What I Don't Understand About Slanting

[MHB]

Freezing is definitely the way I would go, there is lots of good information out there, you can store sensible sized (i.e. add to a starter) without any intermediate stepping up. Yeast isnt going to mutate. You can store for years. Very low risk of picking up infections.

MHB

 

[Nick JD]

-Guide to making a frozen yeast bank-
http://www.homebrewtalk.com/f13/guide-maki...ast-bank-35891/

Cheers for that. :beerbang:

 

[argon]

Here is a link to how it is done:

-Guide to making a frozen yeast bank-
http://www.homebrewtalk.com/f13/guide-maki...ast-bank-35891/

Freezing is definitely the way I would go, there is lots of good information out there, you can store sensible sized (i.e. add to a starter) without any intermediate stepping up. Yeast isnt going to mutate. You can store for years. Very low risk of picking up infections.

MHB

Sweet... and the added convenience for me is i have plenty of freezer space and very little fridge space... nice
:icon_cheers:

 

[[email protected]]

No probs Nick JD.

Does anyone know who is a good supplier for autoclavable vials?

Argon,

That is my thoughts as well. I have plenty of freezer room.

 

[drtomc]

I got a minimum chips 250 from ProSciTech http://www.proscitech.com.au/cataloguex/home.asp

T.

 

[pk.sax]

No probs Nick JD.

Does anyone know who is a good supplier for autoclavable vials?

Argon,

That is my thoughts as well. I have plenty of freezer room.

http://cgi.ebay.com.au/ws/eBayISAPI.dll?Vi...em=110548393424

I have these, quite good quality, an ebay solution anyway. Lids are plastic autoclavable screw tops as well.

 

[drsmurto]

I have been in contact with a US homebrewer who also has a PhD in microbiology and when I discussed the concept of slants and doing a yeast bank he said it is easier to manage a frozen yeast bank and that is what he does. It is the process I'm currently setting up to do. It is essentially the addition of glycerin to a water yeast blend and storing the vials in a freezer. The glycerin prevents any freezing and limited or no nutrient is present so mutation is limited compared the cryogenic storage processes the prefessionals use.

Here is a link to how it is done:

-Guide to making a frozen yeast bank-
http://www.homebrewtalk.com/f13/guide-maki...ast-bank-35891/

Cheers for the link, that's a great guide.

Any thoughts on using a no rinse sanitiser rather than a pressure cooker? I could boil the vials in my HLT for 15 mins prior to an orthophos acid rinse?

 

[TidalPete]

Any thoughts on using a no rinse sanitiser rather than a pressure cooker? I could boil the vials in my HLT for 15 mins prior to an orthophos acid rinse?

DS,
Boiled the crappers out of my autoclavable tubes (filled with sterilised water & the caps loosened sitting in a test tube rack) for a long time before getting a 2nd hand pressure cooker & experience has shown me that you need AT LEAST 30 minutes of good rolling boil to minimise the risk of tube infections but still had the odd failure. No sanitiser was used after the aforementioned. Pressure cooker definitely recommended.
Hope this helps.

TP

 

[outbreak]

I have purchased 50x 30ml sterile tubes with plastic caps, is there any point to autoclaving these?

 

[Nick JD]

Could the vials take 200C in the oven?

EDIT: oh, lids wouldn't regardless.

I s'pose the other thing is you wouldn't know you had a problem until you made a starter...

 

[TidalPete]

I have purchased 50x 30ml sterile tubes with plastic caps, is there any point to autoclaving these?

Not sure outbreak?
If they weren't specifically touted as autoclavable I might be hesitant.
Having said that, I pressure cook the sterile syringes that I use to split my smack packs ($0.50 a pop = tight arse but saving the world ) many times over with no problems until the syringe starts to get stick from over-use. Try one & see.

TP

 

[drsmurto]

I wonder if soaking in conc orthphos acid for 24-48 hours would be considered sterile. I use the vials to measure out the conc acid when diluting to no rinse strength so they have no problems with acid.

 

[np1962]

It is not only the vials that need to be sterile, the medium also requires sterilization hence the pressure cooking after adding the gelatine/agar + malt solution.
It needs to be sterile not just sanitary.
Nige

 

[drtomc]

Or the glycerine, if freezing.

T.

 

[Bribie G]

Yes for all we know the gelatine could be rife with salmonella and anthrax whatever

 

[drsmurto]

:icon_offtopic:

I understand the concept of a pressure cooker/autoclave to sterilise.

Washing with a dilute acid (orthphos) is classed as sanitary, is there a pH at which it becomes sterile? Are any of the bugs we are concerned about happy in the presence of concentrated orthphos acid (80+%)?

And yes, this still doesn't solve the issue of sterilising the medium and whilst vacuum distillation would it is a tad more labour intensive than forking out a few pesos for a pressure cooker.

 

[felten]

I'm sure if the concentration was high enough you could sterilise, but then it wouldn't be no rinse anymore

 

[Thirsty Boy]

I didn't read that particular guide to freezing yeast, so if itncovered this, sorry..

You need to be careful of using your frost free freezer for yeast frezing. Even under glycerol, yeast will suffer a reasonable mortality hit each time they are frozen and each time they are thawed... Yur frost free freezer will deliberately warm them up on a really quite regular basis, and each time, you are losing viability out of the stored sample.

So you either need an old fashioned non-frost free freezer for yeast freezing, or you need to take some steps to stop the freeze thaw cycle from happening to your yeast.

I froze yeast for a while, i find slants less trouble.

 

[[email protected]]

TB,

Yes the guide does. What is recommended is the vials are placed in a styrofoam box or small esky with gel ice packs inside to counter the fridge defrost cycle.

 

[Silo Ted]

because keeping yeast under liquid is just about the worst way to maintain a pure, viable, non-mutated version of the yeast you want to use. Whereas slanting is the next best option to cryogenic storage for exactly the same reasons.

Just back to this statement for a moment. If Whitelabs store their commercially packaged yeast under liquid for the intention of shipping to the world and sitting in a shop for 6 months or more, and expect it to be viable to the end user, that gives me faith that I can do the same thing at home with a relatively clean sample taken by top cropping a fermenting wort.

Or is it that any mutation on the strain has already occurred once it hits the beer?