Pineapple leaves, apple skins, cork—the new guard of vegan leather alternatives is varied and entirely fascinating. Leather is a time-honored material, and when purchased vintage, remains a viable wardrobe mainstay. But considering that the water footprint of just one leather tote bag is about 17,128 liters, dreaming up new sources of faux leather is a worthy undertaking. The latest addition to the vegan leather camp? Fabric crafted from coffee pulp waste.

Coffee leather is unique in that it mitigates two areas of pollution and waste: those caused by the leather production and animal agriculture industry, and in the world of coffee fruit, the skins and pulp of which are often discarded post-processing. One Indonesian start-up, the Bell Society, is making it their mission to reuse the materials around them in an effort to combat unnecessary waste. 

The Bell Society and Biomaterials

The Bell Society is the brainchild of former students of the Bandung Institute of Technology in West Java, Indonesia. Its aim? To produce renewable biomaterials. Through research, the founders discovered that, through fermentation, they could transmute coffee pulp into an organic and sustainable material called misel-tex.

As one of the top coffee producers in the world—Indonesia produces 774.6 thousand metric tons of coffee per year, with 48% of the production taking form in coffee pulp waste—the fabric find aligned with the Bell Society’s mission to reuse materials around them. The company has a lab located near a coffee farm, making it easy for them to partner with local farmers and assess waste and use. 

The material was first introduced in 2018, and Bell Society has since partnered with brands like Brodo, Bumi, and Noesa; last year, the material was used in Milan Fashion Week 2021.

“Our goal is to keep innovating, and to find new materials that could be implemented in society,” co-founder Semeru Gita Lestari tells Brightly. “The next step would be scaling and collaborating with designers, the media, and other brands.”

Coffee Pulp vs Traditional Leather

About 200 grams of coffee pulp is needed to produce one square meter of misel-tex. This process takes about a month and a half to complete, with the last two weeks focused solely on treating the material to make it as strong and malleable as traditional leather. 

As with a SCOBY, misel is effectively grown through a fermentation process, with sheets harvested at periods of weeks or months depending on the desired thickness. Once removed, misel is left to dry before treatments begin. The Bell Society relies on classic Indonesian techniques and natural methods of dyeing to avoid unnecessary toxic liquid waste.

The traditional tanning process—which also hinders the ability of animal skins to biodegrade—is a two-part step where the skin is processed into leather. About 90% of leather goods are tanned with the chemicals carcinogenic chromium, formaldehyde, and arsenic to prevent decay. Since the skin has to be soaked in these chemicals there is a lot of liquid waste that goes unused. About 30-40% of chromium is released into waterways negatively impacting the ecosystems and land in which leather production exists. 

The Bell Society isn’t the only group diving into the unlikely relationship between coffee and leather production. In Kenya, scientists have also explored how coffee pulp can be used in the tanning process.

The Takeaway

These vegan materials may not look and feel exactly like the leather you love, but the innovation is truly inspiring.

“We have a vision to make the material that we produce more available for the market, and more affordable with each iteration,” says Lestari. “We’re really looking forward to the future where sustainable material is the norm.”