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Posted on Tue 3 Mar 2020

Materials research

Experiments with oyster mushroom mycelium and SCOBY leather = smelly studio

A film by

Posted by

Robbie Thomson

Robbie Thomson

Robbie Thomson is a Glasgow based artist working between the fields of visual art, music and theatre. He joined Pervasive Media Studio on the Watershed/MAYK 2020 Winter Residency programme.


A film by

Other Animals

A series of public interventions which use soft robotic sculptures to raise awareness of local ecological issues and the wider climate crisis.

I've researching biological materials to use for making sculpture and robot parts, the idea is to use these organic materials in the construction of synthetic interactive organisms which will be installed in public places.

So far my experiments have been with Kombucha SCOBY leather and Oyster Mushroom mycelium, I want to use the leather to create bags, sacks and skins and the dried mycelium will be used for structural parts and bones of the robots.

The results have admittedly been a bit hit and miss so far... there's definitely room for refinement in the process so will hopefully get more consistent results for round 2.

Sarter materials:

oyster grain spawn

Grey Oyster Mushroom Grain Spawn (kindly given to my by Andrew Adamatzky at the Unconventional Computing Laboratory, UWE - )

kombucha SCOBY

A Kombucha SCOBY (symbiotic culture of bacteria and yeast)

shiitake bag

A bag of Shiitake Mushrooms that were already fruiting which was given to me by my pal Dav.

kombucha prep

Preparing the sweet tea which the SCOBYs will colonise.

kombucha prep

The SCOBYs will feast on the caffeine and sugar content of the tea, these trays were sterilized and covered to (hopefully) stop contamination.


I decided to use coffee grounds as a substrate for the mycelium, these had been collected from a coffee shop the same day - the idea is that they are already pasturised by the espresso machine. They could also be easily shaped and moulded.

At the same time, another batch was prepared using pasturised Rye Grain as the substrate.

coffee innoculation

Inoculating the coffee grounds (big thanks to Tom Marshallsay who knows his stuff when it comes to mushrooms)

shiitake growth

Shiitake had a couple of big flushes.

shiitake mushrooms


It was all going so well,

....and then came the dreaded mould


First signs on Shiitake.

coffee mycelium

Maybe myceliuym, maybe something more sinister, the coffee was slow to colonise so I took some aside and experimented with better air exchange.

kombucha mould 3

Kombucha started to get some nasty blotches (at least it's not for drinking).

kombucha mould 2

The SCOBY was slower to form in the metal trays - these 'mothers' were from another source so I'm unsure if it was just the potency of the colony or if the environment was a factor. Lots of nasty mould here.

coffee mould

Coffee grounds not looking good.

There were some good outcomes though:

kombucha mould 1

Final growth stage of the big SCOBY before I harvested it... actually grew to a decent thickness, there are clearly mould patches on top but also has discolouration attributed to trapped yeast deposits. The temperature is definitely a big factor here, the room that I was using has a fluctuating ambient temperature of 10 to 20 degrees (but usually closer to 10).


Wet SCOBY after harvest - pure John Carpenter.

SCOBY drying

Drying the skin - the mould has left some quite interesting patternation, I'm going to experiment with drying techniques, fusing the skin, waxing and dying. Good air exchange will be critical here I think. The sheet is strong although not of a uniform thickness, if I hadn't been creating such a biohzard then I would perhaps have let this thicken further.

shiitake mycelium dried

Dried Shiitake 'brick' - has similar consistency to wood though perhaps a bit fragile. I'm going to attempt to cut and carve this sample, looking at ways to dry and harden further.

Oyster mushroom rye grain

The pasturised Rye Grain worked very well and has a really strong mycelium growing. The vacuum bag was also pasturised within the pressure cooker which has kept things sterile but also allowed good air exchange, will look at using this method for the next batch.