Yeast ranching increases flocculation?

[william_shakes_beer]

I have been harvesting from split starters for about 3 years now. This brewing season I noticed that all my strains now take 48 hours to show signs of fermentation, and flocculate much more quickly then before. Is it possible that my harvest process of pour/crash/decant/repeat that yeilds a tube 2/3 full is selecting for the most flocculant cells and shifting my strains? They all ferment fine, so this is not a problem, just wondering if anyone else has noticed this phenomenon. I ask because yesterday I did a double batch. Cooled and pitched half the starter to the first fermenter, then stepped the starter while I cooled the second half. The starter step took off within an hour or so.

 

[trentm]

That's interesting. I understand that flocculation is the easiest trait to select for. I'm not sure I fully understand your process but if you are somehow saving yeast that floc early your strain will quickly become more flocculant. That would also explain the late start to your fermentations. Your highly flocculant yeast may be dropping to bottom where they are having are hard time getting going. You could try stirring or shaking to keep them in suspension. Also, if you can, try to save yeast that have dropped out late. That should select for yeast that are less flocculant.

 

[flars]

Lag time

 

[william_shakes_beer]

My harvesting process in more detail for trentm:
1. Complete fermentation on selected starter
2. Swirl and pitch to the wort, retaining an appropriate amount at the bottom of the E flask
3. Pour slurry into 2 preform tubes
4. Decant eflask
5. Decant preforms
6. Swirl and refill preforms
7. repeat steps 5 and 6 until slurry is approximately 1/3 to 1/2 of preform, or until slurry is exhausted