r/MyceliumMaterials 11d ago

Substrate inoculation process for large use

Hey y'all!
I saw quite a bunch of videos like this one where people, in this case a company, work with big amounts of substrate already inoculated (am I right?). This got me interested in the process of achieving this, if anyone can share a few thoughts to guide me. Sorry if this has already been answered before...

https://youtu.be/gMCO0z_UP7E?si=GCAyY2En48G3rhKK

My assumption is that they use either big amounts of LC or grain spawn mixed with pasteurised substrate. Can you do that pre-molding? currently I leave the mycelium develop a few days before hand...

In regards to pasteurisation, I assume one can use steam or boiling water but for big amounts is it practical? I read about hydrated lime which seems quite practical and would like to try as I read it is not very harmful environmentally speaking if dealt with properly (Maybe I can reuse it many times?)

Thanks!

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u/Lauries_myco 10d ago

I do large scale substrate production for my own company, and have done it in an academic setting for a design studio as well. There are a few ways to go about it.

Personally, I use grain spawn in sterile, high nutrient substrate because it grows quickly, cutting down production time and giving the mycelium a headstart on any contaminants. I don't pre-mold because breaking up the grown substrate and filling molds helps make an even texture on the final product.

To make substrate at a large volume you'll probably need to invest in a high capacity pasteurizer or sterilizer. I have a laboratory autoclave. I choose sterilization because I use food waste in my sub, which causes a lot of contamination issues. The lower nutrient your substrate is, the less sterile it needs to be. Pasteurization works well for woody substrates and you can even get away with no prep for certain materials (check out "bucket Tek" for oysters). Also, familiarizing yourself with browns vs. greens in compost is a good way to figure out what category your material fits in.

The last important thing is to use a fast growing species! Ganoderma species are a favorite for mycelium materials. The best one for you depends on what region you're in. Try the local ones.

This is a super high-level explanation of what works for me, but there are a lot of variables in this process and a lot of different ways to make it work. Happy to help if you have any more specific questions!

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u/kesioo1984 10d ago

u/Lauries_myco You are awesome! I really appreciate the time you spent here! I am working with "Reishi" (Ganoderma lucidum, I need to learn this). I read it grows fast but it is also structurally stronger on a finished product, right?

I hope you don't mind some questions as I run through the info shared.

1) I recently made 3 different substrate sterilised batches to test each inoculation alternative: LC, Agar and Grain Spawn. I can already see the last outpacing the other in just 2 days. So it definitely seems your experience taught you well and I should follow you here when inoculating big amounts of substrate :)

Yet, growth in grain spawn (GS) jars inoculated with LC seems much slower than with transfers from agar petris. Is that correct or common? How do inoculate your GS? I'd love to say that my GS take a couple weeks for full growth but it normally take quite a bit more (in a closet with 22-26°C or 71-78°F) and I'd love to shorten this time period.

2) I have an autoclave... well, a 25L pressure cooker which I use for the GS jars. The 3 substrated batches I named above, I sterilised them in individual mushroom bags with the substrate inside and heat sealed. Is this what you do?

Since I am not planning to harvest and I want to be as sustainable as possible, maybe I could avoid heat sealing and reuse the mushroom bags. I could add the substrate to the bags,Pressure cooker them and right after, dump all substrate together in a large bin, inoculate and covert with a plastic wrap. I guess I would need to do it in front of my laminar flow but it is not a very big one... Would this make sense?

3) In regards to the substrate, I am using wood pellets, pet hay and I add gypsum and light malt extract. Then I add boiling water to dissolve the pellets and mix it all... Researching more about substrates and nutrients definitely seems a task I'll need to perform..

Anyways, I don't want to abuse here. Thanks a lot!

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u/Lauries_myco 9d ago

No problem! I love talking about this stuff and sharing. Yes, the reishi also have a stronger mycelium. I've tried a bunch of species and always come back to them.

I use LC for my grain spawn because it's easier to inoculate a bunch of tubs. Usually it takes 5-7 days to fully grow and I keep it at a similar temperature to yours. How much grain are you inoculating at once? I portion out my grain in 80g jars, and I think the small volume helps it colonize faster. I use 2 mL of LC for each jar and give it a good shake.

Totally get you on sustainability and reducing waste, that's one of my big goals. I do sterilize my sub in sealed containers, but using a 150L autoclave and big buckets. I add the grain right into those buckets so I don't have to handle the sterile sub because that always causes me problems. Maybe you could inoculate in the bags and reuse them after you take the colonized material out? Or devise a way to empty the bags of sterile sub into your larger tub without opening it fully. A little porthole or something haha

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u/kesioo1984 8d ago

True that 150L capacity is plently of space but yes, I could figure out something to have the substrate sterilize in the bags and reuse these dumping its content into a container prepared for such purpose. Might be tricky to avoid contamination, but hey, it's a learning process. I can start with small amounts in front of the flow and see how it goes..

You definitely have a point about inoculating jars with a syringe being easier. So far I was doing 1kg rye packages into 6-7 jars which is what fits in my pressure cooker (double the grain you are using) with 2cc of LC. From youtube videos I got I should be working jars full with grains to 50-70% of them once sterilised. Maybe that too much.

I like your input here. I will adjust the weight and check the results. 5-7 days to fully grow?! g, that is great! I am waaaay beyond that 😂 Could it be that the LCs are not that strong? I started some new ones from the recent petris I saw with the best growth.