Kombucha Leather Material

a detailed open source project by Riina Oun, Images by Maria Pincikova & Riina Oun

Riina Oun undertook a 3-month material research residency at the lab, focusing on kombucha SCOBY (symbiotic colony of bacteria and yeast) and it’s possibility to be used as sustainable leather-like vegan material. SCOBY is the bacteria that grows on the top of kombucha (a drink).

The research started with Riina growing her own kombucha SCOBY in large containers in the lab. She found that the best results were achieved when the samples were left to grow over a long period of time.

GROWING THE MATERIAL:

Ingredients:

  • 1l filtered water
  • 2 tea bags
  • 70g sugar
  • 20ml kombucha starter liquid

Method:

  • Make tea using the filtered water, add the sugar and let it dissolve
  • Let the tea cool down to below 30c, then mix in the kombucha starter liquid
  • Pour into a container, cover it with breathable fabric and leave it to ferment in a room with a temperature above 20c
  • By day 4 the SCOBY (symbiotic colony of bacteria and yeast) should start to form on the surface. Leave it to grow for 14 days or longer

Growing kombucha
Fig 1. Growing Kombucha SCOBY

Dried Kombucha SCOBY
Fig 2. Dried Kombucha SCOBY

DYING THE MATERIAL:

Riina pushed this research by further manipulating the material once grown by introducing dying techniques.

Dying with Metal:
Dying the SCOBY with various metals via corrosion –mild steel proved to be most beneficial for this purpose. However, when left for too long, the corrosion tends to weaken the bonds of the material making it more fragile.

Dying SCOBY with metal
Fig 3. Dying SCOBY with metal via corrosion

Dying with food colourants and natural pigments:
More successful dying techniques were to add colour using food colourants as well as natural pigments.

SCOBY colour samples
Fig 4. SCOBY colour samples

After achieving the best results she could by just growing the SCOBY Riina decided to spend the second half of her research residency to experiment with making a composite material.

By blending the SCOBY and combining it with various ingredients Riina managed to improve it’s durability and create a relatively strong, hard wearing and interesting bio material. By interchanging some of the ingredients the aim was to engineer the optimal material, suitable for production of small “leather” accessories.
This process also enabled dye pigments to be added at different stages to achieve the strongest and most uniform outcome.

Material Lab & equipment
Fig 5. Material Lab & Equipment

To achieve this Riina needed access to a lot of Kombucha SCOBY and collaborated with Momo Kombucha – a London based brewery who were able to supply SCOBYs on a regular basis. This also meant that Momo could now supply there SCOBY as a by-product of there kombucha production which had previously been composted.

Momo Kombucha
Fig 6. Momo Kombucha SCOBY

KOMBUCHA SCOBY VEG. GELATIN CHARCOAL COMPOSITE RECIPE

Ingredients:

  • 500g SCOBY
  • 300ml water
  • 20ml glycerol
  • 3g charcoal
  • 6.5g veg.gelatin

Method:

  • Blend the SCOBY in 100ml water using a hand blender
  • Mix 20ml water, 20ml glycerol and 3g charcoal powder together and Add the mixture to the SCOBY blend and mix.
  • Dissolve 6.5g veg.gelatin in 50ml cold water and add to 100ml boiling water mixing vigorously.
  • Mix everything together thoroughly.
  • Pour onto a baking tray and leave to air dry.

SCOBY veg. gelatin sample
Fig 7. SCOBY veg.gelatin composite

EXPERIMENTS WITH DIGITAL FABRICATION

Digital fabrication experiments revealed that laser etching turns the SCOBY composite material white, unlike laser etching leather or wood, for example, when the material burns black.

Whilst the material research is an ongoing work in progress, Riina has developed a biodegradable coaster to highlight the results to date. By adding a layer of shellac (a natural resin secreted by the lac bug) she has managed to make the coasters water resistant.

Laser Cut & etched coasters
Fig 8. Laser cut and etched SCOBY coasters

Riina has also successfully produced the first prototype of a fully sustainable Riina O Aura glove – made of kombucha SCOBY composite material.

Riina O Aura Glove
Fig 9. Riina O SCOBY Aura Glove

To find out more and follow Riina’s continuing research head to her website:

www.riinao.com