to wear.
The biggest factor as to whether a particular wool is soft or harsh to the touch is the diameter of the individual fibres. The measurement used for this is called a micron (or micrometer). One micron is one millionth of a metre, or one thousandth of a millimeter.
Sheep’s wool can range from 11 microns to well over 40 microns depending on the breed and the age of the sheep. Younger sheep will have finer wool – the fibres get thicker as the sheep ages. This is why we often use lambswool for blankets and other woolen products for babies.
The micron is also determined by the type of wool. A merino fibre is usually under 24 microns, and most merino clothing is actually made from wool less than 20 microns. To give you an idea of how small that is, a human hair is on average around 100 microns wide!
The wool yarn we use in our fabric with Inter-weave (after a lot of trial and error) is a combination of 22 and 28 microns, which gives a softer feel, but still uses yarn from "strongwool" breeds in New Zealand (check out breeds in NZ here).
Scientists have determined that wool which is thicker than 30 microns is strong enough to press on human skin and excite the nerve receptors just below the skin – this is the main cause for what we all know as 'the wool itch'.
The great news is that modern wool manufacturing has all but eliminated the itchier wool garments, and because we line our coats with comfortable, breathable cotton, you'll never feel "itchy" but will have all the wonderful properties of owning a garment made from 100% New Zealand sourced wool!