Mushroom Culture Step 2

Shiitake mycelium in a culture
jar, cloned from a mushroom.

Our Mushroom-growing experiment progresses well, if a little slower than expected. In the first step we cloned some Shiitake cells into several Malt-nutrified agar vessels. Not unexpectedly, given the crude nature of our lab setup, some of those became infected with other, unwanted organisms and had to be tossed out. There remained two jars of clean, healthy mycelium - the "root" structure of fungi. The next stage in growing Mushrooms is to bulk these up into much larger volumes.

This is their story.

The cloned mycelia grew a little more slowly than I expected. I think that the relatively cool Winter temperatures are lower than these fungi really like. I anticipated that they would fill their Agar dishes within 2 or 3 weeks. Instead it took 6. The only bad thing about that is it means that "bad" infections stand a greater chance of slipping into the culture jars.

Our aim is to increase the volume of the mycelial mass so that, when it comes time to actually start Mushroom production, we have plenty of starter material. This will give the Shiitake fungi the best possible chance of out-competing other, more noxious, "weed" fungi and bacteria that are always floating around in the air. It's just like food gardening, really. We coddle the little darlings we are trying to encourage by giving them favourable growing conditions, and by weeding out possible competitors.

As part of the experiment I chose two different growth substrates for expanding the mycelia: spent brewing grains and White Sorghum.

Spent brewing grains are an obvious choice for me. Every week or two I produce several kilo's of malt-bran from which I've extracted much of the starch (and converted it into brewing sugars along the way.) But that still leaves me with a hell of a quantity of "waste" bran containing quite a bit of leftover starches and sugars. I feed quite a lot of it to the Chickens who seem to thrive on it, but by the 3rd day the whole wet, sticky mass is turning sour, and I don't want to chance feeding such a wild potage to the Chooks. Besides, by that point they're probably thinking, "Oh No! Not that stuff for supper again!" Turning it over to mushroom growing seems to me an obvious thing to try.

The choice of White Sorghum is the result of one of those happy accidents. I had a couple of bags of Sorghum in storage, awaiting planting. The one bag must have had a hole in it, because I discovered it to be filled with an evil-smelling fungal mass that had to be turfed onto the compost. Evidently fungi really like Sorghum.

To create Mycelium Growing Jars, I filled some old pickle jars with the growing media – two jars containing brewing grains, and one with Sorghum. With the lids placed loosely on top of the jars, I sterilised them in the pressure cooker for an hour. The pressure cooker volume is the limiting factor. It can only cope with 3 jars at a time.

Once the jars had cooled, I sanitised my "lab" area and got to work. Removing a chunk of the mycelium from the culture jar, I stuck it into one of the growing jars, replaced the lid, and shook it all up to break up and distribute the mycelial threads into the growing media.

Then things went quite quiet for a couple of weeks while nothing seemed to be happening.

Suddenly, one morning, I noticed whispy white thread on the side of one of the jars.

The Mycelium is running!

Another couple of weeks went by as the mycelia slowly spread through their growing media. As I write this, one of the jars containing brewing grains seems to have become infected. I removed it to far away from anything else, and, although some noxious alien growth is evident, it seems that the Shiitake mycelium is beating it out, encapsulating and hopefully out-growing the alien. The other brewing-grain jar is filled with beautiful, white mycelium, and is ready for expanding up yet another step. The Sorghum jar mycelium is growing much more slowly, but there is clearly a solid mycelial mass in the middle of the Sorghum grains. Needs to be left alone a while longer.

In the meantime I have inoculated another 3 growing jars, this time avoiding the original lids in favour of foil caps. I don't trust the hygiene of the lids or their efficacy in keeping lurgies out.

Although the brewing grains seem to be a very favourable growing medium (at least for Shiitake!) I suspect that the looser particles of the Sorghum growing medium will actually be easier to use in Step Three – Expanding the Mycelial Mass by another 10-to-1 step.

Await ye here, and I shall report back!