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naturalistic123



Registered: 02/18/18
Posts: 891
Last seen: 4 months, 12 days
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Agar boiling over
#25193199 - 05/09/18 09:42 AM (6 years, 8 months ago) |
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Hey everyone, i'm hoping someone may have encountered this before and what exactly is causing this, or at least how to get it to stop.
I have a small, electric 6 qt pressure cooker, and I've just recently begun trying to get into agar. I have Bod's special media bottle, and am using the BRF agar formula. I start off by boiling 400ml of water, then putting the dry ingredients in the bottle, then pour the water in, shake it, then loosen the cap and wrap with foil, then into the PC. Since the PC I have is small, I have to rig the bottle tilted just a bit, but not to where it should be tipping out. I put about an inch of water in, then pc for 30 mins.
The problem is, the solution keeps boiling out of the media bottle. Its happened twice now, and it gets to be a big nasty hard to clean mess. The first time I figured I had too much water. I even stopped before I actually put the weight down, and opened the pc, to make sure it was okay, and it was fine.
The only other thing I haven't tried yet....When the PC is done cooking, I vent it and push the weight down, and let all the steam come out quickly. Could this somehow be making the solution in the bottle boil all of sudden?
Thanks for any and all help, I really want to get this right so I can continue in this wonderful hobby.
-------------------- Ὡς οὖν εἴπεν αὐτοῖς ὅτι Ἐγώ εἰμι, ἀπῆλθον εἰς τὰ ὀπίσω, καὶ ἔπεσον χαμαί.
Edited by naturalistic123 (05/10/18 08:50 AM)
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kayo
Stranger


Registered: 01/16/18
Posts: 300
Loc: Ul'dah
Last seen: 5 years, 3 months
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Quote:
naturalistic123 said: When the PC is done cooking, I vent it and push the weight down, and let all the steam come out quickly. Could this somehow be making the solution in the bottle boil all of sudden?
Yup, that is exactly what is happening. Depressurizing the PC before it cools below boiling temps (212F) will cause it to boil. I have exactly the same PC and do the tilt thing too, except once its off I leave it alone for 30 minutes, no boil over as of yet.
I also did under 350mL not 400mL. 400mL was too close to the cap for comfort since itll still boil a little from temperature and pressure fluctuations.
Edited by kayo (05/09/18 10:16 AM)
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naturalistic123



Registered: 02/18/18
Posts: 891
Last seen: 4 months, 12 days
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Re: Agar help [Re: kayo]
#25193241 - 05/09/18 10:23 AM (6 years, 8 months ago) |
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Thanks for your help Kayo, tonight I will try this out, after I clean all the gelatin and brf from my PC and media bottle. I will also take your advice on the 350ml, could I ask you about how many petris this amount would make?
-------------------- Ὡς οὖν εἴπεν αὐτοῖς ὅτι Ἐγώ εἰμι, ἀπῆλθον εἰς τὰ ὀπίσω, καὶ ἔπεσον χαμαί.
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kayo
Stranger


Registered: 01/16/18
Posts: 300
Loc: Ul'dah
Last seen: 5 years, 3 months
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Well I havent used an entire bottle yet. I only make about 2-3 75mm glass dishes at a time. I was using oat water before and PC'd the bottle before pouring so they got "dirty" after a few sessions and id make another.
Typically though its about ~20 standard plastic 90-100mm dishes per 500mL so expect around 15 plates I guess. This of course all depends on how large your plates and how high you like to fill it.
Edited by kayo (05/09/18 11:07 AM)
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naturalistic123



Registered: 02/18/18
Posts: 891
Last seen: 4 months, 12 days
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Re: Agar help [Re: kayo]
#25193318 - 05/09/18 11:11 AM (6 years, 8 months ago) |
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Agar seems really intense and worrying to me. I feel that way about everything I do if I haven't done it before though, so maybe its just that. I just wonder about all the small variables, like after I take the media bottle out of the PC and down to the work area, do I need to wipe everything with alchohol before it goes in the SAB? Also, I removed the wrap from my petris outside of my SAB and I think they probably got dirty, now they're just sitting in the SAB because I didn't properly make the agar, and after I make them, do I just let them sit in the SAB, just on and on. It's really freakin stressful. Hopefully after its done a few times I can breathe easier.
Just thinking out loud, thanks for your help Kayo.
-------------------- Ὡς οὖν εἴπεν αὐτοῖς ὅτι Ἐγώ εἰμι, ἀπῆλθον εἰς τὰ ὀπίσω, καὶ ἔπεσον χαμαί.
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Mycolorado
Hobbyist


Registered: 07/23/16
Posts: 8,579
Loc: Interdimensional Bootcamp
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Are you going to be able to try again if all or at least some things fail on this attempt?
In the future, remove the petris from the sleeve in the SAB. However, as long as the individual dishes didin't open up, you should be good go.
This is all a learning experience and you're not likely to master anything on the first run, so take it easy and don't get stressed out. 
Edited by Mycolorado (05/09/18 11:36 AM)
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naturalistic123



Registered: 02/18/18
Posts: 891
Last seen: 4 months, 12 days
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Thanks for the good words, and yes ive got enough supplies to fail many times over!
-------------------- Ὡς οὖν εἴπεν αὐτοῖς ὅτι Ἐγώ εἰμι, ἀπῆλθον εἰς τὰ ὀπίσω, καὶ ἔπεσον χαμαί.
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
Posts: 61,916
Loc: Milky way
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At pressure the water boiles at a higher temperature. We use this to speed up sterilization.
At 15psi your pressure cooker is 250F or 121C At 0psi (what you and i live in) water boils at 212F
If you vent the steam at the end of cooking all the water and agar will EXPLOSIVELY boil.
Your best bet is to add MORE water to the cooker. And let it cool down AS SLOW AS POSSIBLE.
Your bottle of agar is in the center of the cooker. Naturally it will stay hot the longest. The cooker itself has contact with the air surrounding it so it cools down first.
If your agar is hotter than the water around it it will boil over. More water in the cooker acts as insulation so your agar doesn't boil over but gently cools to below 212F.
My agar tek also explains all of this in detail. Its comprehensive so to avoid all mishaps along the road.
Agar should be the opposite of intense. Its where you can fail and where you catch fail before it ruins hard work. Its pouring jello into small trays.
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bodhisatta 
Smurf real estate agent


Registered: 04/30/13
Posts: 61,916
Loc: Milky way
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Quote:
naturalistic123 said: Thanks for your help Kayo, tonight I will try this out, after I clean all the gelatin and brf from my PC and media bottle. I will also take your advice on the 350ml, could I ask you about how many petris this amount would make?
You can put 10-30ml in a plate but 20 is pretty good. At 10ml you may have to swirl the dish to coat the entire bottom. This is useful with very expensive media like the kind used to differentiate wild yeast from brewing yeast its like 4-5 dollars a plate just in media cost
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naturalistic123



Registered: 02/18/18
Posts: 891
Last seen: 4 months, 12 days
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Thanks Bod, this pretty much answers all my questions. I've read your tek many times over, but i dont think i read the whole thing, just the beggining parts, im sorry i missed it, i guess i just get caught up in it. Thank you so much for the help! Ill post any success in this thread for future people, and maybe rename the thread to help others finding this specifically (if its possible to rename)
-------------------- Ὡς οὖν εἴπεν αὐτοῖς ὅτι Ἐγώ εἰμι, ἀπῆλθον εἰς τὰ ὀπίσω, καὶ ἔπεσον χαμαί.
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naturalistic123



Registered: 02/18/18
Posts: 891
Last seen: 4 months, 12 days
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- Update -
My agar was boiling over inside of my media bottle when I pressure cooked it because I was venting my pressure cooker of all steam as soon as the cycle was over. Last night I mixed up 400 ML of agar in Bod's special 500ml media bottle, and rigged it up in my pc (because it's so small, I have to tilt it slightly and rig it up on balled up aluminum foil). After a thirty minute cycle I opened it up after it had fully vented on its own and, voila, no boil over.
The lesson to be learned from this thread, and the answer to the subject of it is :DO NOT TRY TO VENT YOUR PRESSURE COOKER AFTER ITS DONE.
Thank you to everyone who helped.
-------------------- Ὡς οὖν εἴπεν αὐτοῖς ὅτι Ἐγώ εἰμι, ἀπῆλθον εἰς τὰ ὀπίσω, καὶ ἔπεσον χαμαί.
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Mad Season
hookers and blackjack



Registered: 09/16/12
Posts: 12,666
Loc: Canada
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xD if I didn't have a working knowledge of pressure and boiling temps, I guarantee I would have made the same mistake. Lesson learned
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