Sterilizing 95 Hardwood Substrate Production Blocks for Mushroom Cultivation
All right, so we finished making up our substrate. Now it's time to sterilize everything, so we'll wheel our sterilizers out and start loading up our loading these up with our blocks. So yeah, I have these things on wheels, and it makes it really easy to move them around. So yeah, we have three of these atmospheric steam sterilizers, so when we're running all of them at the same time, we can sterilize about eighteen sixteen eighteen hundred pounds of raw substrate at once. So it really helps with our bulk substrate production and keep us flowing.
So yeah, we have our sterilizers. If you wanted to get a peek in there, we just have a heating element with some water and then a float valve. It hooks up to our water connection and automatically refills is what with water as needed. We basically just put all of our blocks in here. This one can fit 63 bags per per unit, so get quite a bit of substrate in each one, 600 pounds of substrate per drum.
We'll just load them in there with kind of like a little pattern, placing each block over the holes so the steam can penetrate efficiently. You can sterilize a few different ways. One is pressure steam sterilizing. So this is an atmospheric steam sterilizer. We'll just load the substrate in here, and it's hooked up to a PID controller, so this will monitor our temperature as well as the time.
So this will cook for, depending on the recipe, 12 to 14 hours, after which this will automatically shut off this the heating element, and it'll start cool down. I'll let it cool for about two days. Then that at that point we can load it unload it into our laboratory, allow it to cool further, then inoculate it with a fresh mushroom mycelium, inoculation being placing a fresh grown out mushroom culture, whether it be grain spawn or whatnot, in do our sterilized bags for colonization. So that's about it for for this system. We were using the pressure steam sterilization All-American pressure cookers for quite a while.
This just allows us to do a lot more substrate at once. So this is our All-American forty one and a half quart pressure steam sterilizer. This is a really heavy-duty piece of equipment. Works great. So this is really useful for an at-home cultivator.
So we have a nice chamber that we can load our substrate in, and I also use these electrical box boxes. Place those at the bottom of our sterilizer. Just flip that plate right there. Now, at that point, you're gonna fill it with water up until this line. I use distilled water only, and with this setup, we could put probably about four blocks in here at a time, or if you're doing five pound blocks, about eight to nine.
So we'll just load them up like that, and at that point, we'll grab our lid. Will put this cord right here off to the side. Then we'll just lock it up like that, and at that point at this point you'll just tighten your lid up, making sure that the spaces around here are all even. Then we'll just tighten it up. So these things are readily available online.
This is a heavy-duty gas burner, and if you're doing this, you want to do it in like an open-air space, so you're not breathing any any fumes in. So we'll just put our players like right there, and we'll let the pressure sterilizer vent for about five minutes. Once you start seeing steam escaping from the chamber, let it continue to run for about five minutes. You're gonna basically vent any trapped air from inside of your pressure cooker. After five minutes, turn it off and let the pressure gage travel up to 15 PSI, and once it hits 15 PSI again, you're going to open up the stop cop right here and met your chamber all the way down to zero PSI.
Written protocol
Commercial Cultivation SOP Playbook
The written protocols behind this process, as run on the farm.
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Once it hits zero, close the clothes of your chamber, let it hit 15 PSI, and then pressure sterilize for two hours. After two hours you can just turn it off let these cool in your sterilizer overnight and then the next day just unload it in front of your flow hood or into a still air box and go ahead and conduct your inoculation so this is a good way to do it we we have six of these things so we could do like 24 blocks of these ten pounds or thirty six seven pound blocks a day so this is an atmospheric - steam sterilizers so this is going to take longer than our pressure steam sterilizer because number one it's not going to be getting at two hundred and fifty degree temperatures that are under 15 psi so this will be cooking miss Furyk pressure so we'll cook at around 206 to 210 degrees for 12 to 14 hours that way we get effective sterilization and we don't experience any contamination we're also cooking a lot a lot bigger a lot more substrate at once it's gonna take a little bit longer to Reach those
core temperatures we're looking for. For these ones, we're going to want it to be around 207 to 210 degrees for basically the majority of the sterilization time. It usually takes about about three to four hours to get up to core temp, and then we'll just hold it there for about ten hours. So I found that that effectively sterilizes all of our substrate, and we don't experience any contamination at this point. The guy atmospheric serialization is great, and it's really a really a good way to bulk up your production for a cost of, you know, cost-effective.
So with a large scale mushroom cultivation that involves the sterilization of like sawdust that's supplemented, we're growing out shiitake and a lot of exotic mushrooms like maitake, Pia peony, and chestnut and whatnot, and a lot of people ask if there's a way not to use plastic to cultivate the mushrooms, and you're very limited not using plastic bags that are developed for mushroom cultivation. So you can with oyster mushrooms, you can kind of get away with using reusable containers and you know buckets with holes drilled in them or laundry baskets you can get creative and use you know all kinds of stuff you can also use like reusable jars like mason jars but the yields not that good if you're just doing a quart jar of sawdust if I get just a few mushrooms so it's really hard to get away from the plastic bag being that we can sterilize our substrate in here and then effect you know opening it up in the laboratory in front of our flow hood and easily inoculate it with like buckets and reusable containers it's really hard to effectively sterilize them and then with strains like shiitake where we removed the and they fruit on all sides of the container it's really hard to do that so they also I've developed like things like biodegradable bags but there's talk about them just
breaking down into more micro plastics which might not be good either so hopefully there Is something that changes soon, and we get a biodegradable, truly biodegradable bag. But for the meantime, the bags are the biggest waste product in the mushroom growing industry. There's one species I know for sure that's been shown to break down plastics, but it's really, I mean, I guess that bee takes some infrastructure to develop a system for your farm where you can inoculate all your waste plastics maybe like once a month or something like that. So that's something that's definitely being looked into and worth more research, a mushroom that can break down plastics. So all your Petri dishes and plastic bags and all those other tools that are made of plastic that we used to cultivate mushrooms would definitely, we need a way to recycle them effectively.
So mushrooms could be the answer for that too. Also, when you get to the scale of making six hundred to a thousand bags a week, it gets harder to be able to like wash all those reusable containers every week, and if You imagine washing 600 reusable buckets every week before you inoculate, or before you load them up. So, the bags make it easy, are super effective, but if you're just growing personal for yourself, then, you know, use of reusable containers as much as you can. Compared to, like, our spawn civilization process, we utilize our All-American pressure steam sterilizers, sterilizers for a spawn, so we can effectively autoclave them at the 250 degrees that's necessary. We'll do that for about five hours.
For green spawn, it's highly nutritious, much more nutritious than our production block, so we have to be a lot more careful with our whole process, ensuring that every step of the way we're completely clean and sterilizing properly, because if a contamination pops up with our green spawn, then will make its way through all of our production blocks, which would be horrible, just a waste of time and work. So, yeah, we do utilize a higher standard of clean work and sterility when working with grain spawn. We have utilized the atmospheric steam sterilizing for a grain spun in the past, and we can do big batches at once in here, and honestly, it works just as good as long as you're sterilizing for enough time. And once you're done sterilizing, we immediately roll into our lab, so a cool-down can be done in front of the flow hoods. Oh, so with the, with these, with these atmospheric sterilizers, we definitely make sure that cool-down is done in front of the flow hoods in the cleanroom.
With the pressure steam sterilizers, we can usually let the spawn cool down in the sterilizer overnight and then open it, opening it up in front of our flow hood as it's cooled. So it's a little bit of a little little differences between spawn and substrate sterilization. So I get this last sterilizer loaded up. So, most common contaminant seen are, like, green molds, like Aspergillus or Trichoderma, which would be, like, a fuzzy green mold, and it sorts out kind of looking like mycelium, and once it's poor lights, it'll turn green. So a sport, the mycelium actually produces its own spores.
Another common common one will be, like, a black mold or a cobweb mold. You can also see a lot of different colors pop up. I mean, the most common ones I've seen in my career are just green molds, my trichoderma and Aspergillus. You can also get, like, a yeast growth, which would be, like, a bacteria. Those are really common in grain spawn, like a bacterial wet spot mold or bacterial wet spot contamination, and then, like, a cobweb mold or a green mold.
So the whole process can be overwhelming at first. Just take baby steps, and eventually it just becomes, like, second nature to start off learning the basics. Don't try to shoot too far from where you're at, and yeah, it can be really really fun and not too overwhelming as long as you just take in the right amount of information at the right stage in your learning process. So starting from, like, the beginning stages of the mushroom lifecycle, or you've been starting from a mushroom grow kit, can give you kind of, like, some of the basic ideas and fundamentals of mushroom cultivation that'll help steer you in the right direction and get you on the right path for success. And then you can always, as you begin to get more familiar with the technique, with cultivation, you can kind of, like, plan in order, like, spawn.
You could buy spawn that's already made for you in a lab, and then use that to do your inoculations and kind of just learn at your own pace. I mean, seeing a lot of contamination for your first time could, like, turn a lot of, to turn some people off to the, to the hobby, but just don't give up. Keep trying. Failure is all part of the success, so you're gonna fail. You're gonna get contamination.
It's gonna happen. It's just, it's inevitable. So just, if it does happen, just utilize it as a learning process and get. Better as you go, but every grower gets some kind of contamination or fails miserably at one point in their career. This happens, just making sure these bags are folded properly as we put them in.
They're looking great. So now the sterilizers have been loaded up. It's time to go ahead and get them sterilized, get them sterilizing. 630 pounds of fresh substrate coming through. Just plug this in, then we'll take our water, and before we turn on our sterilizer, always make sure we always make sure our water is turned on first, just because you you don't want to turn on your sterilizer without, we're forgetting to turn on your water.
Go into boiling dry, basically breaking your sterilizer. We'll hook up our temperature probe, go ahead and turn on the sterilizer, and it's at 207 degrees. Right now, it's at 70 degrees. We'll go ahead and turn on the heating element, and now the temperature will be begin to rise. Once it hits that target temperature that we have set, then our timer will kick on.
We'll start timing the process. Once it hits to the desired time that we have set, it will shut off. So all I have to do is come in and unhook it the next morning and basically wait for the subject to be cool enough to start unloading into our laboratory next door. We'll grab the next sterilizer and do the same thing over again, and we'd get that nice and tight right there so the water connection doesn't have any leaks. Switch it so on.
So this sterilizer has been hooked up. We got the power on to it. We got the water connected. Now we'll just put in our key, turn it on, turn our element on, and that's it for our sterilization process. Definitely come, you know, it's definitely a bit of a change compared to watching the all-americans on top of the high-powered gas burners and trying to play with the flame, so this is really nice, being able to just set it, forget it, walk away, come back tomorrow, and everything will be done.
We're also using an exhaust in this room to basically push out any steam and hot air, so that really helps keep the room dry and keep it cool while we're sterilizing. This is our sterilization process.