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Grain jar sterilization - close the jar lid during PC?


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#1 raymycoto

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Posted 08 April 2019 - 02:14 PM

I will probably try this experiment but I have not and wonder what is your guess as to what will happen.

 

I find that grain jars and bags and sub for that matter gain only about 1% water wt when being sterilized in PC or autoclave. Not a problem. But I wonder if I could, in the case of jars, close the lids for sterilization. Would the jars break?  What is your guess?

 

Think about it. The max pressure differential could never be more than +/- 20 PSI and that would only be if there were sudden steam heating and / or decompression. And I think that jars could take 20PSI. But since heating and cooling is gradual, I would think that the pressure differential would be minimal. The jar might be just a bit underpressurized during heating and a bit overpressurized during cooling.

 

Well, as I was typing this I thought of a reason not to seal the jars. The negative pressure on the lid of a sterilized jar is a visible indicator of a seal and that might not exist if the jar is sealed before autoclave. And I guess a sealed jar would take more time to sterilize and if there was no water in the jar then steam would not form. Steam is an essential part of the sterilization process, not just the temperature and pressure.

 

My whole reason for even considering this is to not have to worry about screwing down the lids after sterilization. But if one is using relatively new lids with plenty of the red sealant still left then I guess they are self sealing.

 

Well, maybe I'll try it and report.  What's your guess? Broken glass or not?


Edited by raymycoto, 08 April 2019 - 02:16 PM.


#2 Myc

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Posted 08 April 2019 - 02:54 PM

If you have a solid lid - which can contain pressure - you'll want to leave that loose during PC-ing. 

 

If you have a vented lid - which can equalize pressure without mechanical manipulation - you can screw the lid tight prior to PC-ing. 

 

Otherwise, you run the risk of "popping" jars - or "blowing out" your injection ports. 


Edited by Myc, 08 April 2019 - 02:54 PM.

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#3 jkdeth

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Posted 08 April 2019 - 02:57 PM

You're using an unmodified lid? That loose lid only applies to unmodified lids.

If your lid has any kind of GE port, tighten away.
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#4 Billcoz

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Posted 08 April 2019 - 04:50 PM

You can sterilize water/other stuff in jars by PCing, the lids form a vacuum seal, but why would you use spawn-jar lids with no GE holes? I have heard claims of people doing that, IDK why exactly. There would normally be a lot more liquid in jars when canning stuff, so IDK if it would break the jars or not with just grains, try it.


Edited by Billcoz, 08 April 2019 - 04:50 PM.


#5 jkdeth

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Posted 08 April 2019 - 05:03 PM

There's actually quite a few using unmodified lids. They use the one piece lids, but never tighten them.
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#6 Billcoz

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Posted 08 April 2019 - 05:06 PM

Yeah JK, you were the person I first heard that from, do you know what the benefit would be? 



#7 jkdeth

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Posted 08 April 2019 - 05:08 PM

If you had regular unmodified lids, fully tightened, its not glass breakage that's the problem, the lid can bulge and not form a proper seal. Not something typically applicable to our hobby, but more important for food storage.
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#8 raymycoto

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Posted 08 April 2019 - 05:23 PM

I do all my grain jars with lid and ring seal but with the ring loose. When they properly seal down then they  have more or less unlimited shelf life. Although I would never really claim this. But I've used them up to 6 mo and like food in a jar, it should last a long time.

 

They key here is that I inoculate in a flow hood and so I don't really need the SHIP, although I think that the SHIP should provide a potentially cleaner inoculation. That is, there is still some chance for contaminants even with lami flow. I need to do a contaminant test in my hood. I'm sort of afraid of what I might find.

 

And I'm pretty sure a SHIP does not provide a totally air tight seal. It's a really good seal, but I would think that jars might either dry out or contam after a while with a SHIP in the top. I have had a number of jars go bad from drying out. These are the ones where I glued a filter to a hole in the top, although it takes a lot of time for that to happen.

 

But it's great not to have to modify my lids anymore although I have a ton of modified ones from last year so I'm free to go back to that tech at any time

 

OK . . . this is, IMO, a great technique and alternative to a filter and I think I may have talked about it before. I'll have to find pics. I think I even got it from the forum.

 

I open a grain jar in the lami flow and inoculate it. Then I simply insert a 5" x 5" sheet of surgical PP5 filter drape material between the lid and the jar (under the lid and ring). Then replace the lid and band and screw it down. Doesn't seem like it but this provides plenty of 'leak' around the entire perimeter of the jar but it has to go thru the threads and thru the filter drape. So far, so good for me on this.  I PC about 20 of these sheets at a time and keep them in a candy tin that's about 8" dia. and I sterilize them in that tin.

 

I've checked CO2 and it's never too high and it's comparable to a filter glued over a hole in the lid.

 

I'm pretty sure you could also use Tyvek squares for this as well. We throw away mountains of this drape material daily and it's mostly clean and a little goes a long way.


Edited by raymycoto, 08 April 2019 - 05:24 PM.

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#9 jkdeth

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Posted 08 April 2019 - 05:39 PM

Well, you're kind of doing your own thing there. Sealing jars of grain and keeping them for months is pretty unusual. But, yes, for that you need the lid not fully tightened.

On another note, I've had success with a regular polyfil vented lid after sitting for weeks.
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#10 jkdeth

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Posted 08 April 2019 - 05:45 PM

When I mention people using unmodified lids for grain spawn, that was something different. In that case you don't want seal, because you don't want vaccuum. Do this you use the plastic lids, be seal rings, just like no pour agar jars. Leaving the non sealing lid slightly under tightened provides all the GE neccesary.
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#11 raymycoto

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Posted 08 April 2019 - 09:40 PM

 

When I mention people using unmodified lids for grain spawn, that was something different. In that case you don't want seal, because you don't want vaccuum. Do this you use the plastic lids, be seal rings, just like no pour agar jars. Leaving the non sealing lid slightly under tightened provides all the GE neccesary.

 

Nice idea. I have some of the plastic lids but have not used them much and I got some silicone rings. Leaving it slightly open - I could see that would work.

 

And thanks for the insight on the polyfil vented jar. Perhaps is does a pretty good job at filtering to a small particle size. Do you PC with the poly or add it when you remove the jar from the PC?



#12 jkdeth

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Posted 08 April 2019 - 10:03 PM

Pc it with the poly, covered with foil.
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#13 Billcoz

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Posted 09 April 2019 - 06:14 AM

Well, you're kind of doing your own thing there. Sealing jars of grain and keeping them for months is pretty unusual. But, yes, for that you need the lid not fully tightened.

On another note, I've had success with a regular polyfil vented lid after sitting for weeks.

I have used 6+ week old sterilized popcorn that was sitting at room temp with micropore filters covered with foil and had success with them, they did look a little dry but still colonized in 2 weeks or less.


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