cpa4ny wrote:Elderberry wrote:
Great idea, though it definitely takes some foresight. I rarely remember to make a starter far enough in advance to decant, if at all.
So you separate the two starters AFTER you decant? How do you determine your volume/yeast count?
To me - good part of brewing is planning (I am sure Nesto will second that)
I certainly separate the two starters
before I decant - otherwise all my yeast count would go haywire.
In the example above, the post-fermentation yeast count in the yeast to be stored would represent 1/4 of Mr Malty's calculated value.

Indeed! Planning is a favorite of mine
I wrote a blog post about harvesting yeast a little while ago...
http://www.sycamorecreekbrewing.com/2014/03/my-billion-little-workers-or-how-i.htmlI linked to a nice video of someone harvesting yeast. As I noted in my post, I do it a little differently - I harvest from a full fermenter (which you can't really do unless you have a conical) and I use beer to store it. There is a raucous HBT post I linked to about rinsing and storing yeast... almost as long as the Braumeister post on HBT! I will concede that White and Zainasheff (in their Yeast book) tell you to use water to rinse and store yeast in.
A few details I left out of the post...
1. Make sure all the jars you use have been cleaned and sanitized!
2. You can estimate your yeast count based on volume. For my first try with WLP037 (the seasonal Yorkshire Square Ale yeast) I used 210ml mason jars and calibrated so I knew each cm of yeast cake was 26ml. I used the
Mr. Malty nominal value of 2.5 billion cells per ml (use the "pitch yeast from slurry" tab). I let it settle overnight before I measured and I harvested about 130 billion cells in each jar.
3. I assumed a 21% viability loss per month when calculating the starters I needed. Was able to do 3 additional brews (2 beers and a cider) over the following 2 months. So theoretically I was around 60% viability for the last brew - a barleywine. And it fermented cleanly and thoroughly from 1.096 down to 1.014.
In addition to the economic advantages, I've heard several experts say it takes a couple generations for a yeast to hit it's peak, so I plan to do more harvesting. You do kind of need to plan out your brew calendar and make a yeast plan (I sense a new spreadsheet!). I can't decide whether I'll use this method or cpa4ny's pre-harvesting method in the future. It will probably depend on how many brews I plan with a single yeast. Just doing 2, then definitely cpa4ny's method. But for something like I just did - a 4 brew run with one yeast - I'll harvest from the primary fermenter to get the increased amount of yeast. It only took about 30 minutes of actual working time to harvest, rinse and divide up among small mason jars for storage; a bit longer when you count the settling time.