Washing and storing yeast using chlorine dioxide

[masterbrewer]

Hi all,

So you’ve just made a fantastic beer with some exotic imported yeast strain. How do I save this yeast for future use?

Here is my procedure for washing and storing yeast.

First, a few things to remember:
1) Work clean - as close as possible to sterile.
2) Everything must be as cold as possible
3) Share your slurries!!

For 2L slurry (slurry only, no beer), I will take 5L of boiled & cooled water, 70ml chlorine dioxide and enough phosphoric acid to adjust ph to 3.0. Everything must be as cold as possible. Add the slurry to the water & chlorine dioxide, give it a good mix up, strain through a sanitised stainless steel sieve and let it stand overnight in the fridge. Next morning pour off the dirty water on top of the slurry, pour over 2L boiled & cooled water, mix and pour into 4 x sanitised 1L PET bottles - 4 slurries good for using, storing or sharing.

You can store your yeast in this state at 2C for up to 6 months, but I recommend you make a starter if you stored your slurry for longer than a few weeks. This will help your yeasty friends to gently come out of hibernation.

Cheers,

[tweedronk]

Hallo

THX that will help a lot.
Cheers

Riaan

[Silenus]

Interesting Andre - thanks.
I assume the chlorine dioxide is to avoid infection ?

My method is as follows :
1.) boil 1X 3kg jar and lid and 6X 200ml jars and lids for 15 minutes.
2.) remove jars (full of boiled water) and lids with tongs
3.) put closed full jars into fridge overnight
4.) pour water from all jars onto yeast cake in primary.
5.) stand for 20mins.
6.) pour liquid from primary into 3kg jar - making sure to get no settlement matter into jar.
7.) stand for 20mins
8.) pour liquid from 3kg into small jars and refridgerate.

When I need to make a starter I take a jar from the fridge, pour off the beer ontop of the yeast cake and pitch the yeast into my starter.

[masterbrewer]

(27-11-2009 02:31 PM)Silenus Wrote:  Interesting Andre - thanks.
I assume the chlorine dioxide is to avoid infection ?

Yes, the chlorine dioxide will kill all (or as close as dammit to all) bacteria that might be present in your slurry. The low ph help to make the yeast less floculant, giving the chlorine dioxide beter access to all the yeast cells.

Your method described, also know as yeast rinsing, is very effective in removing trub and dead yeast cells, but won't kill any bacteria.

[Silenus]

Im going to start adjusting pH.
Does chlorine dioxide not have any negative effects on the yeast ?

(27-11-2009 03:04 PM)masterbrewer Wrote:  

(27-11-2009 02:31 PM)Silenus Wrote:  Interesting Andre - thanks.
I assume the chlorine dioxide is to avoid infection ?

Yes, the chlorine dioxide will kill all (or as close as dammit to all) bacteria that might be present in your slurry. The low ph help to make the yeast less floculant, giving the chlorine dioxide beter access to all the yeast cells.

Your method described, also know as yeast rinsing, is very effective in removing trub and dead yeast cells, but won't kill any bacteria.

[masterbrewer]

Nope, for some reason, it doesn't. Look at the following for more info: https://wx5.registeredsite.com/user85649..._Clean.pdf

[Jeremy Wallis]

As an example of how effective chlorine dioxide is, Mike Heydenrych once had a batch of infected beer, retrieved the yeast from it, washed with chlorine dioxide and repitched the previously infected yeast into a fresh batch of beer and ... it fermented OK and wasn't infected !

Damn clever stuff this chlorine dioxide !

Jeremy.

[Silenus]

On Saturday I washed a California Lager yeast. Its so flocculant that I recovered very little yeast.
Besides adding lactic to lower pH - are there any other ways for making the yeast less flocculant ?

(27-11-2009 07:59 PM)Jeremy Wallis Wrote:  As an example of how effective chlorine dioxide is, Mike Heydenrych once had a batch of infected beer, retrieved the yeast from it, washed with chlorine dioxide and repitched the previously infected yeast into a fresh batch of beer and ... it fermented OK and wasn't infected !

Damn clever stuff this chlorine dioxide !

Jeremy.