Walk into any outdoor shop and you'll see "merino" on a lot of labels. Turn the swing tag over, though, and many of those shirts aren't all merino. Some are 87% wool. Some are 79%. A few are less than half.
Blends aren't a con. They exist for good reasons, and for some people they're the right pick. But they're a different product from 100% merino, and you should know what you're paying for.
What a merino blend is
A merino blend mixes wool with a synthetic fibre, almost always nylon or polyester. There are two common ways to do it:
- Core-spun yarn: a thin nylon thread runs down the middle of each yarn, wrapped in merino. You see and feel wool on the outside, with nylon inside for strength. Mainstream shirts made this way are often around 10 to 20% nylon.
- Blended fibres: wool and synthetic fibres spun together. Some newer fabrics go much further, with more synthetic than wool, such as 57% nylon to 43% merino.
Why brands blend
- Strength: nylon is tougher than fine wool, so a blend usually resists holes and abrasion better. Brands that use a nylon core advertise stronger, more tear-resistant fabric.
- Lighter fabric: a nylon core lets a knitter make thinner fabric that still holds together.
- Cost: synthetic fibre is cheaper than superfine wool, so blends can cost less to make.
- Faster drying: the more synthetic in the mix, the quicker it dries.
What you give up
Every percent of nylon or polyester is a percent of the shirt that isn't doing merino's job:
- Odour resistance: merino's big trick is not stinking after days of wear. Synthetic fibres hold odour more, so a heavily synthetic blend can lose some of that edge.
- Comfort when you sweat: merino takes up moisture vapour into the fibre before it feels wet. Polyester and nylon take up very little, so the more synthetic there is, the more a shirt behaves like a synthetic one.
- Feel against the skin: core-spun blends keep wool on the surface, so many feel just like merino. Fibre blends with a lot of synthetic often feel slicker or more plasticky.
- End of life: 100% wool is a natural fibre. Blends are much harder to recycle and don't break down the way wool does.
Why we make ours 100% merino
Our hiking shirts are 100% superfine Australian merino, at 18.4 micron, made in Melbourne. We chose not to blend because the things merino does best are the things we want most on a multi-day walk: wearing the same shirt for days without the smell, and staying comfortable when the weather turns.
The honest trade-off is durability. A 100% merino tee needs a bit more care than a blend. Treated well, it lasts for years, and our guide to why merino gets holes covers how to keep it going.
How to read a merino label
- Find the percentage. "Merino" on the front means nothing on its own. Check the fibre content: is it 100% merino, or 87%, 70%, 43%?
- Look for a micron count. It tells you how fine, and how soft, the wool is. Many brands don't publish one. Ours is 18.4.
- Check where it's made. It's harder to know how the wool was grown and treated when it isn't stated. Ours is mulesing-free Australian wool, knitted, dyed and sewn in Melbourne.
- Match it to how you hike. Rough scrambles and heavy packs every weekend? A blend may suit you. Multi-day walks, travel and long days in one shirt? 100% merino is worth it.
Our 100% superfine merino hiking shirts come in short and long sleeve, in men's and women's fits. If you're still deciding, read our honest comparison of merino vs synthetic hiking shirts.
Sources: Blend ratios used by outdoor brands (Outlier) · A long-term review of a 57% nylon merino blend (Andrew Skurka) · Nylon-core merino and durability (Woolmark)
