Skipping grain inoculation

Let’s say I had a massive amount of liquid culture and I wanted to inoculate monotubs.

Would I be able to bring my bulk substrate up to field capacity using liquid culture instead of water?

Would there be any significant increase in colonization rates?

1 Like

TBH Iv never tried this. My 1st thought, a monotub takes a whole lot more room vs a spawn bag. I bet I could fit 5 maybe 6 spawn bags in 1 of my tubs. I’m referring to physical space.

Not sure how that could save you time, unless you were doing 1 or 2 tubs.

You would definitely need to sterilize everything that goes in your tub, that would take extra time.


I’m assuming potato water with maybe some malt extract for the liquid culture right? And you have this in shaker flasks? It’s been a while but I used to inoculate a strong liquid culture into autoclaved bags of 80/20 oak mulch and used coffee grounds (free from Starbucks). The result of a strong inoculation is that you have way fewer worries about contamination taking root. It is kinda like pitching a strong yeast culture into your beer or cider to kick it off. With the monotubs, you will have a much harder time sterilizing in the first place so a strong starting culture is probably wise.

I was growing oyster mushrooms so the media you wet out may be quite different but ultimately not hugely different in effect. Its hard to overfeed fungi so its not like extra potato starch or malt extract is going to fuck things up over just more water.


1 Like

This won’t work. The only time you’d ever want to put LC straight to substrate is when you’re cultivating Cordyceps militaris.


So skip the grain colonization and inoculate bulk with strait liquid culture? Mmm I’d think the grain is going to have lots of nutrients that won’t be in your bulk, and then you’d have lost that. Yeild would probably suffer.

Also I could see the extra sugars added from all that LC might lead to higher probability of contamination in the bulk.


So we did bulk inoculation from LC for years. We used potato dextrose and malt extract in 4 liter flasks that were 1/4 full and set on orbital shakers. Before inoculating the bags, we hit the LC with a tissue blender and then topped it off with more LC medium to get a fluid volume appropriate for the bags we were inoculating. A portion was reserved to start the next flask off and the rest was dumped into the bags. It has been a while but I want to say they each got about half a liter. Bags looked pervasively colonized in a few days. Mostly doing blue and elm oyster mushrooms. I think we did do a ganoderma once too but never could get it to fruit.

Grain won’t have any more nutrient value than the malt extract since it is just the edible parts of grain in liquid form. My approach is probably more expensive in material but rather low in labor time. Won’t cost that much to try it.



It’s in 2 liter Mason jars that are in an incubator shaker.

How are you dealing with air exchange in the jars?

The only challenge I can really see is sterilizing something to grind the balls of fungi up with. Best I can think of is soaking an immersion blender wand in 70% EtOH 1% peroxide. Unless you can find one that is all metal that you can just autoclave or sterilize in a pressure cooker.


Think I could just put one of those little protein shaker balls in each if the jars and just shake en up to break up the mycelium?


How about ultrasound? Think I could fix a mason jar lid to a transducer so I can just swap the lids, flip the jar upside down and turn on my transducer to break up the lumps of mycelium?

Think the ultrasound would kill the mycelium?

I was thinking if just unscrewing my transducer horn and cutting a hole in a mason jar lid big enough to fit the threads of the horn through, then just screw it back up.

Not a fucking chance of shaking them to break them up. Give it a run until you get wankers elbow and the compare before and after pictures…

The disrupter will not break up the balls but will decrease cell viability. I did this exact thing with a 1000W disruptor and it did essentially nothing to clumps and decreased viability by about 75% after 30 seconds with the ground tissue on ice to keep the disruptor from cooking it.

Aslo, I hope you are wearing hearing protection while using that disruptor. They will quickly do damage if you aren’t. We used to trigger the 1000W disruptor from another room because even with plugs and muffs it would make the roots of your teeth ache.



I guess I’ll put a drill press in my flow hood lol.

Lmao wankers elbow


I’ve always heard you gotta go to grain first. Not sure why but the people who know mentioned it.

I have seen someone use stir bars, and one dude used a screw, in the liquid cultures, and would just throw them on the stirrer for a few seconds

Looks like this might do ok. You can take the wand off to sterilize it by pretty much any standard approach. The tissue blender I used wasn’t hugely different other than in price…

I was blending to more or less very watery applesauce in texture. You just need a few cells to get something started so it can be pretty fine. You want to do the grinding while in log phase growth. For us 3 to 4 days after starting a liquid culture up was pretty optimal. YMMV but if you look at settled volume you will have a good idea of how it is going.

Whatever goes into LC to start it will just get bigger, it won’t really break up so getting relatively fine ground mycelia into the starter will work to your advantage. Its why doing the next starter from the ground up batch you are inoculating with works well. Just be cautious about doing more than 5 passages like this. You will get culture abnormalities if you keep going too many cycles. Inoculate a MEA plate without chloramphenicol each time you grind so you can see if you fucked up and have bacterial contamination.



You can do it, but the substrate needs to have supplements (like bran) and be sterilized in mycobags, not pasteurized.

I did it for a few runs at my oyster farm, but stopped because I figured out how to inoculate with just 1/4 cup grain per substrate. With 1/4 cup grain for each bag I get 80+ substrates from a single bag of spawn. I only do 288 subs per week so I can run my AA75X once with six spawn bags, lose two bags of spawn, and still have enough. I need 4 bags weekly, so cooking 6 at a time allows me to skip every 3rd week of making spawn.


i feel as though this will only increase your rate of contamination due to the unpredictability of the sterility of each culture. once a dirty syringe aspirates from your LC container the whole thing is garbage.


You are correct, and that’s the main reason why I stopped doing LC and learned to stretch my grain. I did a test plate from each 60mL syringe, they were all clean, then I lost every bag from 120mL worth of LC. That cost me like $1200 wholesale, and $2400 at farmer’s market pricing, not a lesson I need to learn again.

I would rather wait another 4 days for a bag to colonize from solid spawn than risk using LC.

1 Like

4 posts were split to a new topic: Know your substrate

4 posts were merged into an existing topic: Know your substrate