Author Topic: Re-using Yeast for Starters  (Read 1865 times)

Offline tomsawyer

  • Senior Brewmaster
  • ******
  • Posts: 1694
    • View Profile
Re: Re-using Yeast for Starters
« Reply #15 on: December 06, 2011, 03:13:12 PM »
It will last a long time, potentially a very long time if you use distilled water.  But after 3 months you might want to make a starter or pitch extra.
Good to know. Thanks, Tom! Looks like I've been throwing away good yeast!
You're just stimulating the economy.
Lennie
Hannibal, MO

wildknight

  • Guest
Re: Re-using Yeast for Starters
« Reply #16 on: December 07, 2011, 06:53:05 AM »
I like to rinse the yeast cake 3-4 times with boiled, cooled water.  This lets me get the trub out (what falls out first) and the dead cells (what falls out last).  Then, I calculate the pitching rate using the lowest setting for trub on the MrMalty app.  If it is older than a week, I give it a little wake up juice starting the morning of brew day (to be pitched ~ 12 hours later).

I will save yeast from APA's, but generally not IPA's as I late hop them heavily and go high gravity.  This really stresses the yeast and coats them significantly with hop oils.  I believe the theories, as from my own experience it takes a lot more effort to clean yeast cakes from these types of beers, and I observe a lot more dead, floating cells during the washing process.  If I dry hop in the primary fermenter, then I don't even consider saving the yeast cake.  It's nearly impossible to get the yeast clean.  If you transfer to secondary, then you can dry hop all you want without ruining your yeast cake.  However, the trade-off is that you have to let fermentation complete and wait for the yeast to completely flocculate and settle otherwise you will begin selecting for early flocculators.  This prevents you from throwing in the dry hops when fermentation is 2/3 complete, thereby letting the yeast soak up any oxygen that comes in with the hop pellets. 

Usually, I use the american yeast strains on hoppy beers.  Since these only cost $1-2 per dry packet, I don't worry about not saving the yeast.  For all other beers I use specialty, liquid strains and put in the extra effort to keep the cakes going. 

Offline Pi

  • Brewer
  • ****
  • Posts: 355
  • "I would never trade tomorrow for today"
    • View Profile
Re: Re-using Yeast for Starters
« Reply #17 on: December 07, 2011, 07:59:20 AM »
On Sunday I racked a stout using Wyeast 1084. I had a yeast cake with about 1/4" of beer on top. I swirled the carboy around to mix with the beer and to loosen up the cake and then poured it into a 12oz. bottle. MrMalty says use 3.8oz. in my Scotch Export. Should i be mixing as stated, or should i harvest only cake? What role does O2 play at this point?
Also, when You talk about washing the yeast, could you elaborate how this is done? I mean, is it simply a matter of mixing with clean water; settle out and rack off the liquid in suspension?
Primary:Stella Rosemary IPA
Lagering: Sto Lat Gratzer
Drinking: Whenever I'm not working or driving

wildknight

  • Guest
Re: Re-using Yeast for Starters
« Reply #18 on: December 07, 2011, 08:18:58 AM »
In a nutshell, stuff that falls (well shaken, no obvious clumps) within 10-15 minutes is trub.  Stuff that won't fall out in 12-24 hours (in the fridge) is dead yeast.  Remove both using sterile/boiled water.

Here is a nice, detailed podcast on the subject:  http://www.thebrewingnetwork.com/shows/543