Author Topic: Yeast cake rehydration  (Read 2086 times)

Offline pyrite

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Yeast cake rehydration
« on: March 31, 2011, 06:22:30 AM »
What method do you use to rehydrate a yeast cake and prepare it for pitching?

I'll be transferring a 6% lager from primary to the secondary this weekend, and wanted to use the yeast cake right away in another lager.  What method would you suggest to get that yeast healthy for next pitch?   
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Offline hokerer

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Re: Yeast cake rehydration
« Reply #1 on: March 31, 2011, 07:16:48 AM »
What method do you use to rehydrate a yeast cake and prepare it for pitching?

I'll be transferring a 6% lager from primary to the secondary this weekend, and wanted to use the yeast cake right away in another lager.  What method would you suggest to get that yeast healthy for next pitch?   

Wouldn't think you'd need to do anything.  Just rack the new batch into the fermenter right on top of the cake.
Joe

Offline denny

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Re: Yeast cake rehydration
« Reply #2 on: March 31, 2011, 07:36:03 AM »
Wouldn't think you'd need to do anything.  Just rack the new batch into the fermenter right on top of the cake.

If you were using an ale yeast, I'd suggest using only part of the slurry.  But since you're doing a lager, I'd go with the advice above.
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Offline tschmidlin

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Re: Yeast cake rehydration
« Reply #3 on: March 31, 2011, 09:11:31 AM »
How long has it been sitting, and what is the gravity of the new batch?
Tom Schmidlin

Offline bluesman

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Re: Yeast cake rehydration
« Reply #4 on: March 31, 2011, 10:05:41 AM »
Yeast cakes should be used within a week or two otherwise I would suggest making a starter from it. Go to mrmalty.com and estimate the quantity of slurry required and pitch on that ideally within a day or two.
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Offline pyrite

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Re: Yeast cake rehydration
« Reply #5 on: March 31, 2011, 11:23:37 AM »
How long has it been sitting, and what is the gravity of the new batch?

So from what you guys are saying, the yeast cake is ready to go to work again with out any nutrients or any type of help?

The lager has been in primary fermentation for 25 days @ 48F, with an included D-rest for 3 days @ 65F.. The new humulus lager hoppy lager batch will have an expected O.G. of  1.060. 
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Offline tschmidlin

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Re: Yeast cake rehydration
« Reply #6 on: March 31, 2011, 11:36:54 AM »
I think it will be fine, there should be plenty of viable yeast there to finish the new batch if you just rack on top of the cake like hokerer/Denny were saying.  I use nutrients in all of my batches, but other than that I don't think you need to do anything special for this yeast cake.
Tom Schmidlin

Offline Kirk

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Re: Yeast cake rehydration
« Reply #7 on: March 31, 2011, 12:44:10 PM »
+1 to all, only to say that if you want to use a clean container, just swirl it (after racking your beer of course) and pour it into the new one.
Kirk Howell

Offline jeffy

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Re: Yeast cake rehydration
« Reply #8 on: March 31, 2011, 12:50:29 PM »
You could pour it into a sanitized jar and let it settle.  That'll give you time to clean the fermenter and let you use the MrMalty site to actually measure the amount to use.
That said, when I brew back to back batches I often syphon the finished batch out of the primary and then fill it with the new wort right onto the yeast.
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Offline pyrite

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Re: Yeast cake rehydration
« Reply #9 on: March 31, 2011, 02:41:48 PM »
Thanks all, for the suggestions.

I will pitch the yeast cake as is.
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Offline Will's Swill

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Re: Yeast cake rehydration
« Reply #10 on: April 02, 2011, 10:14:33 AM »
Probably a stupid question, but is it preferable to use the yeast cake from the primary or the secondary (assuming a secondary is used of course)?  I would think the yeast population would be higher from the primary, but in the secondary I would think the yeast sediment would be "cleaner" (i.e. less unwanted trub).
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Offline denny

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Re: Yeast cake rehydration
« Reply #11 on: April 02, 2011, 10:16:00 AM »
OTOH, if you use the secondary, you're selecting the less flocculant yeast.  All if which is a way of saying it doesn't really matter all that much.
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Offline pyrite

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Re: Yeast cake rehydration
« Reply #12 on: April 05, 2011, 07:11:50 PM »
Update: Less than one hour after pouring the new wort right on top of the lager yeast cake, the violent fermentation created enough force to pop the blow off tube right off the carboy.  I've never seen that before, especially since it's fermenting at a constant 43F.  Only 3 full days since the inoculation and it seems to be almost done.   
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Offline bluesman

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Re: Yeast cake rehydration
« Reply #13 on: April 05, 2011, 07:16:38 PM »
Update: Less than one hour after pouring the new wort right on top of the lager yeast cake, the violent fermentation created enough force to pop the blow off tube right off the carboy.  I've never seen that before, especially since it's fermenting at a constant 43F.  Only 3 full days since the inoculation and it seems to be almost done.   

Sounds like your making beer. ;)

Congrats. Hope it turns out well for you.  :)
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Offline gmac

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Re: Yeast cake rehydration
« Reply #14 on: April 05, 2011, 07:30:41 PM »
If you were using an ale yeast, I'd suggest using only part of the slurry.  But since you're doing a lager, I'd go with the advice above.
What's the rationale for only using part of the yeast cake for an ale?  I know lager need larger starters but what's the downside to using a large starter for an ale?