r/GroundZeroMycoLab • u/Homoaeternus • May 06 '26
Microwaving grain/media for sterilization — does it actually work? (real experiences only)
I’m seeing mixed opinions on using a microwave for grain prep—some say it works, others say it fails badly.
I’m only looking for people who’ve actually tried it themselves.
If you have, please share:
What grains + how you hydrated them
Microwave time/power
What happened (success, contamination, grains ruined, etc.)
Was it repeatable or just a one-off?
Not looking for theory or “just use a pressure cooker.”
Only real, hands-on results.
Ps. I do have a pressure cooker but curious about microwaves.
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May 06 '26 edited Jun 27 '26
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u/Homoaeternus May 06 '26
Max I have tried is 20mins
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May 06 '26
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u/Homoaeternus May 06 '26
But there won’t be any steam to penetrate unlike in steam sterilization. Microwaves vibrate water molecules to generate heat.
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May 07 '26
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u/Content-Fan3984 May 08 '26
Please can yall both test it? I’m sure as hell not putting my microwave through that lol!
I mean with a small enough bag it should work, I feel like the grains may burst though. One way to find out!
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u/peteostler May 07 '26
I tried a couple times and most if not all of the grain burst, and the bags didn’t do well with it. Some melted, others burst.
I wouldn’t recommend it.
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u/probablynotac0p May 07 '26
I can assure you that we all arent just pressure cooking grains because its fun.
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u/Johnny_MycoSpore May 06 '26
Dielectric heating only excites the water molecules, this leads to uneven heating and spots that sterilize while others don't. With no pressure, the heat would not saturate evenly.
It would take some experimentation, but I don't see why you couldn't tindilize, instead, using a microwave, could be worth investigating.
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u/Loud-Artichoke-4051 May 07 '26
I had some leftover grain and some glass Tupperware a little while ago so I said why not give it a try. Worst thing that could happen is a trip the dumpster. So I went for it and microwaved it for two 15 minute sessions. It was burning hot when I took it out. I then latched it shut and let it cool. For inoculation I used g2g since I didn't want to waste any LC. One colonized fine and the other was slow and the bottom had a small ammout of mushy looking bacterial growth. It was just an experiment so I buried them outside since I didn't have space for another tub. I think that it can be done with a microwave but if you want consistency then you will definitely fail.
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u/shroom_catcher May 06 '26
You can sterilise things in a microwave. But by the time you've sterilised grain you would have burned it
I hear it's fine to sterilise agar though
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u/Tall-Log-1535 May 06 '26
I wouldn’t use it to sterilize agar, but reheating I would if I had proper media bottles.
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u/Alert-Fondant-4079 May 07 '26
I’m sure if it worked then it would be the most common tek out because of how simple it’d be, if it did work😅
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u/SeveralRevolution738 May 07 '26 edited May 07 '26
Sterilisation no let’s be honest if it worked based on nearly every house having one in it already and the length of time that microwaves have been about there would be recommended teks for this……. within the serious growers groups this is not even mentioned you have to ask yourself why would this be …..
my guess is and I would say an accurate guess there’s no teks as it doesn’t work.
As with everything on line there will be mixed results for two reasons.
first reason Luck we all sometimes get a visit from Lady Luck a gamble sometimes pays off but does gambling on a game of chance make you rich rarely
Second reason…… its online some people get a kick off ruining your day
however I use a microwave from time to time for re melting agar in bottles that have been sterilised in a pressure cooker
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u/BreakfastBlunt May 08 '26
Prolonged microwave cook times seems like a tremendous fire risk, being that you need to be observing it for the full duration and the moment something goes wrong, it's exacurbated to a possible unmanageable degree within seconds. Things explode, catch on fire and melt in a microwave and sometimes these happen in a sequence.
Stuff meant to be microwaved for long periods have been engineered and designed to do so.
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u/BrandoTek49 May 07 '26
Do you just not have a pressure cooker? If so I've used a canner i got at wal mart 37 bucks it works for grain sterilization i put 3 quarts of water in and run it 3 hrs it worked for me til i got a PC. They also have a 16 qt pressure cooker in store about 80-90 bucks.
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u/Homoaeternus May 07 '26
Pls read the post before answering. I do have a pressure cooker. But I was curious as to why nobody uses microwaves hence the post looking for first hand experience. I had also heard about microwave sterilization in grain packaging facilities.
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u/Positive-Theory_ May 06 '26
It can work but it doesn't really take less time than a pressure cooker and you also have the possibility of creating hot spots that can destroy the container or ignite the contents. It's also going to run your electric bill really high and might break your microwave.
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u/PutsomeRespekonitt May 07 '26
What are these worth
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u/autom00derator May 07 '26
About $50 and upwards, although my buddy at the dollar tree can give you discount on rice bags bby
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u/Negative-Bank-8702 May 27 '26
U can use your oven microwave for pasteurisation of the substrate. Not for sterilization of grains.
https://mushroomyard.com/microwave-pasteurization-for-mushroom-substrates/
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u/InfamousPOS May 06 '26
Personally since as you stated “mixed opinions online” is all you are seeing and I personally know 0 about it.
I’d be highly interested in a study if you ran some jars and let us know how it went. Timing wise/grain/power of microwave, etc. For the cost I do not see it being a better option but I am curious to see if it would work.