The Zero Waste Coffee Project

Imitation leather made from coffee pulp. Bell Society, Indonesia.

In Indonesia, the world's fourth largest coffee producer, the by-products from coffee processing are barely used, transformed or upscaled into new products. Some young people in Bandung, West Java, want to change this.

When Arka Irfani and Hisyam Bin Ahmad H.M, two of the Founders of the Bell Society, were still biology students at the Bandung Institute of Technology, they had an idea. While studying the results of certain experiments in the campus lab where they processed fermented food for a course assignment, they discovered the existence of "cellulose sheets" formed in the fermentation process of fruits. Initially, they made paper from these cellulose sheets and tried to sell it. But it turned out to be not worth the cost as there was not much of a market for this kind of paper. Then they started thinking about other applications for these cellulose sheets.

The Bell Society Team: Hisyam (left) Arka (right)

They came up with the idea to turn misel, as they called their microbial cellulose sheets, into alternative or imitation leather which could be used to make jackets, shoes, wallets, bags, and so on. After testing various kinds of raw materials such as waste from tomatoes, pineapples, mangoes and others, they accidentally saw a pile of coffee pulp at a coffee cooperative in Lembang (Bandung, West Java). They took some of the coffee pulp home and began conducting experiments.

They fermented the coffee cherry skin for about one month by adding bacteria so that they can grow cellulose sheets  (misel). And it worked! From about 200 grams of coffee pulp they produced roughly one square meter of misel (90 x 90 cm, 0.5 - 1mm thick).

Misel, in process

Arka Irfani and Hisyam Bin Ahmad H.M and their growing team are now partnering with the Gunung Tilu coffee cooperative in West Java. At the moment, they process approximately one tonne of wet coffee pulp per year, which results in 5,000 sheets. The fermentation and following drying is still done at the Bell Society`s lab, but Arkan and Hisyam hope to establish a processing site at the coffee cooperative to be more efficient. Their plan is to share the profit of sold misel sheets with the co-op.

The Gunung Tilu coffee cooperative admits that they are very happy with Bell Society's initiative since the pulp will usually just pile up, often for years. In addition to that they have an extra income, although it is currently not too high (IDR 2,000,000,-/$US140,- per 1 ton of coffee pulp). But they hope that the demand from Bell Society clients for misel will increase, and maybe even increase the value of coffee pulp.

Misel, dried

Arka and Hisyam told me that they carried out in-depth research over the past four years to develop an excellent quality misel. Their main goals were to find a good leather consistency, starting from the desired colour, making it waterproof, and removing any poor odours, to create a product that is not easily torn or damaged. They are now satisfied with the quality of their "vegan" or imitation leather, which is smooth and has a natural colour that is not too flashy.

Their hard work paid off when they finally conducted quality tests at the Balai Besar Tekstil (Textile Institution Center). The results were astonishingly successful when compared to the quality of genuine animal leather. Some of their scores are as follows:

∙ For the tensile test, their score is 13.25 Mpa whereas animal skin is around 8-17 Mpa; some

  synthetic leathers are even below their quality

∙ For the elongation test they reach 21% while for animal skins it is around 20 – 30%.

∙ For the tear test, they have a score of 60 microns and this is the same as the tear test of most fabrics.

Besides it´s overall high quality, misel has to offer some key advantages over animal leather. Firstly, the substitution of animal leather with a plant-based imitation leather made from agricultural residues reduces carbon emissions significantly. This is not a surprise if you look at CO2 footprint of the entire leather production chain.* Secondly, the substitution of imitation leather with plastic coatings. Thirdly, there are no toxic residues in the processing of plant based leathers like misel. All these are reasons why a company like Bell Society can and will contribute to an eco-friendly and sustainable textile and apparel industry. And this is even more the case as the company only works with pesticide free coffee pulp.

The quality of Bell Society’s misel has improved a lot since they first introduced their product in 2018. This gave the young team the confidence they needed to scale up the commercialization in 2021. They sell a misel sheet (90x90 cm) for IDR 450,000,- which is about USD $32,-, and claim to have achieved their BEP (Break Event Point) last year.

Bell Society created a campaign called “Cakra Donya” that unites many brands in Indonesia such as UMA Interior Design, Brodo shoes, Bumi shoes, Noesa, Pijak Bumi, Bluesville clothing, Revolt industry fashion accessory etc., who are all interested in using misel for their products, and partially use it already. Some of these products even made it last year to the "Milan Fashion Week 2021".

Products made with misel

Arka and Hisyam admit that there is currently one head-to-head competitor in Indonesia, namely Mycotech Lab, which is also located in Bandung, West Java. Mycotech Lab developed a similar imitation leather as Bell Society, but instead of bacteria they use mycelium. Their brand is called MYCL.**

The Bell Society's grand vision is to become the world's #1 provider of affordable biomaterials for everyone. Its mission is to encourage people to start using sustainable materials so that an environmentally friendly ecosystem can be created. "In the future, we want to process more biomaterials from waste so that they can be processed into various things that have greater value," said Arka, who is currently investigating with his team the use of coffee silverskin, the by-product of coffee roasting, in a next-step technology for the production of shoe soles.

“This year", he said, "we will launch many interesting programs besides our CAKRA DONYA campaign. And by the middle of the year we plan to collaborate with many parties around the world to support our campaign on!”

* Leather Carbon Footprint, Review of the European Standard EN 16887:2017

** A couple of years ago I supplied Mycotech Lab with spent coffee grounds from our coffee shop, at a time when they still were in the testing phase. Unfortunately they decided not to continue with spent coffee ground as part of their substrate for the mycelium.

If you or your company are interested in collaborating with Bell Society, please contact them directly at: and

WhatsApp: +62 851-5515-1221 (Hisyam)

More information about the Bell Society can be found here:




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