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Wienerwoods
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Registered: 07/31/16
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Using the oven for... Wait for it...! sterilization?
#23494808 - 07/31/16 07:29 AM (7 years, 5 months ago) |
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Okay, so first off, I do know that ovens are generally no good for sterilizing. I have also searched for this stuff a lot but I've been unable to find anything conclusive since my question is quite specific.
I recently did my first jar of grains. I used oats. The way I prepared them is as follows:
Boil until starch turns translucent, steam dry (probably didn't allow quite enough time for this), load in jar (about a pint), pressure cook for 120 min at 15 psi, inoculate (multispore).
The jar lids have two holes on the opposite sides. One hole has a blob of rtv silicone on both sides of it, one is covered with two layers of micropore tape (on the inside and on the outside). The micropore tapes don't touch. I think.
The grain colonized really nicely for almost a week until I saw a few colored spots that looked just like bruising I've had before. I didn't think much of it since I had shaken the jar every now and then for the first few days until I finally figured out I shouldn't.
Fast forward some 30-40 hours and it became pretty apparent that it's actually a green mold of some kind. I was only 80% sure but decided against waiting to find out. I then secured the openings on the lid with a strip of duct tape in case it would stink and pressure cooked for 90 minutes.
Meanwhile, I read about some folks actually re-using lightly contaminated stuff after sterilizing with decent success. So I thought what the hell, it might work. There's nothing at stake here.
There are three things I might have fucked up.
Fuck-up #1: Spore syringe got contaminated in the making -I've had success before so I know how to
Fuck-up #2: I didn't flame the needle -The syringe was used only once so I though isopropyl alcohol would do the trick. Really stupid in hindsight.
Fuck-up #3: Micropore tape got wet in the pressure cooker and mold was able to germinate through it and infect the grains while shaking -I was actively wiping it with isopropyl alcohol as it was drying out. No idea if that just makes it worse.
Oh, and I did use a still air box that's fitted with gloves.
So, now to the actual question: The micropore tape is wet after pressure cooking. Duct tape doesn't keep it dry and neither does a foil lid...
Can I dry and possibly sterilize the wet micropore tape/lid by putting the jar in a 300 degree oven for, say 30 minutes? Because that's what I did.
I then turned off the heat and left the jar in there to cool down. I'm going to inoculate again but I'll flame the needle this time. And I won't shake the jar.
I would also like to know a way to keep the GE filter dry.
Any feedback is more than welcome!
Also, here is a picture of the contamination when I first spotted it. http://imgur.com/U4zHdZB.jpg
Edited by Wienerwoods (07/31/16 07:32 AM)
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weetsie
unlicensed tub surgeon



Registered: 05/08/11
Posts: 572
Loc: United Kingdom
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Re: Using the oven for... Wait for it...! sterilization? [Re: Wienerwoods]
#23494850 - 07/31/16 07:49 AM (7 years, 5 months ago) |
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micropore tape is no good as a filter, use a filter that works in the first place and drying it after PCing wont be a concern.
I don't think sterilizing and reusing contaminated grain is a good idea at all, start fresh.
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spacechildo
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Re: Using the oven for... Wait for it...! sterilization? [Re: weetsie]
#23494918 - 07/31/16 08:28 AM (7 years, 5 months ago) |
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if I understand it correctly its not the grains he wanna save but the jars/lids? those gets sterilized next time you run them in your PC with grains.
but an oven arent exactly efficient as a sterilizer, use your PC.
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weetsie
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Registered: 05/08/11
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Re: Using the oven for... Wait for it...! sterilization? [Re: spacechildo]
#23494933 - 07/31/16 08:35 AM (7 years, 5 months ago) |
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>Meanwhile, I read about some folks actually re-using lightly contaminated stuff after sterilizing with decent success. So I thought what the hell, it might work. There's nothing at stake here.
I figured this meant he was gonna reuse his contaminated grain after sterilizing it.
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PsilocyBen17
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Re: Using the oven for... Wait for it...! sterilization? [Re: spacechildo]
#23494943 - 07/31/16 08:43 AM (7 years, 5 months ago) |
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I've been pondering oven pasteurization for cvg sub, I think it would be super nice to buy some tinfoil trays that fit a mono perfectly and pasteurize in that, even if I had to start on the wet side of field capacity to make up for a bit of water loss...
OP- Glad to see you have done some research before diving into grain. Despite you contam you are off to a good start. synthetic filter disks ,polyfill, ez-felt disks disks all work well for filters. Some people use tyvek but I'd hesitate to suggest it if you can get your hands on other stuff....
The biggest mistake folks commit when switching to grain is using a spore syringe for inoculation. Try putting your spores on agar first. Its not as hard as it sounds and if done correctly will give you a much lower chance of contaminations. Spores are inherently dirty, spores from vendors aren't harvested in clean conditions.
keep it up and let us know how your next attempt goes.
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spacechildo
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Re: Using the oven for... Wait for it...! sterilization? [Re: PsilocyBen17]
#23494947 - 07/31/16 08:45 AM (7 years, 5 months ago) |
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why not just bucket tek? dry heat is so much slower/has less energy than steam!
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NDStepp84
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Re: Using the oven for... Wait for it...! sterilization? [Re: Wienerwoods]
#23494963 - 07/31/16 09:00 AM (7 years, 5 months ago) |
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Alcohol dosen't sterilize it sanitizes, the reason PC's are used to sterilize grain is at normal atmospheric pressure water boils at 212 degrees, in a PC at 15 psi it can be 250 degrees or so without boiling. In an oven it wouldn't reach any higher than 212 until all the water was boiled dry out of the grain due to cooling from evaporation. Grain is cheap, especially oats best to start fresh. I and others run oats for 2 hours @ 15 psi, endospores are a bitch.
Eat has an oven pastureization oven tek for bulk substrates, but grains require a pressure cooker. Coir can be prep'd in a bucket as said and in an oven bag in the oven with the oven set lower than boiling point like in Inoc's tek, it's really sterilization which is fine for coir but hpoo, straw, ect needs to be properly pasteurized.
For lid filters my advice would be use synthetic filter disks or unmodified plastic lids
--------------------
"I am free, no matter what rules surround me. If I find them tolerable, I tolerate them; if I find them too obnoxious, I break them. I am free because I know that I alone am morally responsible for everything I do. -Robert A. Heinlein
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PsilocyBen17
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Re: Using the oven for... Wait for it...! sterilization? [Re: spacechildo]
#23494966 - 07/31/16 09:01 AM (7 years, 5 months ago) |
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I've never bothered with the bucket tek because I've only ever here people whine about it for coir/verm subs, but I'll certainly give it a try. I'm at a point where loading up mason jars for pasteurization in a stock pot is just too much work/mess
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spacechildo
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Re: Using the oven for... Wait for it...! sterilization? [Re: PsilocyBen17]
#23494970 - 07/31/16 09:04 AM (7 years, 5 months ago) |
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Quote:
PsilocyBen17 said: I've been pondering oven pasteurization for cvg sub
Quote:
PsilocyBen17 said: I've never bothered with the bucket tek because I've only ever here people whine about it for coir/verm subs
hmmm. I dont get it. you are using cvg, so why not bucket?
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PsilocyBen17
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Re: Using the oven for... Wait for it...! sterilization? [Re: spacechildo]
#23494976 - 07/31/16 09:08 AM (7 years, 5 months ago) |
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I'll certainly give it a try if your suggesting it. I have a bucket and a giant 90gallon tub that would work perfectly
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spacechildo
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Re: Using the oven for... Wait for it...! sterilization? [Re: PsilocyBen17]
#23494985 - 07/31/16 09:12 AM (7 years, 5 months ago) |
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90 GALLON tub?? wtf kinda bucket tek are you following? 
thing with coir is just heat it/cook it at as high a temp as you can. we're just looking to break down the lignin and make the food more available. Monitoring temps when making CVG has no point, just get them as high as you can. I insulate my bucket tek bucket with another bucket with boiling hot water in, and add a ballast (pot of water) to sink the CVG bucket into the hot water bucket.
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PsilocyBen17
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Re: Using the oven for... Wait for it...! sterilization? [Re: spacechildo]
#23494996 - 07/31/16 09:19 AM (7 years, 5 months ago) |
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Hahahaha 90 litres. whoops. Canadians have it tough of these boards sometimes.
Yeah I've been reading that about cvg lately. I've been into edibles for the last year and but that seems to be the new train of thought with cvg....I guess I can save the meat thermometer for another hobby?
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PsilocyBen17
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Re: Using the oven for... Wait for it...! sterilization? [Re: spacechildo]
#23494997 - 07/31/16 09:20 AM (7 years, 5 months ago) |
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Hahahaha 90 litres. whoops. Canadians have it tough of these boards sometimes.
Yeah I've been reading that about cvg lately. I've been into edibles for the last year and but that seems to be the new train of thought with cvg....I guess I can save the meat thermometer for another hobby?
Do you still keep it hot for 60-90 mins? or do you not worry about that either?
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spacechildo
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Re: Using the oven for... Wait for it...! sterilization? [Re: PsilocyBen17]
#23494999 - 07/31/16 09:22 AM (7 years, 5 months ago) |
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save it for manure, peat based casings etc!
its been said about coir for "ever", the bucket tek works because temps arent important, otherwise it'd start out too hot and most likely start partial sterilization of your sub.
I keep it in the bucket until its cooled down on its own, aim for max temp for as long as you can hold them.
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NDStepp84
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Re: Using the oven for... Wait for it...! sterilization? [Re: PsilocyBen17]
#23495014 - 07/31/16 09:29 AM (7 years, 5 months ago) |
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Usually give it a stir after 30-45 min then let it cool down on its own. I usually break up the brick with a knife a bit, 2 quarts verm and a small amount of gypsum, pour 5 quarts of boiling water on top snap the lid on and that's it. No benefitial microbes to save in coir, you could even pressure cook it in jars if you wanted to. If it contaminates you can bet it was your spawn. Since I use CVG for a bulk substrate all I ever properly pasteurize is peat based casing.
--------------------
"I am free, no matter what rules surround me. If I find them tolerable, I tolerate them; if I find them too obnoxious, I break them. I am free because I know that I alone am morally responsible for everything I do. -Robert A. Heinlein
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PsilocyBen17
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Re: Using the oven for... Wait for it...! sterilization? [Re: NDStepp84]
#23495027 - 07/31/16 09:36 AM (7 years, 5 months ago) |
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Cool shit.
Speaking of which. If I used manure with my CVG I guess I could just properly pasteurize it seperatly and add it in later yeah?
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spacechildo
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Re: Using the oven for... Wait for it...! sterilization? [Re: PsilocyBen17]
#23495030 - 07/31/16 09:37 AM (7 years, 5 months ago) |
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yup!
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Wienerwoods
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Re: Using the oven for... Wait for it...! sterilization? [Re: spacechildo]
#23501567 - 08/02/16 11:37 AM (7 years, 5 months ago) |
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Okay, maybe I made the op a bit of a mess but I'm nevertheless very glad to see so many responses in such a short time!
I've been under the impression that micropore is adequate for blocking airborne contaminants but the more I read about it the more I want to get rid of it and get some synthetic filter disks. I know it's not a bright idea to re-use the grain (that's exactly what I'm trying to do), especially when it's so readily available, but it's something that I felt the need to experiment with for myself. I'm not seriously expecting to gain anything but experience from this.
What I originally wanted to know was if the 300 degrees fahrenheit of the oven would be enough just to dry out the micropore tape and keep it clean enough so it won't wick contaminants through, because I'm seriously suspecting it's the filter's fault there was mold in the grain in the first place - the oats did hit the filter when shaking the jar.
I went through some threads on similar problems with wet filters and it seems the best way to dry the filter is to let the pressure return back to normal and taking the jar out of the pressure cooker while it's still hot so the filter gets steam dried. However, my question still stands.
I've got some healthy growth in the grain once more and this time I haven't shaken it. We'll see if it goes bad again if I don't touch it.
Oh, and petri dishes are in the mail so I'll be able to delve into agar soon!
Edited by Wienerwoods (08/02/16 11:41 AM)
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spacechildo
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Re: Using the oven for... Wait for it...! sterilization? [Re: Wienerwoods]
#23501619 - 08/02/16 11:55 AM (7 years, 5 months ago) |
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tmethyl re-used his contamed grains, should be in his main threads!
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Wienerwoods
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Re: Using the oven for... Wait for it...! sterilization? [Re: Wienerwoods]
#23516493 - 08/06/16 04:59 PM (7 years, 5 months ago) |
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It's been over a week now from inoculation and I thought I'd update.

The mycelium is colonizing the jar really nicely and the dead mold has all been eaten soon. No signs of contaminations yet so I'm pretty sure the mold germinated through the micropore on my first try. Pressure cooking messed with the moisture a bit even though I tried to cover the GE hole properly. Still, I'm pretty happy with how it's looking so far.
Edited by Wienerwoods (08/06/16 05:02 PM)
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