Starter from slurry question

[CWood]

Tough topic with possibly no perfect answer......so I'm trying to salvage some 6-week old wy2124 for a helles planned for tuesday. I used Mr. Malty to determine my viability was only 20% and I needed 830 or so ml to reach my lager pitch rate. I don't have that much, so need to make a starter. Thought it would be cleaner to use a portion of the 500 ml I have for starter, so with some simple math determined about a cup of slurry would produce around 100 bil viable cells. Thus, I pitched 1 cup slurry in 1200 ml starter wort with a plan to step that up to 1750 ml to reach optimal levels. Problem is, 24 hours into first step with one cup slurry I see zero signs of fermentation/replication. I've used this yeast quite a few times before and always get some signs, but usually start with a smack pack or use the slurry early enough to direct pitch. I also have 2308 and wl833 in fridge, but they are about same age. Should I start a new starter with another lager strain or just wait? If worse come to worse I have plenty of fresh cali lager yeast to pitch, but I really want a crisp helles. That helles yeast cake is planned for a dopplebock, so really prefer to use 2124. Advice, suggestions??

 

[flars]

Harvested yeast that is only 6 weeks old has a greater viability than 20%. I think these calculator estimates viability better than Mrmalty.
http://www.brewunited.com/yeast_calculator.php
https://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/

The information in this stickie will be of help to estimate billions of cells per milliliter to use the calculators. I will estimate 1 billion to 4 billion cells per ml depending upon which yeast I'm working with and how much non yeast material is present.
https://www.homebrewtalk.com/forum/...e-yeast-storage-procedure-with-photos.579350/

Hope this is of some help to begin answering your question.

 

[CWood]

Well shucks. My historical approach would have been to pitch the entire slurry and just expect a lag time. In an effort to become more "precise" I have been living by calculators. They seem to make sense with fresh yeast feom wyeast, wl, etc., but slurry pseudoscience is pretty loose. Unfortunately, I poured the remaining 2124 slurry out and I'm stuck with this starter, which is probably struggling due to too many cells in too little wort. Might be using 2308 or 833 instead. Straight slurry pitch. Thanks for the feedback.

 

[flars]

You can add more starter wort. Would be like starting over with the amount of yeast pitched. Are you using a stir plate? Often you will see no krausen with a stir plate. The Shaken Not Stirred method of propagation works well for large starters. Gallon pickle/etc jars work well for this. Aerate the wort very well before pitching yeast.

Some info on the SNS method.
https://www.homebrewersassociation.org/forum/index.php?topic=24460.0
Begin at reply #12.

 

[JONNYROTTEN]

I use slurrys almost exclusively and have never made a starter. Most are at least 6 weeks old. Not precise but unless your counting to 250 million I don't see how yeast could possibly be precise. Its all best guess

 

[CWood]

Yes, using a stir plate. 1 cup 6 week old slurry and 1200 ml starter wort. Planned on stepping up to 1750 or so today. With ales I usually don't pay as much attention, but going for a clean helles I like lots of yeast, thus the effort. You live and learn. Still might go ahead and add fresh wort up to 2000ml just to see what happens, but will most lily pitch a different yeast slurry. I have at least 500 ml of both 2308 and 833 and a boat load of cali lager yeast. Thanks again.