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Potato dextrose agar-petri Dish


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#21 Myc

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Posted 15 March 2014 - 11:36 AM

 

Blowing my mind here Myc!

 

I usually make a half batch cause I rarely need 50 half pint agar jars at any one time.  This nugget of myco gold could save a bunch of time for me.

 

EDIT: Upon thinking about this a bit more, I wonder if this method would be smart to employ using half pint jars that have been sitting around on a shelf.  It is much easier for my mind to compute using this method for a sleeve of new sterile plastic plates.

 

What are your thoughts Myc?

 

 

I'm not sure if I completely follow but I will attempt a guess:

 

You're asking if you could pour say......50 half-pint jars as "plates" for future use?

I have studied this type of storage. 

The agar, when poured in small amounts and stored long-term, seems to change state and become grainy and soupy.

I have tried several methods of storage:

Plates in the freezer - short term (less than one month) and they're OK. Longer than one month and they change state as noted above.

Plates in the refrigerator - about a month in the fridge is OK. Depending upon how thick you pour your plates, your mileage may vary (I use 8ccs/plate).

After a month in the fridge, the agar begins to dry. Once the agar dries enough, it becomes useless for fungal propagation purposes.

Plates just left out to sit - poured and stored in the original sterile sleeve. Without fail, these plates always contaminated (at least one or two in the stack) - the stack was thrown out and this method was abandoned.

 

When storing agar "bulk" in quart jars - take care when nearing the end of the batch. Best to use it up after there gets to be less than 1.5 inches or so. For some weird reason the agar changes state. When poured, it remains grainy and soupy in texture and is useless for fungal propagation.

 

I like to play with agar and have a few threads lingering around here somewhere showing some of my experiments in detail.

https://mycotopia.ne...in-the-freezer/

 

Here's how I do tissue syringes. Scroll down to post #24:

https://mycotopia.ne...nt-fungi/page-2


Edited by Myc, 15 March 2014 - 11:47 AM.

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#22 roscoe

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Posted 15 March 2014 - 11:46 AM

 

I'm not sure if I completely follow but I will attempt a guess:

 

:biggrin:

 

 If you do as you say and store your agar bulk style, then double boiler it to pour I have no doubt it would work if you were using a new sleeve of petris. 

 

What I am asking about is if it would be a good idea to pour it into half pint jars (which I use instead of petri dishes), which have been sitting on the shelf collecting dust and what ever, then cap with my lids that are in the same condition. 

 

Or would you sterilize the jars and lids just before pouring to ensure they are as clean as the agar?



#23 Myc

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Posted 15 March 2014 - 11:59 AM

 

 

What I am asking about is if it would be a good idea to pour it into half pint jars (which I use instead of petri dishes), which have been sitting on the shelf collecting dust and what ever, then cap with my lids that are in the same condition. 

 

Or would you sterilize the jars and lids just before pouring to ensure they are as clean as the agar?

 

 

You would, of course, want your sterile media to be stored in sterile vessels.

Just like pouring plates - they need to be sterile prior to receiving agar media.

 

Or if I have again mis-undertood,

There is an article here regarding pouring half-pint jars and then pressure cooking them. Poke-a-Plates?? I'll go look.

Scroll to post #27 in the discussion. Hippie3 weighs in with some of his experience:

https://mycotopia.ne...printing/page-2



#24 roscoe

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Posted 15 March 2014 - 12:14 PM

 

There is an article here regarding pouring half-pint jars and then pressure cooking them.

 

This is what I usually do, I was trying to combine your method and mine to save some time.  Thinking out loud I guess.

 

 

Just like pouring plates - they need to be sterile prior to receiving agar media.

 

I knew the answer before I asked the question, but was hoping with all hope you would drop another nugget and tell us you have pulled it off. 

 

As it stands all the time I would save by combining methods is the time it took to boil my potatoes/oats, and not the total time it took to make the agar since I would still have to double boiler the already made agar. 

 

Again thinking out loud. . . Thanks for playing along. . .



#25 BlackPeter17

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Posted 15 March 2014 - 05:19 PM

https://mycotopia.ne...ing-agar/page-2

post #23

 

"Ok say I wanted to make a liter of oat/yeast agar.  I would bring about 1300 mls of water (the extra is for steam loss) to a boil and add 80 grams of oats to the water and let boil for about 15 or 20 minutes. 

 

Then I would strain out the oat solids and pour the oat water back into my pot. 

 

Bring it back to a boil and add a couple of grams of nutritional or bakers yeast and slowly add (to prevent boil over) 20 grams of agar agar.  Stir it all very well until all of the agar has dissolved. 

 

Then I would put 20 mls of  the agar solution into each half pint jar using a 60 ml syringe.  I would then wait for the agar to cool down and solidify, so that I could easily wipe the excess moisture off of the sides of the jars.  Next put the lids on and PC for 45 minutes at 15 psi."  

 

So Id like to use brewers yeast, would I use the same amt as listed above?  and from what I read just make sure that its not more then 1/2 way full? just wondering ratios for the 1/4 pint jars.  Should I just make all the lids with self healing ports? should I PC the jars that have been previously used (BRF 1/2 pints) before I pour the agar?  and about how much time do I have after straining to get the jars filled before it solidifies, I have a 60cc syringe to work with for pouring?  do I cover while waiting to cool?  also how much potato would I substitute the oats with?  or should i just use oats?


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#26 roscoe

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Posted 15 March 2014 - 06:29 PM

 

So Id like to use brewers yeast, would I use the same amt as listed above?

 

I would.

 

 

and from what I read just make sure that its not more then 1/2 way full? just wondering ratios for the 1/4 pint jars.

 

I don't think it matters with agar to be honest.

 

 

Should I just make all the lids with self healing ports?

 

Yes with the addition of a breather, whether it be tyvek (which I prefer), polyfil, breathable tape of some sort, parafilm if you can figure a way to make it work for this application.

 

 

should I PC the jars that have been previously used (BRF 1/2 pints) before I pour the agar?

 

If you PC the agar in one container and then pour each jar after then yes you need to have your jars sterile.  This is why I like to "pour" my jars first then PC.

 

 

and about how much time do I have after straining to get the jars filled before it solidifies,

 

You will have more than enough time to pour your plates, just don't dilly dally around.  You don't have to rush it either, just take your time and work carefully.

 

 

I have a 60cc syringe to work with for pouring?

 

That is what I use. 

 

I did cut off the luer lock tip of the syringe to get a bigger hole to squirt from.  I did this so that I could have some lumps in my agar in case I wanted to leave my oats in, instead of straining them.  Also the agar will cool a little bit on the edges of the hole and narrow it a bit, making the syringe action not as smooth causing a bit of splashing and "after sex double stream" type action.

 

 

do I cover while waiting to cool?

 

Nope.

 

 

also how much potato would I substitute the oats with?

 

I just use one medium to large sized potato, no measuring or weighing it is not critical.

 

 

or should i just use oats?

 

6 of these, or a half dozen of the other. . .


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#27 BlackPeter17

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Posted 20 March 2014 - 12:59 PM

ok so I got the some tvac envelopes, do you have to use just the plain white part or is the whole envelope usable?  

 

I went with clear RTV versus the red as I was having difficulty finding the hole on a few lids last time.  will it work the same as red RTV? 

 

I ate the potatoes so All I have left is Bobs old fashioned rolled oats (wheat free, gluten free) ingredients: whole grain oats.  will this work with the brewers yeast or should I get different oats?  

 

if I make BRF jar lids with 4 SH ports and a tvac filter can I still use the dry verm barrier?  I just wondering because somebody said at one point no, however I feel like the moist rice/verm mix pressing against the tvac filter patch might get yucky.  


Edited by Direwolf13, 20 March 2014 - 12:59 PM.


#28 Microbe

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Posted 20 March 2014 - 01:31 PM

I prefer the clear RTV silicone. It is more flexible and will withstand temperatures in a PC. The red withstands higher temps but cures harder. I believe the clear withstands temperatures upto 650 degrees which more them suitable for making a self healing injector port. I don't use tyvek sonic any answer that one and I prefer synthetic filter disks.

#29 -=Zeus=-

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Posted 20 March 2014 - 02:42 PM

If I'm not mistaken, the clear RTV silicone is designed to be a sealant, while the red RTV is designed to be a gasket-maker.  I prefer the clear also. 

 

As far as the tyvek goes, if you use tyvek you really don't need a dry verm layer.  In fact, I didn't even use lids, I just used a double layer of tyvek and secured it with a jar band.  You can inject right through the tyvek and then place a piece of tape over the hole that is left.



#30 roscoe

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Posted 20 March 2014 - 06:12 PM

 

ok so I got the some tvac envelopes, do you have to use just the plain white part or is the whole envelope usable?

 

Any part.

 

 

I went with clear RTV versus the red as I was having difficulty finding the hole on a few lids last time.  will it work the same as red RTV?

 

Red is harder to find the hole but it lasts way longer than the clear.  So if you are making 100 lids and only want to make them once I'd go with red Don't forget to rough up the lid around your hole before you silicon to give it a "tooth" to hold on to.

 

For me the clear would start to pull out when I would try and withdraw the needle.  So I would have to hold the silicon down while I withdrew the needle. I could clearly see that the silicon was separated from the lid and only held in place because it was wider than the hole top and bottom.

 

 

I ate the potatoes so All I have left is Bobs old fashioned rolled oats (wheat free, gluten free) ingredients: whole grain oats.  will this work with the brewers yeast or should I get different oats?  

 

 

Oat is oats. 

 

 

if I make BRF jar lids with 4 SH ports and a tvac filter can I still use the dry verm barrier?

 

No verm needed.

 

 

I just wondering because somebody said at one point no, however I feel like the moist rice/verm mix pressing against the tvac filter patch might get yucky.

 

Your mix should not be in constant contact with your lid, if it is your jars are on the full side. Not that big of a problem with BRF, but bad practice for when you step up to grain.  You need some head space to shake grain jars.

 

~~~~~

 

As far as the tyvek goes, if you use tyvek you really don't need a dry verm layer.  In fact, I didn't even use lids, I just used a double layer of tyvek and secured it with a jar band.  You can inject right through the tyvek and then place a piece of tape over the hole that is left.

 

This will work in some conditions, but if your area is on the dry side I found the tops of my jars drying out long before they colonized.

 

In my local a 1\4 inch breather hole covered in tyvek works best. 


Edited by cyclenaut, 20 March 2014 - 06:16 PM.


#31 BlackPeter17

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Posted 20 March 2014 - 06:29 PM

Thanks for your thoroughness man!




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