By Jock Merriman, Founder of Sir W. Merino
I grew up on a Merino sheep farm in Boorowa, Australia—a town known more for the quality of its wool than the quantity of its Wi-Fi. For four generations, my family has lived and breathed Merino wool. I’ve felt it in the heat of harvest season and the chill of early mornings. I’ve seen the way our sheep adapt to Australia’s extremes—how their fleece keeps them cool under the burning sun and warm through icy winds. And I’ve seen firsthand what real quality feels like when it comes off the sheep’s back.
That’s why I started Sir W. Merino—to bring that same performance and softness to people who are tired of clothing that’s all promise and no payoff. But to understand the value of Merino, you’ve got to understand what it’s not. And that brings us to polyester.
I’ll be straight with you: polyester and Merino wool couldn’t be more different. One comes from a sheep; the other from a barrel of oil. One breaks down naturally; the other could outlive you in a landfill. One breathes, regulates, and comforts; the other… traps heat and smells like yesterday’s gym socks.
But let’s dive deeper. Here’s why Merino wool outperforms polyester in every way that matters—and why I’ll always bet on the sheep.
1. Origins: Nature vs Chemistry Lab
Let’s start with where each fiber comes from.
Merino wool is grown, not made. It’s a natural protein fiber—just like your hair—grown by Merino sheep, which have been selectively bred over centuries for their ultra-fine, soft fleece. These sheep thrive in environments that swing from 100°F to below freezing. Their wool is nature’s own form of climate control.
Polyester, on the other hand, is a synthetic fiber made from petroleum. It’s plastic. To create polyester, manufacturers extract crude oil, refine it into ethylene, polymerize it into PET (the same material as plastic bottles), then melt and extrude it into long threads. It’s efficient, sure. But it’s hardly natural—and its long-term impact on the planet is anything but.
When you wear Merino, you're wearing something regenerative. When you wear polyester, you're wearing something derived from fossil fuels. That should tell you a lot right off the bat.
2. Comfort: Breathability, Temperature, and Touch
If you’ve ever hiked in a polyester t-shirt, you probably know what I mean when I say it feels like wearing a plastic bag. Sure, it might be lightweight. But plastic doesn’t breathe.
Merino wool is different. Each fiber has a natural crimp and structure that allows it to create tiny air pockets for insulation and breathability. This means it keeps you warm when it’s cold and cool when it’s hot. It's thermoregulation in action, the same way it works for the sheep on our farm.
Merino can absorb up to 35% of its weight in moisture without feeling wet. It pulls sweat away from your skin and lets it evaporate—keeping you dry, comfortable, and far less clammy than polyester ever could.
Then there’s the feel. People assume “wool” means itchy. That’s because most folks only know thick, coarse wool from cheaper breeds or scratchy sweaters. Merino is different. The fibers are incredibly fine—often just 17–19 microns, which is finer than human hair. That’s why it feels soft, smooth, and wearable even right against your skin.
Polyester? It can be engineered to feel soft, but it always has that unmistakable synthetic slickness. And when you start to sweat, it clings. Not ideal.
3. Odor Resistance: Stay Fresh Longer
Here’s something hikers, travelers, and gym-goers love about Merino: it resists odor naturally.
The fiber’s complex structure absorbs the bacteria that cause body odor and traps it until you wash the garment. Even better, the lanolin in the wool has natural antibacterial properties. This means you can wear a Merino shirt for days—sometimes even weeks—without it smelling. I’ve done it myself on long-haul flights and treks, and it’s a game changer.
Polyester, on the other hand, has a reputation: stink. It traps sweat and bacteria on the surface, and washing doesn’t always remove the smell. Over time, that gym shirt builds up a permanent funk. That’s not something you want to carry around.
Merino doesn’t just hide odor—it prevents it.
4. Sustainability: The Real Impact
This is where the differences become not just personal—but global.
Merino wool is 100% renewable and biodegradable. Every year, our sheep grow a new fleece. Every year, we shear it off without harming them. When a Merino garment finally wears out—after years of use—it will break down naturally in soil, returning nutrients back to the earth.
Polyester is plastic. It doesn’t break down. Instead, it sheds microplastics—tiny synthetic fibers that wash into our oceans every time you do your laundry. These particles are being found in fish, sea salt, drinking water—and even inside human bodies. The long-term health effects are still being studied, but the environmental damage is already clear.
What’s more, polyester’s production is energy-intensive and heavily reliant on fossil fuels. If we’re serious about reducing our impact on the planet, choosing natural, renewable fibers like Merino is an easy win.
5. Durability and Longevity
People sometimes ask: “Isn’t wool more delicate than synthetic fibers?” It’s a fair question. But Merino wool isn’t your grandmother’s knitting yarn. It’s surprisingly strong, especially when spun and knit the right way.
At Sir W., we design our garments to last. With proper care—gentle washing, air drying—Merino shirts can last years, even with regular wear. And unlike polyester, which can pill, fade, or lose shape, Merino holds its form beautifully.
Sure, polyester won’t biodegrade anytime soon, but that doesn’t mean it keeps looking good. Many synthetic garments wear out fast and get thrown away—not because they disintegrate, but because they look and feel worse over time.
With Merino, you invest in quality. With polyester, you often get quantity—but at what cost?
6. Performance: Outdoor, Everyday, and Travel
When I started Sir W., my goal wasn’t just to make beautiful Merino garments. I wanted to make pieces you could live in—whether that’s exploring a city, hiking a mountain, or heading to the office.
Merino transitions effortlessly. It’s breathable enough for summer, warm enough for winter, and refined enough to wear just about anywhere. It resists wrinkles, which makes it ideal for travel. It dries quickly. And because it stays fresh, you don’t have to pack five shirts for a three-day trip.
Polyester has its place—especially in fast fashion and hyper-specific performance gear. But for most people, most of the time, it just can’t match the versatility and elegance of Merino.
7. Care and Maintenance
One area where polyester might seem to win at first glance is care. You can toss it in the wash, throw it in the dryer, and forget about it. But what are you really getting? A shirt that stinks sooner, pills quicker, and ends up in landfill faster.
Merino does require a bit more mindfulness. Cold wash, gentle detergent, and hang dry—that’s usually all it takes. But the payoff is massive. You’ll wash it less often, and it’ll still look (and smell) fresh.
In fact, over time, Merino can actually require less maintenance than polyester simply because you don’t need to wash it as often.
8. Cost: The True Price of Clothing
Yes, Merino costs more. Let’s talk about why.
It takes time, skill, and care to raise Merino sheep and process their wool. Each fleece is shorn once a year. It must be cleaned, spun, and carefully woven into garments. And we pay for quality, ethical farming, and sustainable practices.
Polyester is cheap because it’s mass-produced from oil. It’s fast, it’s industrial, and it’s designed to be disposable.
When you buy Merino, you’re investing in something better—for you and for the planet. You’re saying no to disposable fashion, no to plastic clothes, and yes to comfort, quality, and longevity.
And if you're anything like me, you'll find that once you own a couple of Merino pieces, you need fewer clothes overall. They do more with less.
Why I Chose the Sheep
At the end of the day, this isn’t just a comparison between two fabrics. It’s a question of values.
Do you want to wear something natural, breathable, and renewable? Or something synthetic, stuffy, and polluting?
Do you want your clothing to support ethical farms and regenerative cycles? Or to contribute to microplastic pollution and oil dependency?
As someone who grew up watching sheep graze across golden hills, who’s spent years building a brand rooted in craftsmanship and sustainability, I know my answer.
At Sir W. Merino, we build garments that last. Garments that breathe, perform, and biodegrade. Garments that come from nature and return to it. Garments that feel like a second skin—because they were designed by evolution to do just that.
Polyester might be everywhere. But Merino is everything polyester wants to be—and more.
Thanks for reading. And if you haven’t already—try on a Merino shirt. You might just change your wardrobe forever.
Written by Jock Merriman, founder of Sir W. Merino. Raised in Boorowa, NSW, Jock created Sir W. to bring the best of Australian Merino to wardrobes around the world—one soft, sustainable shirt at a time.