From small samples to wear and wash tests: How Spiber met Untouched World’s high bar

It’s pouring rain when I visit the Untouched World offices, which doubles (quadruples?) as a shop, cafe, and factory. You can watch employees working on the production floor through a window in the shop. I’m intentionally early for the meeting with Development Manager Fiona Bretherton and Head of Marketing Esme Chiverton so I can look around the space and touch the clothing.

Untouched World is a New Zealand clothing brand most known for their merino knits. Sustainability has been a founding core value since their launch in the 1990s. The company’s Spring/Summer 2025 collection includes a number of tops made with a blend of cotton and Spiber’s Brewed Protein™. From a warm striped sweater to a beautifully draped and pleated sleeveless shirt that comes in the kind of elegant cream that I know I would stain immediately. The feel of these tops is soft, a texture I’m familiar with from cotton blends that include polyester or other plastics. But these are plastic free — made with Spiber’s fermented yarn.

The tag includes an explanation of how Brewed Protein is made and there’s even a jar of Brewed Protein on display to touch. It’s silky smooth and despite working as a journalist in this space, I struggle to imagine how this cozy yarn came from yeast. The jar fits right in with Untouched World’s transparent approach to materials. Next to a sofa by the changing rooms is a touchable sample box with wool at different stages, straight from the sheep all the way to processed merino yarn.

“Having the fiber there was really important for us in each of our stores, so people can actually touch and feel the Brewed Protein fiber,” Fiona tells me. “You might not be familiar with where it came from, but you can understand it as a fiber.”

Invested from starting source to end of life

Fiona has worked at Untouched World for 17 years and now heads up sustainability in fabric and fabric innovation. She’s passionate about textiles from natural sources with good end of life options. Over the last few years, she’s requested dozens of samples of various biomaterials, but none hit the mark until Spiber.

“I do a lot of reading and seeing what’s out there. There’s a lot of exciting fabric innovation happening but sometimes they’re still figuring things out — maybe it’s only 30% plant-based materials or it’s recycled but half is still fossil fuel based. We’re not looking at partial solutions.”

Spiber popped up during research into spider silk and an email conversation started back in 2023. First there were questions about what it’s made from and its end of life, then swatches of fabric and yarn were being shipped across the ocean.

“We are pleased to collaborate with Untouched World, a brand that shares our commitment to responsible innovation and long-term sustainability in fashion. Seeing our Brewed Protein™ fiber and technology applied in their collections represents an important step in expanding the possibilities of material choices in the industry,” Spiber’s Marketing & Communication Division wrote in a statement to BioRunway.

“Untouched World’s thoughtful design approach and deep respect for nature strongly resonate with our vision of creating materials that support a more sustainable relationship between people, products, and the planet. Through this collaboration, we hope to help shape a future where high-performance garments contribute to the expansion of biomaterials.”

Looking for longevity: Organizational effort and individual testing

With the Brewed Protein yarn samples, Untouched World created their own swatches of various wool or cotton combinations, then produced four sample garments from different blends. These were wear tested by the product development team. Comfort, wear, and washability are all crucial factors in deciding whether the fermented yarn holds up to their quality standards.

“We're in a really unique position because of our size. We're big enough to take on these R&D projects but we're small enough to be nimble,” Fiona says. “It does cost resources and money, but that's something we're willing to do because it's a priority for us.”

Their size also means they can work with smaller samples than a bigger brand might need, making them a good partner for companies that are still scaling.

In the end, they settled on a 90% cotton, 10% Brewed Protein blend. The bioyarn offers advantages that a 100% cotton garment can’t, including being softer and more supple, warmer, and holding its shape better than cotton alone.

Other companies are getting some of these traits by using a polyester blend. Untouched World’s product line is 93% natural fibers and they’re working to reduce petroleum-based products across the board. Socks and leggings are some of the holdouts — it’s hard to get a durable stretch without some nylon.

The company prizes longevity. At their recent 30th birthday celebration, they encouraged people to show them their oldest Untouched World items. A new university student showed up in a sweater he’d snagged from his dad’s closet — the 90s original looked brand new.

That wearability and repairability is crucial to Untouched World’s brand — it’s why none of the 20 plus other biomaterials they tested were considered ready.

High-trust customers don’t need in-depth explanations

It is a long road that ends in the biomaterial blend sweater that Fiona just happens to wear for our interview.

“It really is my go-to sweater at the moment,” she says. “And our customers have loved it. It’s one of the top-selling products — people are certainly open to it.”

I’m curious about how much information Untouched World felt they had to give their customers. “Brewed Protein” isn’t an intuitive description and most people aren’t familiar with fermentation beyond beer. Their website describes it as “made using sugarcane and a fermentation process (think brewing kombucha, but for fabric).”

“We've come from a privileged place of having a lot of brand trust. Our customers are really open to something new,” Untouched World Head of Marketing Esme Chiverton tells me. “We just need to let them know the benefits and show them that it can slot into a beautiful collection without standing out. You've already got them hooked with a stunning garment, then you remind them of those awesome features.”

Whether or not their customers could explain what Brewed Protein is hasn’t held them back from embracing the novel material.

“The garments developed through this collaboration, made from a blend of organic cotton and Brewed Protein™ fiber, have also received highly positive customer feedback,” Spiber’s Marketing & Communication Division adds. “Customers describe the material as exceptionally gentle on the skin, as well as light, soft, and warm, making the garments easy and comfortable to wear, including for those with sensitive skin.”

Fiona hopes Brewed Protein is just the beginning, and that other brands will follow suit. She’s posted on LinkedIn about looking for nylon alternatives and while no solutions have come up yet, there’s a clear desire from a lot of companies to reduce petroleum-based textile use.

“There is an interesting space right now around brands that are willing to take on the next step of the R&D for the startup, and to partner with them,” Fiona says. “We can even send swatches back to the innovative fiber company, which helps them with their R&D as they're trying to scale, as well.”

“I think that's how we're going to solve some of our biggest problems in the textile industry. Not by developing something alone and holding it close, but by sharing and collaborating.”