On Merino — A Wool Worth Keeping
"Wool" is a word doing a lot of work. Carpet underlay is wool. A scratchy school jumper is wool. The 18.5-micron merino in our slipper-socks is also wool. Here's the part of the conversation worth having.
The most useful number in any wool conversation is the micron count. It measures the average diameter of a single fibre — and it predicts almost everything: softness, scratch, drape, durability, price. Lower numbers are finer and softer; higher numbers are tougher and rougher.
The micron map
A short, opinionated guide:
13–17 microns: Ultra-fine merino. The very best base layers, sold by weight in grams. Almost too fine to be put under load — beautiful next to skin, fragile under abrasion.
17.5–19.5 microns: Where most premium merino apparel lives — and where our Flinders Slipper-Sock sits. Fine enough not to itch on bare skin; dense enough to hold shape over years.
20–23 microns: "Crossbred" merino. The wool of choice for pressed felt — strong enough to be worked into a dense, seamless mat. Our Daintree Bootie is pressed from 21-micron crossbred.
24+ microns: "Strong" wool. Carpets, rugs, outerwear. Our Halls Gap Bedside Mat is loomed from 28-micron — it has to take a step every morning for years.
"You can't talk about wool without talking about microns. Everything else is decoration."
Why "Australian"
Australia produces roughly a quarter of the world's wool, and most of it is fine merino. The combination of climate (cold winters, dry summers), grazing (low stocking rates, native pasture) and breeding history (180+ years of selective work) produces a fibre that consistently sits one to two microns finer than the same breed elsewhere. The label "Australian merino" isn't marketing. It's a measurable difference.
What microns won't tell you
Two more numbers matter, even if they're less famous. Staple length: how long an individual fibre is, before being spun. Longer staples wear better. GSM (grams per square metre): how dense the finished fabric is. Heavier wool fabric is warmer, drapes more, and lasts much longer. Our slipper-sock is 240 gsm, which is on the heavy side for socks. That's deliberate.
An ending in plain English
If you're standing in front of a wool product, ask: what's the micron count? If the answer is anywhere under 20, you're looking at something that won't itch on skin. If it's between 20 and 23, you're looking at something pressed or felted that will keep its shape for years. If the brand can't tell you the number, the brand probably doesn't know the wool.