From my earlier forays into the world of applied mycology I know the artifacts of a kitchen sink mushroom grower all too well. Petri dishes, scalpel, syringes, needles and injection ports do no longer make me stop in awe. I wield them well enough to make the mushrooms fruit within a couple of weeks.
There is a story to why I had to newly buy all of the necessary lab equipment to rebuild my mycology lab from ground up. I will tell it in the end of this post.
One thing I had not had the guts to attempt so far was the production of a black coloured growth medium for the petri dishes. I had researched how the scientific community does it as well as read some posts by DIY psilocybe growers on pertient forums. However, the mention of activated charcoal and the discussion by some scientists of how it could inhibit growth of some of their researched bacteria, worms or fungi was unsettling to me. So I pushed the idea aside back then. Now I had found new vigour in my mycologic enterprises and looked up a recipe for black coloured agar medium to grow mycelia in petri dishes.
The recipe I found looks as follows:
Lab-grade malt extract agar with charcoal (MEA-C), sufficient for 1 litre final volume of medium.
Add to ~800 mL distilled water. Stir to mix. Bring to final volume of 1000 mL. We recommend autoclaving then allowing to cool to the point where containers of the solution are warm, but cool enough to be handled safely. Swirl containers to ensure contents are well-mixed, and then pour/dispense by pipette into Petri plates or other containers in your flow hood or glove box. ~50 plates at ~20 ml/plate. This medium is black to increase visibility of light-coloured mycelia.
I ordered up most of the powdered ingredients needed from a couple of online stores. Agar, malt extract and dextrose were reasonably easy to find. Apparently it's used in kitchens and bakeries. So I found a supplier for culinary professionals, that provides all of the powders except peptone. It was unfortunate that the .ch web store shipped from a warehouse in Germany, but the convenience of ordering 85% of the ingredients in one place, in food grade, bulk quantities trumped the fact.
The activated charcoal powder was a bitch to source, too. Apparently it is used in beauty applications for bleaching teeth and such. However, it mostly is offered in shredds, not powdered. I imagined the mess caused by a laminar flow hood pumping out several cubic liters of air across my mortar and pestle grinding the stuff to powder. The mental image of black, smearing powder covering my lab encouraged me to source the stuff in powedered format. The 500 grams pack I found on a beauty suppliers web store looked of decent quality and was made from 100% coconut husks. Seemed sustainable and high quality enough for my application. See links below for the sources I used.
Today the last of my orders arrived. All looks good, I can't wait for the lab hardware order to arrive, then I can get started pouring plates and start inoculating my first few colonies.
Aktivkohle-Pulver aus Kokosnussschalen, 500g