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FrankRhizo
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Microwaving agar
#26456461 - 01/28/20 08:43 AM (4 years, 1 day ago) |
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When I microwave my 250ml media bottle, filled to the neck, the cap comes loose, obviously to let out steam. I believe it lets in contams. I usually don't melt it all the way. Is there a trick to this or do I just need to practice sterile technique?
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SFS96
AstroMan



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I normally tighten the fuck out of the lid to keep this from happening. It also helps if u melt it slowly, just for a min at a time. It also sounds like your bottle is too full.
-------------------- How I make and preserve tea
Consuming consumes a man That was never a purpose of life To only crave for material joys Is believing the lie - Mellow Mood
Edited by SFS96 (01/28/20 09:28 AM)
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FrankRhizo
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Re: Microwaving agar [Re: SFS96]
#26456511 - 01/28/20 09:33 AM (4 years, 1 day ago) |
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I literally just did it on a brand new 500ml bottle filled only to 250ml, that I sterilized Saturday and kept in a dedicated refrigerator. Nuked it 70 seconds looked and shook, another 35 seconds and it wasn't fully melted, but a audible hissing.
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SFS96
AstroMan



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Iv had it happen before and I was paranoid so I pressure cooked it again. It definitely helps if u tighten the fuck out of the lid.
-------------------- How I make and preserve tea
Consuming consumes a man That was never a purpose of life To only crave for material joys Is believing the lie - Mellow Mood
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FrankRhizo
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Re: Microwaving agar [Re: SFS96]
#26456522 - 01/28/20 09:42 AM (4 years, 1 day ago) |
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So dump it or sterilize again? I don't think I can tighten the lids anymore.
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SFS96
AstroMan



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Iโd sterilize again. Maybe just PC the day your going to poor agar so you donโt have to microwave. I was having the same issues but Iv stared cranking down on the lid extra hard and itโs working for me.
-------------------- How I make and preserve tea
Consuming consumes a man That was never a purpose of life To only crave for material joys Is believing the lie - Mellow Mood
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bodhisatta 
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Re: Microwaving agar [Re: SFS96]
#26456587 - 01/28/20 10:27 AM (4 years, 1 day ago) |
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You want the lid loose a quarter turn to microwave it otherwise the steam has no where to go
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345536345
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Exactly - that's bomb material otherwise. This is especially so if you weren't using quality glass. In regards to letting potential contams in, the heat of the agar is creating positive pressure and steam is being forced OUT of the bottle.
The only time I could see a potential issue would be opening the bottle direct from a cold fridge which might draw some air in (same principle, but in reverse) so letting it come to room temp first should essentially negate that. If you're still concerned take a paper towel wet with ISO and wrap around the neck when opening cold to serve as a "filter".
Beyond that when you heat the agar it needs to get to around 180* to melt anyway and will take a little bit to cool down to pouring temp so any potential invaders would likely be pasteurized.
Personally I almost always take it out of the fridge, crack the cap open a bit, hear a hiss (get slightly concerned) and then proceed along my way. I've yet to get a contam related to this. I tend to pour a bunch of plates and keep clean ones around (wrapped w/ parafilm) for a long while until I finally need them and (knock on wood) they've always stayed clean.
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FrankRhizo
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Thank you!
Edited by FrankRhizo (01/28/20 10:46 AM)
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345536345
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Forgot to add - on a 500ml bottle I never fill over 400ml. You need some head space to allow for bubbling up agar which tends to happen if heating too fast and you don't want it spilling out / dripping down the sides. Once cooled that spillage / agar slop could be a contam vector.
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Camera93
We got dicks like Jesus



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arent the GL45 caps designed to vent and vac properly without having to purposefully loosen the cap?
Quoting Caps here
Quote:
Caps McGee said: If they're proper lids (gl45) It's not necessary... They'll vent and vac without issue
Quote:
Caps McGee said: I dont tighten them with the Vulcan death grip, but not going out of my way to leave them loose: it's designed for the very purpose
But since I seen that posted, I tried to look it up myself and seen this tidbit on it
I recently did a bottle in the microwave that was about half full and I didnt loosen the cap. It boiled but didnt rise up the media bottle and spill over maybe I just stopped it in time?
-------------------- All I need are some tasty waves, a cool buzz, and Iโm fine. Whatever you decide wonโt really impact our survival Close your eyes, and do the best that you can
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345536345
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Re: Microwaving agar [Re: Camera93]
#26456682 - 01/28/20 11:31 AM (4 years, 1 day ago) |
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I'd be interested to see any detail around the GL45 caps being specifically designed for vent and vac. I didn't find anything in a brief search on the topic and it seems Corning sells GL45 caps specifically for venting and sterile air exchange via a PTFE liner. Not saying that Caps is wrong, just that it's news to me and I can't seem to confirm it.
As for the bubbling but not boiling over thing if the cap is on tight it's go nowhere to go so it's not going to spill out. Steam pressure will build however inside the bottle which is of concern. Heating agar in the microwave is a balancing act. I typically run mine for around 9 minutes on power level 4. That seems to be a good setting to avoid any boilovers but I still keep an eye on it. Your microwave will be different so test to find out what works for yours.
Almost all microwaves (beside some fancy new ones) have power levels that simply turn on and off the full power mode during cook time. So power level 10 is constant full power during cook time. Power level 5 oscillates between half on and half off. You'll see the boiling start up when it's running then subside when it's off when using a lower power during the cook time.
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Sockadin



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Wait we are using a microwave now? I'm so confused, what types of bottles are we using? I just use a 500ml wine bottle and poor all of it into plates in 1 sitting after PC run and then wrap my plates with Parafilm... I am missing something, is this microwave used for any in used agar in the OG bottle?
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Camera93
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Re: Microwaving agar [Re: Sockadin]
#26456852 - 01/28/20 01:19 PM (4 years, 1 day ago) |
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Quote:
Sockadin said: Wait we are using a microwave now? I'm so confused, what types of bottles are we using? I just use a 500ml wine bottle and poor all of it into plates in 1 sitting after PC run and then wrap my plates with Parafilm... I am missing something, is this microwave used for any in used agar in the OG bottle?
I should have stated I am using a media bottle these
-------------------- All I need are some tasty waves, a cool buzz, and Iโm fine. Whatever you decide wonโt really impact our survival Close your eyes, and do the best that you can
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gizmo1



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Re: Microwaving agar [Re: Sockadin]
#26456870 - 01/28/20 01:33 PM (4 years, 1 day ago) |
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Quote:
Sockadin said: Wait we are using a microwave now? I'm so confused, what types of bottles are we using? I just use a 500ml wine bottle and poor all of it into plates in 1 sitting after PC run and then wrap my plates with Parafilm... I am missing something, is this microwave used for any in used agar in the OG bottle?
The microwave is only used to re melt pre sterilized agar not to sterilize it. In my case I just use the kitchen microwave dont have a dedicated microwave. The bottles being mentioned are pyrex or generic media bottles made specifically for lab use. Try searching pyrex media bottle on Amazon or google to get an example of the bottles alot of us use now.
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Edited by gizmo1 (01/28/20 01:34 PM)
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Sockadin



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Re: Microwaving agar [Re: gizmo1]
#26456879 - 01/28/20 01:41 PM (4 years, 1 day ago) |
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Damn I want new bottles. The wine bottles are very tall even for my AA and I don't link the weight of them when pouring.
Can you set the bottles in a bottle warmer instead of a microwave to remelt the agar slowly?
Edited by Sockadin (01/28/20 01:43 PM)
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gizmo1



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Re: Microwaving agar [Re: gizmo1]
#26456900 - 01/28/20 01:53 PM (4 years, 1 day ago) |
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If you go with knock offs make sure you don't get the para-wish bullshit. They are a little cheaper but I think they are the cadamada returns or ones that didnt make the cut. Alot of reviewers said the media bottles came with agar residue already inside them or they came dirty and used. Alot of people also said that the no drip rings didnt fit and would fall off even after replacing with a real gl45 cap and ring. The cadamada ones have some bad reviews also but reading through them most of them can be chalked up to user error and overall pickyness. Some people were obviously expecting the best for the least amount of money. I've got 5 knockoff ones 3 of the 5 have been THOROUGHLY tested and are fine for my use. They do however have some blemishes and as with most scientific tools the marking are estimates not meant to be precise measuring tools like a graduated cylinder. Lastly the name brand ones. I haven't really tried any of them but I've used plenty of pyrex and I know you can't really go wrong with pyrex. They aren't much more about 15 bucks a bottle and I'm sure they will last a very long time so the price is justified. Sorry if I'm getting a little off the original topic just though this may help anyone looking to get a new media bottle.
-------------------- Trade List ๐๐๐ 6 hole Mini Monos
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FrankRhizo
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Re: Microwaving agar [Re: gizmo1]
#26456932 - 01/28/20 02:13 PM (4 years, 1 day ago) |
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Quote:
gizmo1 said: If you go with knock offs make sure you don't get the para-wish bullshit. They are a little cheaper but I think they are the cadamada returns or ones that didnt make the cut. Alot of reviewers said the media bottles came with agar residue already inside them or they came dirty and used. Alot of people also said that the no drip rings didnt fit and would fall off even after replacing with a real gl45 cap and ring. The cadamada ones have some bad reviews also but reading through them most of them can be chalked up to user error and overall pickyness. Some people were obviously expecting the best for the least amount of money. I've got 5 knockoff ones 3 of the 5 have been THOROUGHLY tested and are fine for my use. They do however have some blemishes and as with most scientific tools the marking are estimates not meant to be precise measuring tools like a graduated cylinder. Lastly the name brand ones. I haven't really tried any of them but I've used plenty of pyrex and I know you can't really go wrong with pyrex. They aren't much more about 15 bucks a bottle and I'm sure they will last a very long time so the price is justified. Sorry if I'm getting a little off the original topic just though this may help anyone looking to get a new media bottle.
It maybe my issue. I got 3 500ml for like $15-20 American. Same type pretty much as my 250ml media bottles.
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gizmo1



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I dont know. When you say the bottle was filled to the neck what exactly do you mean can you post a pic sounds like overfilling. I wouldn't be scared of the microwave I've done it a bunch of times and am yet to see any contams because of it. I always the the cap loosened. I also freeze my agar and go straight from microwave to the freezer most of the time. I prefer to wait but you know how life is sometimes I'm just too busy. Have some faith in the process either that or just prep and pressure cook your agar only when you are ready to use it. Any reason why you chose 250ml bottles? I have them also but my 500ml ones dont fit in the microwave and I use less agar now that I switched to 60mm petris.
-------------------- Trade List ๐๐๐ 6 hole Mini Monos
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Sockadin



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Re: Microwaving agar [Re: gizmo1]
#26456967 - 01/28/20 02:41 PM (4 years, 1 day ago) |
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I just got my case 500 of 100mm Pettis and now I'm like
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gizmo1



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Re: Microwaving agar [Re: Sockadin]
#26457027 - 01/28/20 03:08 PM (4 years, 1 day ago) |
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Why? Lol.
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FrankRhizo
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Re: Microwaving agar [Re: gizmo1]
#26457099 - 01/28/20 03:41 PM (4 years, 1 day ago) |
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Quote:
gizmo1 said: I dont know. When you say the bottle was filled to the neck what exactly do you mean can you post a pic sounds like overfilling. I wouldn't be scared of the microwave I've done it a bunch of times and am yet to see any contams because of it. I always the the cap loosened. I also freeze my agar and go straight from microwave to the freezer most of the time. I prefer to wait but you know how life is sometimes I'm just too busy. Have some faith in the process either that or just prep and pressure cook your agar only when you are ready to use it. Any reason why you chose 250ml bottles? I have them also but my 500ml ones dont fit in the microwave and I use less agar now that I switched to 60mm petris.
I also have 60mm petris, 10 a sleeve. The 250 does 2 sleeves perfectly. I'm just trying to use my time, money, and energy efficiently. Instead of 4 PC sessions I could do 1. I don't have boil over problems cause I stick the 250s in a wide mouth pint jar.
Edited by FrankRhizo (01/28/20 03:43 PM)
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FrankRhizo
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Edited by FrankRhizo (01/28/20 03:46 PM)
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gizmo1



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Yea that's fine it's not overfilled at all. Like I said just have faith in the process crack the lid and microwave it. I'm sure it'll be fine I do it all the time then walk with the hot bottle across a dirty house with dirty carpet and mold. Straight into my lab where I let it cool in a SAB.
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Sockadin



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Re: Microwaving agar [Re: gizmo1]
#26457293 - 01/28/20 05:35 PM (4 years, 1 day ago) |
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Cause you know me, we been growing together for years and I don't know what the fuck im doing after 10 years on this site.
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gizmo1



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Re: Microwaving agar [Re: Sockadin]
#26457312 - 01/28/20 05:46 PM (4 years, 1 day ago) |
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Quote:
Sockadin said: Cause you know me, we been growing together for years and I don't know what the fuck im doing after 10 years on this site.
Nothing wrong with 100mm petris though I like them I put 3 transfer on a single plate.
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345536345
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Re: Microwaving agar [Re: Sockadin]
#26457395 - 01/28/20 06:34 PM (4 years, 1 day ago) |
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Quote:
Sockadin said: I just got my case 500 of 100mm Pettis and now I'm like 
I actually prefer the 100mm dishes. You can drop three tissue samples if you wish on a plate and have room to see decent growth. If you drop one wedge on you can let it run for a solid week before having to transfer. I appreciate the extra flexibility and time if I need it. I do 400ml batches of agar which equates to 10 100mm dishes poured relatively thick (my preference) with a few ml to spare. Agar is cheap.
For your water bath question above you absolutely can. Just need to get it above say 190 or so until the agar fully melts and then drop it down to pouring temp. I have a sous vide stick that I love for that reason exactly. I don't need to time it just right. Just stick it in the water bath and it's always ready at the perfect temp when I want it. Labs employ the same approach as I understand it.
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Sockadin



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Thats dope. I do not have a Sous Vide stick, but I also love to cook. Might be worth the investment. I just watched an episode of Munchies with matty matheson and I thought I remember he used one for making some crazy shit.
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gizmo1



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Water baths work fine but take for fucking ever to melt the agar and I'm impatient so I go with the microwave.
Quote:
Sockadin said: Thats dope. I do not have a Sous Vide stick, but I also love to cook. Might be worth the investment. I just watched an episode of Munchies with matty matheson and I thought I remember he used one for making some crazy shit.
I want one for cooking a perfect steak.
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345536345
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Re: Microwaving agar [Re: gizmo1]
#26457454 - 01/28/20 07:08 PM (4 years, 1 day ago) |
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LOL! Yeah I usually microwave the agar to melt and then put into the water bath to bring down to, and hold temp for as long as I need. This way I go about my day and then when I'm ready I'm good to go.
It's also perfect for pasteurizing casing without having to babysit the stove.
In the meantime it's killer for getting meats perfectly cooked. I'm getting hungry now just thinking about it!
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Sockadin



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I dont own a microwave, you know..... Cancer and shit.
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