Pressure Cooker For Steralising Vials

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bowie in space

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I recently purchased some plastic screw top test tubes/vials from the BribieG mega garage clearance sale. So, I've been reading up on steralising plastic vials with gelatine or agar agar mixtures to enable me to freeze yeast or make slants. I still haven't decided weather I'll freeze a gelatine/yeast solution or go down the slanty slippery slope freezing wort and innocuating with a loop, etc etc.

Anywho, my question is probably simple to answer. What I don't know about is the pressure cooker part. I have a slow cooker, can I use this? How is a slow cooker different from a pressure cooker? Sorry if the question seems basic, but I need to ask.

Cheers,
Bowie
 
While pressure cookers and slow cookers can (sort of) achieve similar results when it comes to cooking food, the same isn't true for sterilisation.

Pressure cookers use an increase in pressure inside the vessel to increase the boiling point of water - normally 15 psi which gives a 120ish degree boiling point.

Slow cooker's work by heating the contents to 80-90 degrees.

Sterilisation will take a lot longer (just like the food, actually) at 80 degree's than it will at 120.

The thing is - a normal pot on your stove will get a nice 100 degree pot of water going - it's not going to sterilise as fast as a pressure cooker - but will be a lot better than the slow cooker.
 
I recently purchased some plastic screw top test tubes/vials from the BribieG mega garage clearance sale. So, I've been reading up on steralising plastic vials with gelatine or agar agar mixtures to enable me to freeze yeast or make slants. I still haven't decided weather I'll freeze a gelatine/yeast solution or go down the slanty slippery slope freezing wort and innocuating with a loop, etc etc.

Anywho, my question is probably simple to answer. What I don't know about is the pressure cooker part. I have a slow cooker, can I use this? How is a slow cooker different from a pressure cooker? Sorry if the question seems basic, but I need to ask.

Cheers,
Bowie

I used to use a pressure cooker all the time to do steri work on mediums and agar agar work. Gets the job done. Got one of the italian ones at victoriasbasement, big, solid, good seal.
 
Thanks for the replies. Looks like I'll have to invest in a pressure cooker. Might try and see if Aldi have any on special. Don't fancy paying more than $100.
 
Nice link there Jim, have you (or anyone else) tried steralising this way? Can't seem to think why it wouldn't work. It would definately fit a number of the vials I have. I'd appreciate any feedback.

Cheers
Bowie
 
Further to my comments earlier about temps and what's going on - there's lots of info here:
http://en.wikipedia.org/wiki/Sterilization_(microbiology)

It says that "Boiling in water for fifteen minutes will kill most vegetative bacteria and inactivate viruses, but boiling is ineffective against prions and many bacterial and fungal spores; therefore boiling is unsuitable for sterilization."

So I take back my comment about using a boiling pot of water on the stove, for proper sterilization. It adds further wait to my comments about a slow cooker being even worse though!
 
Sorry bowie, I've only used them for babies bottles etc. worked fine for them.

Cheers SJ
 
Bowie, also keep an eye for those microwavable babies dummy/bottle sterilisers. They will do the same job (5mins in the micro) and will def come in under your $100 budget.

http://www.ebay.com.au/itm/BNIB-Avent-Phil...5#ht_3287wt_989

This is new, but second hand is even cheaper.

Cheers SJ

"effective sterilization for 24 hours" - is that going to be sufficient for long term storage? Unsure. Certainly would be easier and safer thx a pressure cooker.
 
"effective sterilization for 24 hours" - is that going to be sufficient for long term storage? Unsure. Certainly would be easier and safer thx a pressure cooker.

That's 24 hours if you leave the stuff in the sterilizer with the lid on. Usually you wouldn't do that with vials, you would take them out straight away, fill and cap.


Personally I don't like to mess around with pressure cookers or boiling water. I bought a bag of 100 vials for about $15 a while ago, they came in sterile condition. I just open fill and close, and when I have used the content I might keep them, but will probably just by a new bag eventually and chuck the old ones out.
Of course this only applies to filling vials with yeast, if you want to make slants then you might not get around some other form of sterilisation like a pressure cooker or auto clave.
 
That's 24 hours if you leave the stuff in the sterilizer with the lid on. Usually you wouldn't do that with vials, you would take them out straight away, fill and cap.


Personally I don't like to mess around with pressure cookers or boiling water. I bought a bag of 100 vials for about $15 a while ago, they came in sterile condition. I just open fill and close, and when I have used the content I might keep them, but will probably just by a new bag eventually and chuck the old ones out.
Of course this only applies to filling vials with yeast, if you want to make slants then you might not get around some other form of sterilisation like a pressure cooker or auto clave.

Where you get the vial packs from? I am using urine sample jars which are a dollar from the pharmacy.
 
Oh and I suppose I was wondering if those baby sterilisers really sterilise properly (as well as a pressure cooker) or just to the level that is sufficient for its intended purpose.
 
Where you get the vial packs from? I am using urine sample jars which are a dollar from the pharmacy.

From Livingstone. Needs a bit of searching in their lab stuff though to find the right ones. Mine are 10ml clear with yellow screw top, sterile.
 
I have borrowed my baby's bottle steriliser for yeast vials. Works great, fast and effective. You just need to make sure your vials are a suitable plastic for this treatment or you'll warp them.
 
How about steralising vials in an erlenmeyer flask on the stove? I was reading Tony's post about splitting wyeast packs and he boils about four whitelabs vials in an erlenmeyer flask. Now that I've considered it, mucking around with a pressure cooker seems a little unsafe. I'm still keen on the freezing with glycerine/agar agar idea.

Any thoughts?
 
I guess now the next step would be, how much exactly would a box of sterile single use vials cost? I get the feeling around $100 would be many.
 
How about steralising vials in an erlenmeyer flask on the stove? I was reading Tony's post about splitting wyeast packs and he boils about four whitelabs vials in an erlenmeyer flask. Now that I've considered it, mucking around with a pressure cooker seems a little unsafe.

Like I said earlier mate "boiling is ineffective against prions and many bacterial and fungal spores; therefore boiling is unsuitable for sterilization". There is a huge difference between water boiling at 100 degrees at normal pressure and water boiling at 130 degree's under higher pressure.

Modern pressure cookers are not unsafe in any way - they have safety blow off valves that are connected to a lid lock - there's no way you can open the lid while the thing is still under pressure. I suppose if the thing was forgotten about with the heat on ludicrous speed, it might rupture and asplode - but you'd have to be seriously negligent with it for that to happen.
 
Like I said earlier mate "boiling is ineffective against prions and many bacterial and fungal spores; therefore boiling is unsuitable for sterilization". There is a huge difference between water boiling at 100 degrees at normal pressure and water boiling at 130 degree's under higher pressure.

Modern pressure cookers are not unsafe in any way - they have safety blow off valves that are connected to a lid lock - there's no way you can open the lid while the thing is still under pressure. I suppose if the thing was forgotten about with the heat on ludicrous speed, it might rupture and asplode - but you'd have to be seriously negligent with it for that to happen.

There are decent "how to use a pressure cooker" guides on utube. Usually about jar sterilisation for jam making.
 
Like I said earlier mate "boiling is ineffective against prions and many bacterial and fungal spores; therefore boiling is unsuitable for sterilization". There is a huge difference between water boiling at 100 degrees at normal pressure and water boiling at 130 degree's under higher pressure.

Modern pressure cookers are not unsafe in any way - they have safety blow off valves that are connected to a lid lock - there's no way you can open the lid while the thing is still under pressure. I suppose if the thing was forgotten about with the heat on ludicrous speed, it might rupture and asplode - but you'd have to be seriously negligent with it for that to happen.

I guess I'm trying to kill two birds...

I want to get an erlenmeyer flask anyway and thought it would be suitable for both steralising and making starters.
 
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