Splitting liquid yeast

[jonnymorris]

To quote myself paraphrasing Mr Malty...

One vial contains 100 billion cells and a 2L starter can double this to 200+ billion which is appropriate for 23L of wort at 1060.

Ergo, pitching the equivalent of two new vials sounds about right. Not sure of the rest of your logic though which is pretty much my point... how do you know how much you're pitching?

 

[Good Ed]

To quote myself quoting Mr Malty...

One vial contains 100 billion cells and a 2L starter can double this to 200+ billion which is appropriate for 23L of wort at 1060.

Ergo, pitching the equivalent of two new vials sounds about right. Not sure of the rest of your logic though which is pretty much my point... how do you know how much you're pitching?

Short of setting up the facilities of a small lab as described in the Yeast book, you can only really rely on volume, and base it on the volume in a white labs vial that has ~100bn cells. That's why I always start with a 2L starter and 1 vial of WLP to give me ~200bn cells, I then split that in two, put 1 back in the fridge and step up the other to however much I need. This is of course not very accurate, but I have 4 white lab yeasts on the go this year doing this process, and will start with new yeast again next year or sooner depending on how much I use one particular type. You really need the Yeast book to understand the process of stepping up, what size of starter to use and yield factors etc.

 

[bunkerbrewer]

To quote myself paraphrasing Mr Malty...

One vial contains 100 billion cells and a 2L starter can double this to 200+ billion which is appropriate for 23L of wort at 1060.

Ergo, pitching the equivalent of two new vials sounds about right. Not sure of the rest of your logic though which is pretty much my point... how do you know how much you're pitching?

I take your point - you're absolutely right, I don't know for sure. All I can really talk about with confidence is what happens when I brew.

As I got used to my system, I was able to increase the brew length from 19L to 25L without any extra effort, so I did :)

I found out the hard way that the amount of yeast which worked for 19L is not enough for 25L - I had all the classic problems associated with underpitching. Now, with a few tubes of reclaimed yeast I get a reasonably short lag time, healthy ferment and expected attenuation (I measure this for every brew).

Like I said, I've read White & Zainasheff "Yeast" book, and the science geek in me would like to know cell counts etc, but this process actually works for me (based on the relatively little experience of 14 AG brews). I should also say that I don't drink much strong beer, so all of my brews are in the 1.035 - 1.050 OG range. "Doing it by instinct" probably wouldn't work if I brewed a 1.065 monster.

 

[graysalchemy]

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?

I wouldn't have said so I usually use 50 -100 ml of yeast and grow it up to 2-3 L for a 60L brew, sometimes a bit less if the yeast is really active and going for it.

 

[bunkerbrewer]

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

I wouldn't have said so I usually use 50 -100 ml of yeast and grow it up to 2-3 L for a 60L brew, sometimes a bit less if the yeast is really active and going for it.

Good to know, many thanks :thumb: