Inside a Real Commercial Mushroom Lab | The Mushroom Grower Vol. I: Lab Work
Anything to do with making your own cultures or growing out grain spawn or to the production of your mycelium in culture form is the most important part of your mushroom growing journey or part of the process. Yeah, this is just basically like a simple room. It's like an 8 by 12 room that I've converted into my laboratory. Um, at one point I was just utilizing like a small walk-in closet at home that you can convert into a lab. A lot of people can convert like pantries or small spaces uh, to basically make an efficient lab space to do all your clean work, transfers, spawn production, uh, you name it.
So, uh, through the years I've kind of just added an additional flow hood as my, uh, my workload grows. So, uh, now I have, uh, basically 10 ft of this clean clean work space to do transfers in front of and it really allows me to to do a lot at once, which, uh, I really enjoy. So, yeah, the lab, uh, at this point is basically 10 ft of, uh, HEPA filtration. So, it's just, uh, a few HEPA filters that are built into these cabinets. Then there's a housing atop uh, uh each of cabinets that has a blower attached that basically pulls air in and pushes it through the help of HEPA filter at a rate that basically makes sure that air coming out of the filter is sterile and free of any kind of airborne particulates or any contaminant or you know, I'm a vector of contamination.
Uh you know, I'm the dirtiest thing in my lab. Uh so before coming in I I make it like a routine make this work the first start of my day like after I've come from fresh shower and uh you know, making sure that I'm hygienically clean. Get bacteria blooms in a matter of hours compared to the the rate that the mycelium grows out at. So it's very important to make sure that if you're like listening to some music uh you're not like singing in the you know, during the course of your transfers cuz you know I mean I've even read where a researcher was doing some singing while they were working in front of their plates and they were getting a lot of contamination. Uh and once they kind of noticed that they stopped and the contamination went away.
But for years uh I basically didn't have any of this equipment. I started growing mushrooms at 16 years old and um I basically would find things around the house to to create a little sterile environment to work in. And I remember my first glove box was kind of just like a cardboard box lined with foil aluminum foil then it had two holes cut in the front and it had uh some household like those those really long cleaning rubber gloves those vinyl ones. So I had those taped into the inside and then I covered the top of the box with like a clear film uh like one of those things that when you buy like a uh like a comforter you get like those those zip up little plastic things. Um I covered that and uh was able to do my transfers in there.
That was kind of like our first rough glove box and it worked fine. But it really all falls in with the with the cultivator and your sterile sterile technique. I mean, you can still have flow hoods and still get contamination if you just don't have the proper technique of uh just your work. Sterile technique. That means uh you know, breathing uh during inoculations shouldn't really be done.
Um and the way your movements are placed. Is your hand in front of your your you know, is it in front of your open container where uh you know, a possible spore or skin cell even can fall into your substrate and wreak havoc actually on your on your grow. So yeah, I have some liquid cultures that I've been working on here. Um we have some lion's mane and a couple oyster species. These have already been used to create spawn, of course.
Um so yeah, I'm examining some of the spawn that I have here and this is one of our blue oyster strains. Uh this was inoculated uh just 10 days ago and it's looking amazing. Uh then we have some lion's mane that was just inoculated 10 days ago as well. And then here next to it, we have our pink oyster. You can notice the mycelium's pink.
Um every mycelium's going to be different for each strain. So it's pretty cool. You're going to see these own unique characteristics here mycelium and that once you become you know, rather familiar with the cultivation process, you can really identify uh strains just by looking at the mycelium. So like this right here is the shiitake mushroom. And you can notice this is actually an age culture.
Written protocol
Southwest Mushrooms Genetic Library
The strains themselves, the same cultures used in this footage.
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This is inoculated uh March 9th. And uh it starts to brown, which we'll see in our production blocks as well. Uh as it ages, the mycelium browns. A lot of new cultivators will get scared and think it might be a contamination, but it's actually really healthy and uh it's totally natural. You just can't refrigerate it.
So, it means that it's going to grow out really quick and I mean, it's going to need a transfer here sooner or later. So, like with the pink oyster, yeah, like every 2 weeks to every 4 weeks, I'm in here transferring it into new new plates. So, it doesn't uh experience senescence. It's We're basically just trying to back up the whole uh the whole library. This is basically the the majority of the strains we grow, not all of them, but we're just turning it all into a liquid culture reserve to just have on hand as well because uh sometimes it's really nice just having that liquid culture available.
The backt incinerator or just uh tool transfer tool sterilization unit. I use it to sterilize my scalpels and syringes, anything that's going to come into contact with the sterile culture. So. Now, I'm going to just be wiping down stuff with some isopropyl alcohol, cleaning my uh my work top, cleaning any of my surfaces. So, yeah.
Um basically, this is prepared by mixing malt extract agar uh powder into uh 1 L of water and then sterilizing in uh an autoclave uh for about 30 minutes. Uh after that, it's poured while the media's still hot into these Petri dishes and allowed to cool. Once it cools, it gela- uh solidifies and it forms a It kind of gels and it forms this nice two-dimensional surface that our mushroom mycelium can grow across and we can select the healthiest spots of growth to basically get optimum results for our mushrooms. So go from there with this. So for each transfer, we're re-sterilizing our tool making sure that we're not going to cross contaminate cross-contaminate any of our work.
So this this part of the process can be kind of intimidating to some people, but once you kind of start grasping more of the concept, it becomes rather easy and really I really too too aggressive. When I'm doing my transfers, I like to put the wedge kind of face down onto the plate. That way the mycelium just grows directly into the agar and I just giving it that little boost. One technique for for transferring with your Petri dish is called like a clam shell technique is where you take the dish and only lift up this much and close it right back up. That's a good way to use utilize if you're just looking for a quick transfer in these dishes that I've made and kind of transferring them furthering them to more plates.
If realistically, you can make up to 40 new plates with each Yeah, the mushroom mycelium in a Petri dish will grow flat across a two-dimensional surface and then in a liquid culture, we give it basically a way to grow out three-dimensionally through all sides and and in every way possible. And also another thing about liquid culture is the fact that you can take just a tiny piece of tissue from a petri dish, drop it into a liquid culture jar, and really just expand the mycelium. I like to utilize the liquid culture for those with about 6 to 800 ml of water. Uh it's been pressure sterilized uh to basically rid it of any contamination or mold spores. Uh at this point, it's completely clean.
We'll drop pieces of tissue into each of these jars. They're all equipped with a magnetic stir bar, so I can put it on a stir uh stir plate, and uh this will spin and break up any of the mycelium uh basically further expanding it through the liquid. And then once it's expanded to a point where it's basically just a little bit of nutrition to basically uh be able to hold with uh sustain mycelium growth and development. But, you can use a lot of different recipes for a liquid culture. You know, light malt dextrose or, you know, honey is a good one, like a tablespoon of honey per 500 ml of water.
Uh in this case, we just do 2 tsp of dextrose or light malt dextrose per 500 ml of water. I'll just turn on the stir bar and start agitating the mycelium. Hopefully, little fragments of mycelium fall off and get spread throughout the water and form like a chain of uh growth that we'll see over the next few days. We'll keep monitoring our cultures and actually coming in here and stirring them up um for 30 seconds, 15 to 30 seconds per jar every day until we get a really nice growth of uh nice mycelium. And I'll just get some of these uh fully colonized cultures, so you can see the My is pretty uh It's taking over the liquid quite a bit.
Now you can see a nice nice mass of mycelium in there. So, I'll go ahead and start agitating the mycelium, making it easier to take up into our syringes. Say you got a syringe with a liquid culture in it. Uh you can make up some jars of liquid culture and inoculate them with just like one drop of your own liquid culture solution and just create thousands of milliliters of your own liquid culture. It's a fast way to expand out your mycelium.
All right. Uh each of these jars will make 40 syringes. Uh each of these syringes are about 12 cc's. So, a little bit over 40 syringes. I have 500 ml of an inoculant in here.
And yeah, each jar turns out to quite a bit. With each of these syringes, you can inoculate hundreds of more jars of Or each syringe can inoculate uh 12 lb of grain. This is our white proso millet. Uh you can use a multitude of grains to cultivate your spawn. Uh ranging from millet, which is uh my most desirable.
We've also used uh soft red winter wheat or other various wheats, rye grain, uh basically whole rye berries. Uh also, another favorite of mine is uh milo or sorghum. It makes a great grain. You get these nice spherical grains. But uh millet, I found is the the optimum one.
I mean, you can really stretch your spawns. And we have our moisture content. The reason why I like this method of producing grain spawn as well is because it's really little to no waste. All the water that we're using and all the grain uh gets added and sterilized, and we're not wasting any water. There's other methods where uh grain is required to be soaked for 24 hours, and then after that, it's rinsed repeatedly until the water runs clear, and then after that, grain is laid to dry out on the table till you get the desired moisture content, after which it's placed in your sterilizers and sterilized.
I found that it does Uh everything has to be sterilized pre-inoculation, so we kill off any uh basically endospores, mold spores, or bacterial contaminants uh that can also compete with our mushroom mycelium's precious food source. In these bags, and then at that point, we can load them in our sterilizer and uh sterilize them for 4 hours between 15 to about 15 PSI, 15 to 20 PSI. After that 4 hours, we will allow them to cool overnight in our laboratory, and uh commence the inoculation process the day after. The generation one grain spawn bag is basically a bag that will inoculate straight from like an agar wedge uh directly into sterile grain. Uh once that bag's colonized, we can create uh generation two bags, so each of those bags is utilized to inoculate 10 more bags, um and those bags will be used for production.
Uh you can keep going to a generation three, so one agar wedge can become two of uh these spawn bags. Now, after the wedges are in the in the sterile grain, we can just break them up, and that'll actually break up the mycelium, and we'll be able to spread it further throughout the grain. Now, there's just an increased colonization rate. So, that grain spawn is an important step into the production. Instead of going from like a liquid culture or straight from Petri dish into like a sawdust production block, we prefer to go grain spawn to production block because one you get more inoculation points with the grain spawn.
Each individual kernel becomes a vehicle to basically a vehicle to carry our mycelium into our sterilized substrate. So, with just like a small handful of these grains, you get, you know, 100 or so inoculation points. And that really speeds up the colonization process and also the added nutrients coming from the grain spawn, like the, you know, certain nitrogen benefits and and starches and sugars that the mycelium actually feeds on and that utilizes our mycelium will utilize the nutrients to boost yields and to get better Turn this one bag into 10, those 10 into 100, those 100 bags inoculate 20 to 30 production blocks. Now you're at 3,000 blocks from just one single wedge of tissue. And with that, I mean, we can inoculate 1 lb of grain spawn per milliliter.
So, with that, that's 50 lbs of grains or 500 lbs of grain spawn. And then that can actually be turned into another inoculation of 10 times its original inoculant. So, we're looking at 5,000 lbs of grain spawn from just one jar. That 5,000 lbs can be used to inoculate tons of sawdust substrate. So, it's just super important to get this right because it's going to eventually be used to grow over 100,000 lbs of mushroom.