The shoe that grew in the dark
In a vertical farming facility in the Netherlands, trays of sawdust sit in climate-controlled darkness. Technicians adjust the moisture, the airflow, the temperature. And then they wait. In less than two weeks, a dense, foamy mat of interlocked fungal threads has spread across each tray — a material that can be sliced, pressed, tanned, and dyed until it looks, feels, and drapes like cowhide. On April 15, 2021, Adidas laced this material into a pair of Stan Smiths and announced that the shoe’s upper had been grown, not manufactured.
The material was called Mylo, and it came from a San Francisco biotech company called Bolt Threads. Dan Widmaier, David Breslauer, and Ethan Mirsky co-founded the company in 2009 out of a single bench in an incubator, working on the problem of replacing the textile industry’s worst feedstocks. Their first product was Microsilk™, a fiber synthesized from spider-silk protein by genetically engineered yeast. Mylo came next: made from mycelium, the dense thread-network that runs beneath any mushroom cap, grown on agricultural waste and finished with what the company calls green chemistry. Bolt Threads licensed the original growing technology from a New York startup called Ecovative, then spent years on the finishing steps that turned raw fungal mat into something a tannery would recognize.
The first object made from Mylo had been a handbag, not a shoe. In 2018, Stella McCartney built a prototype of her signature Falabella bag from the material and showed it at the Victoria and Albert Museum’s Fashioned from Nature exhibition in London — no price, no production run, but enough to plant Mylo in the luxury imagination. By October 2020, Adidas, Stella McCartney, Lululemon, and the French conglomerate Kering had formed a formal Mylo Consortium, pooling investment to bring the material to commercial scale.
Adidas chose the Stan Smith for reasons that were half practical, half pointed. The shoe’s clean white upper, essentially unchanged since the early 1970s, was the simplest possible canvas — nothing to distract from the material beneath it. Mylo covered the outer upper, the perforated three stripes, the heel tab overlay, and the branding badge. Natural rubber handled the midsole. Martin Love, Adidas’s category director for the project, said it had taken the team a full year just to get from receivable material to wearable shoe. Leftover mycelium waste went to compost.
The case for Mylo was that bovine leather carries a significant carbon load while synthetic alternatives typically trade dead cows for petroleum plastics. A material grown in days on agricultural byproduct, biodegradable at end of life, and — as Bolt Threads’ VP of product development Jamie Bainbridge noted — capable of being blended in ways that cowhide never could be: that was the pitch. The Stan Smith Mylo was explicitly a proof of concept; Adidas committed to a commercial release within twelve months.
How quickly the material scales is still being decided, as it tends to be with young biomaterials meeting old supply chains. But footwear has always been a materials story — bark, papyrus, cowhide, rubber, nylon, carbon-fiber plate. The question in each era is what humans find lying around and what they are willing to do with it. Sometimes, apparently, the answer is to leave it in the dark and see what grows.
Sources
- Adidas — Stan Smith Mylo press release — April 15, 2021 announcement, shoe construction details, Mylo Consortium membership
- Engadget — Adidas Stan Smith Mylo — Netherlands growing facility, Martin Love and Jamie Bainbridge quotes, Bolt Threads founding history
- FashionUnited — Stan Smith Mylo — industry context, V&A Falabella prototype, commercial timeline