Cultivation tests on spent coffee grounds

Around end of last year I have collected for some days the spent coffee grounds from my workplace. I sterilized it in pressure cooker in glass jars and then inoculated it with spawn either bought from Mushroombox.co.uk or what I collected in the wild.

I have read a lot about recycling coffee in this way, but I wanted to see with my own eyes.

I have tried several species, mainly oysters: Pleurotus citrinopileatus (yellow oyster), Pleurotus ostreatus (grey oyster), Pleurotus eryngii (King oyster), Lentinula edodes (shiitake), Hypsizygus ulmarius (elm mushroom), Pleurotus djamor (pink oyster), Hericium erinaceus (lion's mane). With the latter two I had no success, but I will give it another try later on.

All the rest managed to form pinheads (small pre-shrooms) and they mostly developed to elongated fruit bodies. The elongation was due to the fact that the basic setup I used was not meant to control levels of O2 and CO2 and to provide regular fresh air exchange, all crucial at time of fruit body development.
After the moving is complete back to Hungary I hope to renew the experiments on more species and with a better suited setup.

Spawn run (while the shroom conquers the substrate) took something between 30-60 days, which is pretty long for so little quantity, but they were basically forgotten there in the dark of my shelves on room temperature and without any additional substrate material, coffe grounds are pretty dense to be simply overrun.

After this incubation period the jars looked like this:

I opened them up and placed into nursery boxes with a simple humidity and temperature meter:

 The boxes were covered, and the top opening was covered with a garden foil:

I tried to keep the humidty above 85-90%, by keeping the bottom of the box constantly moist and removed the cover for air exchange in the mornings and in the evenings. These were all but sufficient for the proper mushroom formation, but at least I got some results.

The grey and yellow oyster and the shiitake did well on the substrate:

Pleurotus ostreatus

Pleurotus ostreatus

Lentinula edodes

Pleurotus citrinopileatus

The P. eryngii took its time compared to the others: until the king oyster decided to form some shy fruit bodies, the yellow oyster gave 3 waves of crop...

Pleurotus eryngii

 My wild collection of Pleurotus was extremely desorientated. No matter what I did, it kept forming these impossible shaped fruit bodies. I think it really missed the fresh air movement that it got used to in nature:

wild Pleurotus strain

I am not very familiar with the elm mushroom. It formed plenty of pins, out of which only some developed into bigger fruit bodies, strongly elongated and deformed:

Hypsizygus ulmarius

 I made some checks after disposal of the test glasses. I found that run within the substrate was only partial in most cases, as visible on the photos below:

It is mostly due to the density of the coffee. Most larger scale projects mix at least wood shavings to the coffee, I might give it a try next time.