Agar won't solidify

nyi · 05-23-09, 05:18

Hi everyone! Second time happened something strange in my agar. When I prepare agar, I pour plates and what's left I pour into a clean jar. When I need to pour new plates, I scrape the agar and place it in the plates. I sterilize the plates and the jar. On top of the jar I pour some peroxide (with the first batch I used 3%, now older 30%).

First few serilization worked great and then, randomly it just do not solidify. First batch was made from a nutrient drink and this second was 1,5% agar, 3% malt, 0,5% dextrose, 2% salt. What do you think about this?

susu · 05-23-09, 08:33

befor pouring u have to mix the solution a little otherwise u get some soft plates and some hard ones ,because the agar will sink to the bottom of the jar
that maybe the problem

i never use salt in my medium,maybe thats not good?

nyi · 05-23-09, 15:32

No. The agar in jar was already solidified. I stir enought. The liquid is absolutely like water with nutes added, just cloudy, like agar, no viscosity. It looks as if the agar was destroyed by pressure cooking. I sterilized another batch of plates today along with the jar, from which I took the agar.

This time I placed the jar in hot water bath and sucked the liquefied agar with syringe. Agar in plates solidified, but the jar in jar didn't. I don't understand, they were sterilized together. It looks as if the agar in the was destroyed in the process of pressure cooking.

I better fall back to making just so much agar I will need for every pouring right before.

joystik · 05-25-09, 15:34

I suggest not to re-use already cooked agar.

nyi · 05-25-09, 18:24

Great! That solved everithig, except the reson, why I tried to reuse cooked agar

joystik · 05-26-09, 11:02

You may want to check for PH.

Quote:

The solidification of the agar within any growth media (GM) is pH-dependent, with an optimal range between 5.4-5.7.

JoY.

nyi · 05-26-09, 13:53

Great, that's what I'm looking for. Next time, hopefully today, I'll do again a little bit more agar and I'll pressure cook it until it stops solidifying. Then I'll check pH and hopefully after adjusting, it'll work again. Thanks!

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05-23-09, 05:18	#1 (permalink)
nyi Mycophage Join Date: Dec 2008 Posts: 104	Agar won't solidify Hi everyone! Second time happened something strange in my agar. When I prepare agar, I pour plates and what's left I pour into a clean jar. When I need to pour new plates, I scrape the agar and place it in the plates. I sterilize the plates and the jar. On top of the jar I pour some peroxide (with the first batch I used 3%, now older 30%). First few serilization worked great and then, randomly it just do not solidify. First batch was made from a nutrient drink and this second was 1,5% agar, 3% malt, 0,5% dextrose, 2% salt. What do you think about this? __________________ We're animals... nature just decided, that the next global disaster shouldn't be an big fat asteroid... it should be an animal.

05-23-09, 15:32	#3 (permalink)
nyi Mycophage Join Date: Dec 2008 Posts: 104	No. The agar in jar was already solidified. I stir enought. The liquid is absolutely like water with nutes added, just cloudy, like agar, no viscosity. It looks as if the agar was destroyed by pressure cooking. I sterilized another batch of plates today along with the jar, from which I took the agar. This time I placed the jar in hot water bath and sucked the liquefied agar with syringe. Agar in plates solidified, but the jar in jar didn't. I don't understand, they were sterilized together. It looks as if the agar in the was destroyed in the process of pressure cooking. I better fall back to making just so much agar I will need for every pouring right before. __________________ We're animals... nature just decided, that the next global disaster shouldn't be an big fat asteroid... it should be an animal.

05-25-09, 18:24	#5 (permalink)
nyi Mycophage Join Date: Dec 2008 Posts: 104	Great! That solved everithig, except the reson, why I tried to reuse cooked agar __________________ We're animals... nature just decided, that the next global disaster shouldn't be an big fat asteroid... it should be an animal.

05-26-09, 13:53	#7 (permalink)
nyi Mycophage Join Date: Dec 2008 Posts: 104	Great, that's what I'm looking for. Next time, hopefully today, I'll do again a little bit more agar and I'll pressure cook it until it stops solidifying. Then I'll check pH and hopefully after adjusting, it'll work again. Thanks! __________________ We're animals... nature just decided, that the next global disaster shouldn't be an big fat asteroid... it should be an animal.

05-23-09, 08:33	#2 (permalink)
susu Mycophiliac Join Date: Mar 2007 Posts: 64	befor pouring u have to mix the solution a little otherwise u get some soft plates and some hard ones ,because the agar will sink to the bottom of the jar that maybe the problem i never use salt in my medium,maybe thats not good?

05-25-09, 15:34	#4 (permalink)
joystik Mycotopiate Join Date: Nov 2006 Posts: 455	I suggest not to re-use already cooked agar.

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