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Resterilize contaminated grain jar

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#1 raymycoto



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Posted 02 December 2018 - 05:51 PM

Thoughts on resterilizing contaminated grain jars?


I'm not talking about something really old or nasty, but jar that has shown no activity for a few days from a failed LC or such.


I had a bad batch of LC that came from a lovely agar plate. However, the LC absolutely would not grow anything in grain or PF jar. Puzzling. It seems to have had an occult bacterial colonization (I'm guessing). After about 5 days, absolutely no growth while other LC I created at the same time from similar plates were outstanding. The jars by day 5 seemed to be getting a trace of off color growth and increased wetness.


I have plenty of good LC and also plenty of grain to redo the jars. I've *nuked* the bad jars at 30PSI steam for three + hours so I'm sure they are sterile at this point. 


I realize it's not optimal. I wouldn't want to waste a limited amount of LC or other inoculant on a redo jar but I'm gonna try and noc them one more time with the known good LC. 


Seems like I tried this before and possibly had less than wonderful growth. Perhaps the contaminants leave some sort of toxin behind.


Well, I'll try it and let you know and I'll do some control jars with new grain.

Edited by raymycoto, 02 December 2018 - 05:52 PM.

#2 Ferather



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Posted 02 December 2018 - 06:29 PM

The additional cooking might cause the grain to break up or lose water, in theory it should otherwise work.

Edited by Ferather, 02 December 2018 - 06:31 PM.

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#3 raymycoto



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Posted 02 December 2018 - 06:38 PM

Ferather - thanks. I sometimes play around with weighing jars before and after PC. I've noted about a 5-10cc water loss for a quart grain jar during PC (or autoclave) when I vent the PC or clave immediately due to venting of superheated water in the jars I'm presuming. If I do a slow cooling in the clave (liquid cycle) or PC then little or no water loss.

#4 Soliver



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Posted 04 December 2018 - 09:47 PM

That's one of those 'experimental' things I've tried in the past with limited success...


If you get any growth from those jars, I'd keep them separate from other projects.


It should work, in theory, especially if you have an especially virulent strain. 


Making grain jars is a pain in the ass, and when they do nothing or go south ... it's a bummer.


Let us know how that works our for ya?





#5 raymycoto



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Posted 05 December 2018 - 05:04 AM

At 3 days, compared to the 'controls' (fresh grain jars) I'm pretty sure I'm gonna call it a 'fail' for the resterilized jars. No evidence of growth so far on anything. The controls are showing some growth but it appears that the LC for the entire experiment is not as fresh as it once was since the controls are slower than expected. 


Will update.




Making grain jars is a pain in the ass, and when they do nothing or go south ... it's a bummer.


Meanwhile, Soli, I have a tech I've worked on for making grain jars with adding exact grain grams and water plus a few things, then microwaving, a few shakes, then PC, few more shakes, wait a day or so and --> perfect grain hydration ratio, no sticky or overdone grain and good results using the jars. Not earth shattering news but I've worked out the initial problems and now think this is, by far, the easiest with fewest steps and minimal interaction needed to get the final product. I am writing it up to post when I get the chance.

Edited by raymycoto, 05 December 2018 - 05:04 AM.

#6 raymycoto



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Posted 11 December 2018 - 02:35 AM

Update on resterilization of contaminated jars.


Thanks to comments of others as well as my observations --


Hypothesis - Grain jar reprocessing due to contamination results in substrate degradation that occurs either due to one or more of the following:

  • depletion of nutrients from initial colonization
  • toxins left behind from contaminants
  • degradation of grain substrate due to repeated sterilization (carmelization or other process)

This results in a reduced suitability for propagation of the desired fungi with slowed growth increased likelihood of contamination, not due to failed resterilization but instead due to the now, unsuitable mushroom growth medium. The grower may apply 'extra' time or heat in the sterilization process in effort to eliminate the contaminants but this seems to further degrade the growth medium.


Here are two specimens, now at over one week post inoculation with a fairly potent, proven LC.


resterilize 2.jpg

resterilize 1.jpg


The darker, resterilized appears to have 'healthy' colonization but is greatly stunted compared to the control jar, which appears fully colonized.


Both grain jars were prepared with reduced hydration of 45% (9 fewer grams of water than a 50% hydration) in anticipation of a liquid inoculation. The resterilized jar lost 8 grams in the resterilization process presumably putting it at the same hydration percent as the control jar.

Edited by raymycoto, 11 December 2018 - 02:47 AM.

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