Splitting liquid yeast

[jonnymorris]

I've been reading Mr Malty and his description of how to make a starter using a White Labs vial of liquid yeast... http://www.mrmalty.com/starter_faq.php. I've also read a guide on splitting a liquid yeast to make multiple starters... http://uk-homebrew.tripod.com/id45.html. The second guide makes some assumptions that Mr Malty doesn't recommend (though I'm conscious that, whilst Mr Malty knows all there is about yeast, there may be a conflict of interest with respect to splitting White Labs yeast).

Q. Does anyone follow the splitting guide above or is there a more tried and tested method? I'm concerned that this guide may only double the cell count which is then divided into 12 vials leading to multiple batches of yeast in insufficient numbers.

Would it be better practice to ferment a 2L starter and then add more DME to re-ferment and increase the cell count in steps?

Any advice appreciated.

 

[pittsy]

Hi jonny , i do the splitting like mentioned above but when you have split them and now want to use 1 of them i then make up 1l with 70g dme for a new starter .

 

[bunkerbrewer]

Rather than splitting a vial, I find it much simpler to wash and reclaim the yeast from fermenter. You end up with plenty of yeast without having to step it up.

 

[graysalchemy]

I tend to top crop my yeast and then make 100ml vials which I freeze. When I need one I make up a starter a week or so earlier stepping it up. Each one can be reused and split 4-5 times so i keep a spreadsheet and number them that way I should have a pretty good supply of yeast for a fair few years to come. :thumb:

 

[PuggledPrune]

I'm interested to read this, I fancied trying WLP007 to make a PunkIPA-esque brew but really resent paying £6 for yeast.

GA - what do you use for 100ml vials?

 

[graysalchemy]

Sorry they are 50ml

I use =http://www.ebay.co.uk/itm/25-x-50m...ment_Lab_Supplies_ET&hash=item19d0e204d7these of ebay.

 

[PD]

or call in at your local health center and ask for a few urine sample bottles...free

or get diabetes...
or....

 

[bunkerbrewer]

Sorry they are 50ml

I use =http://www.ebay.co.uk/itm/25-x-50m...ment_Lab_Supplies_ET&hash=item19d0e204d7these of ebay.

Those are exactly what I currently use, too. Got a pile of 'em in the fridge!

I think in future I'll start using 125ml containers like this:

http://www.ebay.co.uk/itm/125ml-Pol...Equipment_Lab_Supplies_ET&hash=item257c580488

 

[PuggledPrune]

or call in at your local health center and ask for a few urine sample bottles...free

or get diabetes...
or....

Haha, my wife just chipped in saying she can get them from her work... I would never have thought but I guess they're sterile too.

I take it there is no problem with freezing it? Have done a bit of reading on it this morning and everyone seems to suggest keeping it refrigerated for no longer than 2 weeks. I don't brew enough for that kind of schedule...

Cheers. :

 

[graysalchemy]

If you are freezing then you need to mix it with glercerine and water

2parts yeast 1 part glycerine and 1 part sterile water

Give it a good shake and freeze. If your freezer is a modern one with a frost free mode then you may wish to pu the yeast in a polystyrene box as well to insulate them and maintain temps.

:thumb:

 

[bunkerbrewer]

I take it there is no problem with freezing it? Have done a bit of reading on it this morning and everyone seems to suggest keeping it refrigerated for no longer than 2 weeks. I don't brew enough for that kind of schedule...

Cheers. :

I've just bottled a Columbus Pale Ale which used reclaimed WLP001 from early February - it fermented brilliantly, better than the first generation.

I wouldn't worry too much about the 2-week thing, just be extremely clean and sanitary when reclaiming yeast. Trust your senses, if the yeast looks OK and smells OK, it's probably OK. Then make a starter, and taste / smell the starter as a final check.

 

[dennisking]

If you are freezing then you need to mix it with glercerine and water

2parts yeast 1 part glycerine and 1 part sterile water

Give it a good shake and freeze. If your freezer is a modern one with a frost free mode then you may wish to pu the yeast in a polystyrene box as well to insulate them and maintain temps.

:thumb:

That would make a good "how to" Alistair, hint hint.

 

[jonnymorris]

That would make a good "how to" Alistair, hint hint.

Agreed. I for one would find a How To on this topic very useful.

I make up a starter a week or so earlier stepping it up.

Maybe you could elaborate on this part when writing your How To? Do you ferment your defrosted yeast with a bit of DME and then top it up with more food (DME) after 12-18hrs or at high krauesen and repeat until...?

 

[graysalchemy]

When i Make a starter I use a wort of 1020 about 500ml with the 50ml sample yeast. Let it ferment out and settle pour off the liquor then start again but this time 1L and repeat. Continue this until you have the size of starter you require. I usually go for about 2-3L, hence why it takes a week or so, to do.

 

[jonnymorris]

I wouldn't worry too much about the 2-week thing...

If you go onto Mr Malty and try out his Pitching Rate Calculator you'll notice that the yeast viability decreases significant with time. A fresh sample is 97% viable whereas a one month old sample is only 72% viable.

 

[bunkerbrewer]

I wouldn't worry too much about the 2-week thing...

If you go onto Mr Malty and try out his Pitching Rate Calculator you'll notice that the yeast viability decreases significant with time. A fresh sample is 97% viable whereas a one month old sample is only 72% viable.

Yep, agreed - that Mr Malty calculator is a good resource, and I've got a copy of the "Yeast" book.

But don't forget the amounts we're talking about are huge compared to a single vial when reclaiming from trub - it can easily be the equivalent of 10 vials!

 

[jonnymorris]

But don't forget the amounts we're talking about are huge compared to a single vial when reclaiming from trub - it can easily be the equivalent of 10 vials!

Noted. Stupid question... is there any way to know how many cell you have? White Labs say that one vial contains 100 billion and that a 2L starter can double this to 200+ billion which is appropriate for 23L of wort at 1060. If you're reclaiming from the trub it's all going to be wild guess work is it not?

 

[bunkerbrewer]

Noted. Stupid question... is there any way to know how many cell you have? White Labs say that one vial contains 100 billion and that a 2L starter can double this to 200+ billion which is appropriate for 23L of wort at 1060. If you're reclaiming from the trub it's all going to be wild guess work is it not?

That's not a stupid question, maybe a complicated one :)

Yes, I'm sure that with a bit of effort you could estimate the number of cells. But it's going to be very variable, depending on lots of conditions, and how good you were on that particular day at separating yeast from trub.

So for me, it's wild guesswork, but let's be generous and call it intuition :) I know what a starter from a fresh vial looks like, and if I use 4 - 6 50ml vials of my reclaimed yeast the starter performs better. I'm not too worried if I end up overpitching, if that's even possible at this scale.

A final point about age and viability - the countdown resets when you're reclaiming yeast, as they're newly hatched. White Labs have four months on the vial before the "best before" date. I realise that's because they can package in laboratory sterile conditions, but it's still a lot longer than 2 weeks... :)

Anyway, it works for me.

 

[graysalchemy]

I'm not too worried if I end up overpitching, if that's even possible at this scale.

You have obviously not seen my picture of my exploding stout :lol: :lol: .

Over pitching will result in less of a growth phase which inturn reduces the amount of esters produced. May not be a problem for a stout or an APA but would affect the taste of an English bitter.

:thumb: :thumb:

 

[bunkerbrewer]

I'm not too worried if I end up overpitching, if that's even possible at this scale.

You have obviously not seen my picture of my exploding stout :lol: :lol: .

I have, it's awesome. Post it again, you know you want to :)

Over pitching will result in less of a growth phase which inturn reduces the amount of esters produced. May not be a problem for a stout or an APA but would affect the taste of an English bitter.

:thumb: :thumb:

Yep, that makes perfect sense. I don't think I've seen anything which actually quantifies what overpitching is, though.

Maybe someone here knows, or can check my back-of-a-fag-packet reckoning. Say my reclaimed yeast is actually 50% trub, worst case, and I've got about 15-20ml of this stuff in each 50ml tube, and I use 4 - 6 of these for a 25L brew, in a 1L starter.

So if in total I've got double the cell count of a new vial, my 1L starter won't be big enough to increase this 2x, just wake the buggers up.

So I'm probably only pitching the equivalent of 2 or 3 new vials? Is that overpitching?