By Published: May 4, 2023

Italian fashion icon Giorgio Armani has his suits. German designer Karl Lagerfeld touted the “little black dress.” CU Boulder researcher Fiona Bell, however, prefers clothing made with the help of a warm glass of kombucha—the slightly-sour beverage brewed by fermenting tea with sugar. 

Right now, the researcher is touring the Living Matter Lab at CU Boulder’s ATLAS Institute. Tucked into corners and under tables in the lab are mason jars and plastic storage containers filled with brown slurries. They smell like vinegar and have a thin layer of slimy, almost skin-like material growing on top. Brewers call this film a symbiotic culture of bacteria and yeast (SCOBY), or “the mother.”

Bell, who earned her doctorate in creative technology and design from CU Boulder this spring, does research in the field of biodesign, which sits at the intersection of biology, food science, materials engineering and more. 

In this case, she and her colleagues are growing their kombucha for haute couture fashion

The researchers harvest and dry the SCOBY to make a material called “kombucha leather,” a process that can take weeks from start to finish. To show what it can do, they crafted a “breastplate” shirt. The garment looks like something Spartacus might have worn in ancient Rome.

“It’s definitely different,” Bell said. “But I think there’s an inherent beauty to this breastplate.”

It also comes with a series of embedded LED lights that flick on every time you give the wearer a hug. The group described its experiments in February at the Seventeenth International Conference on Tangible, Embedded, and Embodied Interaction in Warsaw, Poland.

Bell noted that kombucha chic might not be everyone’s cup of tea. But she sees the project as an antidote to “fast fashion,” the modern embrace of clothing that can be produced quickly and on the cheap, and just as easily thrown away. 

Her work is fashion at the pace of bacteria and yeast.

“It’s slow fashion,” she said. “It taught me to let go because it was a living thing. Sometimes, imperfections would form in the leather like bubbles or dark spots where clusters of yeast would gather. I had to accept that it was the organism bringing its own voice into the design.”

Person holds up plate with slimy kombucha SCOBY

Kombucha SCOBY seen before drying. (Credit: Hunter Allen-Bonney)

Turning microbes into fashion

Bell didn’t set out to be a fashion designer. She’s a mechanical engineer by training, and the closest she came to making clothing was knitting scarfs. 

As an undergrad at Santa Clara University in California, however, she learned how to brew her own kombucha (a hobby her former roommates hated because it made the apartment smell). It was her advisor at CU Boulder, Mirela Alistar, an assistant professor who leads the Living Matter Lab, who tipped her off to all kombucha could do.

“She said, ‘you know, you can make stuff with the SCOBY,’” Bell said. “My mind was blown. Up until that point I had thought it was just a waste product of the fermentation process.”

Fiona Bell and Mirela Alistar

Fiona Bell, left, and Mirela Alistar, right. (Credit: Hunter Allen-Bonney)

The team isn’t the first to make clothes out of kombucha leather. Designer Suzanne Lee debuted a line of “BioCouture” bomber jackets, which she crafted using similar materials. For more than $2,000, you can even buy a Stella McCartney Frayme Mylo shoulder bag, a faux-leather accessory made from mycelium, the root-like structures of many fungi.

Bell explained that as kombucha ferments, the microbes inside naturally produce the SCOBY, a gooey layer that’s rich in cellulose. If you scoop out that slime and treat it with olive or coconut oil, the SCOBY will dry into a sheet that’s less than a millimeter thick but surprisingly hardy. It looks and feels a lot like animal leather.

In all, it took Bell and her colleagues over three months to make their kombucha leather breastplate, laying it down strip by strip.

“I learned that I have to slow down to the pace of the organism,” Bell said. “I have to wait for four weeks for a layer to grow, and once I have a layer, I need to know exactly how I’m going to use it.”

Thinking slow

The team also gave their seemingly ancient breastplate a modern twist: The researchers coated one of their layers of SCOBY in activated charcoal, a biodegradable substance that can register and carry faint electrical signals like a metal conductor. Touch that part of the breastplate with your bare skin, and a series of LED lights embedded in the material will glow to life.  

“If you brush up against the breast plate briefly, the LEDs will give off a dim little spark,” Bell said. “But if you give someone a big, tight hug, they get really bright and their glow lingers.”

And, unlike a tank top from H&M, the shirt’s material will degrade in soil in about a month. (You can also easily remove and reuse all of the electronics, Bell said). 

The engineer and designer hopes the project will help people reimagine their relationship with clothing. You never know what you can discover, in other words, if you only slow down.

“One of the coolest things about kombucha is its accessibility,” Bell said. “Anyone can brew their own kombucha. You can grow your own wallet in a month.”