What Is Superwash Merino Wool? (and Why Hand-Dyers Use It)
Superwash is a treatment Merino wool goes through to smooth out the microscopic scales on the fiber hairs that cause shrinking and felting. The result is machine-washable wool that keeps Merino’s natural softness and warmth. Here at Bad Sheep Yarn, we use Superwash Merino as the base for most of our collections (Fingering, Sport, DK, Worsted, Bulky, Sock Tweed, Aran Tweed) because it holds hand-dyed color vividly and stands up to real washing. That being said, we do carry non-superwash yarn options as well, which we’ll explore later in the post.
What Is Superwash Merino Wool?
Superwash Merino wool is Merino wool that has undergone a treatment to prevent shrinking and felting in the washing machine. Untreated wool fibers have overlapping scales that lock together and shrink under heat, moisture, and agitation — this is what normally makes hand-washing necessary for wool. The superwash treatment smoothes out the microscopic scales on the fiber hairs that cause the shrinking and felting. While this process doesn't create softness, Merino wool specifically is valued as the base for this treatment because of its natural fineness and softness.
We have several beautiful hand-dyed yarn bases built on Superwash Merino in our studio:
- Fingering (75/25 Superwash Merino/Nylon)
- Sparkle Fingering (75/20/5 SW Merino/Nylon/Stellina)
- Sport (100% Superwash Merino)
- DK (75/25 Superwash Merino/Nylon)
- Worsted (100% Superwash Merino)
- Bulky (100% Fine Superwash Merino)
If you want to see each colorway up close, browse our Superwash collection. And if you want to go deeper with the full spec sheet for every base here, dive into our fiber information page.
How Does Wool Become "Superwash"?
Wool becomes superwash wool through a standard industrial process made up of four stages called the chlorine-Hercosett method. (Reference: Farm & Fiber Knits — "What Is the Superwash Process, and What Does It Do to Wool?") During stage one, wool passes through a chlorine solution that erodes the overlapping scales on the fiber surface. Then, at stage two, a neutralizing solution stops the chlorine's action. At stage 3, the wool is coated with a thin layer of a polymer resin called Hercosett, which smooths and seals the eroded surface. Finally, a softener is applied and the wool is dried to complete stage four.
All of this happens in a textile processing facility well before the wool reaches the Bad Sheep Yarn studio to take a dip in our dye pots. Then we get to do what we do best: channel our creativity into small-batch, hand-dyed skeins to share with crafters near and far! We've heard some makers have environmental or processing concerns with the superwash treatment, and we understand that — that's why we also carry non-superwash skeins.
Is Superwash Wool Machine Washable?
One of our most common customer questions is, "Can you put superwash merino wool in a washing machine?" Technically, yes, you can put merino wool in the wash on a cold, gentle cycle and dry it on the lowest setting. But that doesn't mean you actually should.
The superwash treatment makes machine washing possible, yes, and we've found that machine-washability is most useful for kids' and everyday items. That being said, our protocol is hand washing all finished projects before laying flat to dry, and we also advise blocking your merino wool project.
Since hand washing and air-drying are so gentle, your project will avoid wearing out too quickly, bleeding extra dye, and becoming mis-shapen. Hand washing also protects stitch definition, blocking, and hand-dyed color vibrancy over time on a labor-intensive finished piece. It's definitely worth the bit of extra time! For the complete washing protocol, read How to Wash Hand-Dyed Yarn.
Superwash vs. Non-Superwash — Why We Dye Both
We take time to dye both superwash Merino and non-superwash organic Merino in small batches at our studio. Here's the honest reason why: some stitchers want machine-washable ease (superwash), and others want the more traditional untreated woolly yarn (non-superwash). We honestly love them both for different reasons and see them as just different tools for different makers. There's no wrong choice when it comes to creativity!
Fans of superwash yarn celebrate it as the practical everyday choice. They love it for its machine-washable-friendly fiber and its even and vivid hand-dyed color uptake. Superwash is a multi-step process Merino wool undergoes to smooth the scales on the fiber hairs that normally cause shrinking and felting. Basically, superwash is the reason your honey can accidentally throw your sweater in the wash and it doesn't come out looking doll-sized. The treatment still preserves Merino's natural softness and warmth, which adds to its appeal.
Non-superwash yarn retains wool's natural, water-repellent scale structure — seriously, it is so moisture-resistant, we have to work really hard just to get it thoroughly soaked in the dye pots! It has excellent temperature regulation, strong shape retention for structured garments, and can be intentionally felted. Our non-superwash has certified organic sourcing, and we talk more about its features in this post, icymi: Introducing Non-Superwash Organic Yarn
Ready to feel wooly and wonderful inside? Discover your favorite colorway — explore our cozy non-superwash organic collection.
FAQ
Does superwash wool shrink?
No, the superwash treatment specifically removes the scale structure that causes shrinking and felting. This is why superwash-treated wool can technically go in the washing machine without being ruined.
Is superwash merino as warm as regular merino?
Yes. Even though the superwash treatment changes the fiber's surface, it doesn't eliminate its core insulating properties.
Why does Bad Sheep Yarn sell both superwash and non-superwash yarn?
We love them both and see them as different tools for different crafters! Some stitchers want machine-washable ease (superwash), and others want the more traditional untreated woolly yarn (non-superwash).
Whether you go for tried-and-true Superwash Merino or the old world non-superwash organic line, you're getting beautiful, soft Merino wool carefully hand-dyed in small batches in Pensacola, Florida by a group of makers who truly love what they do! We love knitting and crocheting, and always love seeing what you all are creating with your yarn. When you're ready, find a skein that calls to you:
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