Reusing yeast cake

[Reviled]

Hey guys, I re-use yeast cakes all the time, but generally what I do, is keg the batch, then dump onto the yeast cake ASAP...

What I was wondering, if I say, kegged the CAP i have, would I still be able to leave the fermenter with the yeast cake for a week or so before I pitch onto it? Or will I be risking it by doing this??

My thoughts are maybe the extra oxygen or something may stuff with it somehow? But im not sure...

[jt]

And this is how the yeast shaped up with a bit of wort

[Michael]

I have done this three or four times now, and no problems!

I do not know many many generations can go before it is I'll advised though. Maybe someone can answer this.

[denimglen]

What I've done once (and may start doing all the time) is ferment a low to lowish gravity batch, wash/rinse the yeast, and split it into a few jars and chuck them in the fridge. Then use one jar into a starter. This way you've got 2 - 4 samples that will all be in the same generation.

A little more work but worth a look maybe?

[Greig McGill]

Conveniently, Jamil and co have just done an entire show on this.

[Karle]

Here is a tutorial: http://www.homebrewtalk.com/f13/yeast-washing-illustrated-41768/

[Reviled]

I normally do do the whole wash and split into seperate bottles, then use them as desired for starters, however, if ive got a big cake of yeast to use, I dont bother with a starter cos theres no need!! Just dump the new unfermented wort straight onto the cake!! Especially with a lager as I generally do a 10litre starter for them anywho, and from experiance ive allways made the best cleanest lagers when theres a big fuck off cake in the fermenter to pitch on??

On average from every starter I make ill get about 3 brews from it just by pitching onto the cake.. But as i said above I do it ASAP after the beer on top has been kegged...

My WBC IPA was pitched this way, onto a gen III US-05 cake - will I get marked down for it? Well see...

[studio1]

in the case of an ale - is this massively over pitching?

[Reviled]

Apparantly so, however I personally havnt found any negative results from it! And ive also read that theres no such thing as overpitching, think of the positives, theres gotta be less chance of infection because of how much yeast there is? Theres definately going to be enough healthy cells to do the job? I reckon its all good...

[denimglen]

Nah, I believe there is such thing as overpitching.

All those yeast in the trub have just fermented a beer, you dump a fresh batch of beer on there and while there's enough cells there they're all tired, you need them to reproduce to make new healthy cells.

The reproduction cycle is where the yeast produce all their flavour compounds, even in a lager you still want some ester production.

I'm also not keen on doubling the amount of non-yeast trub in the batch that's dumped on the cake.

All IMO though, if it works for you - choice :-P

[JoKing]

I agree with you Glen.

The only reason you need more for lagers is because of the fermentation temperature. If you fermented at 20 degrees with an "ale pitch" of lager yeast, it would fully attenuate in the same way as Ale yeast. Would taste pretty shit though.

Over pitching isn't as bad as underpitching though - so if you were to do one over the other - I know which one I'd choose.

[Mike Neilson]

I would choose overpitch. Case swap was a full pitch of 1469 slurry from my NZ Ordinary bitter. I was going to post it in the NZ Case Swap but forgot. so that was a 20L starter for a 1.045 beer, opps my bad!!

[Stu McKinlay]

You know you have overpitched when your 1.100 barleywine gets to 1.015 overnight. And the temp jumped from 20c at pitching time to 28c the next day... the result: 20L down the drain.

Experience. Can't beat it for teaching yo'self a harsh lesson.