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bateyes88
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Registered: 09/15/10
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petri question
#14159957 - 03/21/11 03:38 PM (12 years, 11 months ago) |
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When storing petris, from what I understand, you store em upsidedown to keep condensation to a min. So, do I need to wrap an UN-inoculated dish w/ parafilm? Seems like contams can get into the rim of vented dishes if they are not wrapped. Ive just never noticed anyone wrapping em before noccing em. Only after.
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biologys
Mycologist in Trainning




Registered: 12/21/09
Posts: 4,622
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Re: petri question [Re: bateyes88]
#14159970 - 03/21/11 03:40 PM (12 years, 11 months ago) |
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never store dishes upside down..
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bateyes88
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Re: petri question [Re: biologys]
#14159993 - 03/21/11 03:45 PM (12 years, 11 months ago) |
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Really? Thats what the instructions on my LMA bag says... Says it keeps condensation off the surface.
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bateyes88
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Re: petri question [Re: bateyes88]
#14160000 - 03/21/11 03:46 PM (12 years, 11 months ago) |
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And people wonder why agar scares noobs. I wish there was a good, definitive agar tek. Everyone is different!
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biologys
Mycologist in Trainning




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Re: petri question [Re: biologys]
#14160001 - 03/21/11 03:46 PM (12 years, 11 months ago) |
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and incase you dont want to take my word for it
Quote:
RogerRabbit said: First things first. NEVER store mycology petri dishes upside down. It actually increases the moisture within because the water is helped by gravity to escape the agar. Always keep petri dishes right side up.
As for getting moisture on cultures in the refrigerator, it's because they don't hold a steady temperature. Your refrigerator will cycle by 4 to 5 degrees, and this causes the condensation to build up in your dishes. The solution is to keep petri dishes in ziplock bags or other storage containers, and then put them in an insulated container, such as a high end lunch box or even a styrofoam cooler within the refrigerator. RR
Quote:
RogerRabbit said: Unfortunately, your teacher was inexperienced. Condensation forms on the warm side of a surface whenever there's a temperature differential. Mycelium itself produces heat, thus condensation will form. That's why we keep colonizing petri dishes in a vertical stack. This eliminates the temperature differential and stops condensation from forming in the first place. Don't store petri dishes upside down. RR
Quote:
RogerRabbit said: I've read of people turning them upside down for thirty years. They were wrong then and they're still wrong. Laying them on their side does the same thing. The fact is, cold material can hold less moisture than warm material. As the refrigerator goes through its cycles, the temperature changes a few degrees each time. With these cycles, if your dishes are upside down, more condensation drips to the lid. It can't re-absorb into the agar on the up cycle, because it's now on the lid which is the bottom. Within a month or two, you have a dried out agar disk on top, and a pool of water on bottom.
Leave jars right side up and you have none of these problems as long as you have the dishes wrapped up. Even unwrapped, store right side up. I knew someone would come along to repeat the store upside down mistake, so I got the correct method in first. Mushworld is wrong with that advice. I should shoot a picture of my lab refrigerator. There's nearly 100 petri dishes in there, all right side up, and not a bit of condensation buildup on any of them. Most are unwrapped. RR
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bateyes88
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Re: petri question [Re: biologys]
#14160012 - 03/21/11 03:49 PM (12 years, 11 months ago) |
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I believe you, bios. Just confused. My cond is from the hot agar, not my fridge. How do I get rid of the cond from the steam from the hot agar?
And, what about wrapping. I guess I dont need to if I keep em right side up...???
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Doc_T
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Re: petri question [Re: bateyes88]
#14160038 - 03/21/11 03:56 PM (12 years, 11 months ago) |
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I put petris in a ziploc bag instead of wrapping them.
-------------------- You make it all possible. Doesn't it feel good?
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bateyes88
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Re: petri question [Re: bateyes88]
#14160060 - 03/21/11 04:01 PM (12 years, 11 months ago) |
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Thats where they are now. Do you guys get cond. from hot agar steam? Do I need to worry about it? Wont it screw stuff up when it drips down?
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biologys
Mycologist in Trainning




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Re: petri question [Re: bateyes88]
#14160084 - 03/21/11 04:07 PM (12 years, 11 months ago) |
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yes i've gotten condensation from pouring the agar, but when i stack them with in a day or two all condensation is gone..
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bateyes88
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Re: petri question [Re: biologys]
#14160178 - 03/21/11 04:25 PM (12 years, 11 months ago) |
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I poured mine last night, and I still have quite a bit. At least the top one does- I havent looked down thru the stack.
It disappears even when sealed in a zip-lok? Do you keep it open alittle? Im prob just worrying too much about non-issues, I tend to do that !
Thanx guys!
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bateyes88
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Re: petri question [Re: bateyes88]
#14160337 - 03/21/11 04:59 PM (12 years, 11 months ago) |
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There is A LOT of condensation on my covers. I just cant imagine its OK to leave it. It seems like its bound to drip on my myc.
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Belief
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Re: petri question [Re: bateyes88]
#14160494 - 03/21/11 05:32 PM (12 years, 11 months ago) |
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I pour my agar on the hot side, let the condensation form on the dishes (will be about half of the dishes). Then I use a sterile gauze to wipe the top half of those affected. Works wonders and is less stressful than measuring the perfect agar temperature without it hardening on you 
its always an awful feeling when you have 5 dishes left and a big blob of agar flops onto your dish
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egodeathflux
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Re: petri question [Re: Belief]
#14160535 - 03/21/11 05:39 PM (12 years, 11 months ago) |
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Quote:
Belief said: its always an awful feeling when you have 5 dishes left and a big blob of agar flops onto your dish
Top tip for keeping agar flowing: use one of those beer bottle cooler things, this will keep it insulated and maintain a workable temp for a little longer. Obviously any insulating material will work but I use Havana Club bottles for agar and they fit like a dream.
-------------------- "Atrophic interludes weave through my life far too often, for me to fight the biggest enemies" "Standing on the corner of 5th and Vermouth"
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bateyes88
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So Im supposed to let it cool some, then. Didn't know that. God, I hate my noobiness.
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Belief
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Quote:
egodeathflux said:
Quote:
Belief said: its always an awful feeling when you have 5 dishes left and a big blob of agar flops onto your dish
Top tip for keeping agar flowing: use one of those beer bottle cooler things, this will keep it insulated and maintain a workable temp for a little longer. Obviously any insulating material will work but I use Havana Club bottles for agar and they fit like a dream.
I use this. http://www.brookstone.com/mug-coffee-cup-warmer.html
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chains


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Re: petri question [Re: Belief]
#14161035 - 03/21/11 07:31 PM (12 years, 11 months ago) |
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Quote:
Belief said:
Quote:
egodeathflux said:
Quote:
Belief said: its always an awful feeling when you have 5 dishes left and a big blob of agar flops onto your dish
Top tip for keeping agar flowing: use one of those beer bottle cooler things, this will keep it insulated and maintain a workable temp for a little longer. Obviously any insulating material will work but I use Havana Club bottles for agar and they fit like a dream.
I use this. http://www.brookstone.com/mug-coffee-cup-warmer.html
Jeez some people are just made of money 
Lol only messing  Im just but a poor hippy so i just cool it until i can comfortably hold the bottle an then work fast.
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Mikeallojee
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Re: petri question [Re: chains]
#14161283 - 03/21/11 08:19 PM (12 years, 11 months ago) |
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I have the same issues. I have condensation in the fridge and when I pour. So far it hasn't caused any problems that I am aware of. Even if it does drip on the agar. Some people suggest to put a hot cup of water on top of the dish stack. It kinda worked but was far from perfect and I still got condensation. I haven't found a way to get away from the condensation. Ive just learned to live with it. myc
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afrosheen
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Yeah I get condensation too, but it's mainly on the top plates (and those towards the top) in a big stack. Since the lids on my petris have little nubs to let a tiny bit of air flow, I just pour them and leave them in the GB for a few days while they dry. After inoculation it's parafilm time and some of the condensation will come back, but like RR said that's due to a temperature shift. It's best to keep inoculated dishes in an area that's not subject to temperature swings, i.e. the center of a room, nowhere near an A/C or heating vent, in a cool cabinet (inside of a tub or other container), etc..
--------------------
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biologys
Mycologist in Trainning




Registered: 12/21/09
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Re: petri question [Re: afrosheen]
#14161534 - 03/21/11 09:10 PM (12 years, 11 months ago) |
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after i pour my plates i'll stack, and put in a cabinet in my house, which stays between 65-70, thats where they stay until i use them..that way i always have some ready incase i get a contam that i need to transfer away from immediately
and as i said with in 2-3 days the condensation is gone.
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