Lager Yeast Pitching Rate

[bytor2012]

I have this recipe for a Helles Bock that I've been wanting to make and I ran into a slight hiccup. The OG is 1.069. According to Beersmith and mrmalty.com I'm going to need 4 smack packs and a 3.5L starter. Would it be possible to get the same amount of viable cells from 1 smack pack by using a 2L starter, pitching the yeast, fermenting, cold crashing, decanting the spent wort, and repeating the process 3 or 4 times? Is this achievable or do I need to buy 3 more smack packs?

 

[brewmeister13]

Yes and no. If you grow a 2L starter and then toss all the yeast back into 2L you can actually do more harm than good. You won't be growing more yeast and you can negatively affect the fermentation characteristics of the strain. You can, however, grow a 2L starter, then split it into four separate batches and grow each of them into 2L starters and come out with roughly 548 bill cells (I'm assuming no stir plate), which should be good. I prefer brewersfriend for yeast calculation. I find it easier to see the actual numbers.

 

[sfgoat]

Best bet is to go to a bakery and ask for a glaze buckets. They are about 1-2 gallons, food grade and works perfectly on a stir plate. Then you can make a full size starter and the bakerys usually are happy to give them to you.

 

[bytor2012]

Ok. According to brewersfriend, I can do a three stage propagation and reach the amount of cells required. I'm also interested in your suggestion of splitting a 2L starter into 4 separate starters. I have enough growlers (wish I had enough stir plates). Could you explain why the yeast would be healthier this way as opposed to the other?


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[sfgoat]

The problem with stepping up the starter that many times is that with each step there is significantly more yeast in the vessel. So by the 3rd step it fills a lot of the flask so there is less wort and with all that yeast the wort just gets devoured too quickly so the yeast doesn't even reach the propagation stage. Better to do it all at once or in several batches instead of the steps you are describing. If it was a session beer then I'd say step it but it's a bigger beer and needs more yeast propogation. This is why I use the glaze buckets for my lager starting.

 

[brewmeister13]

Could you explain why the yeast would be healthier this way as opposed to the other?

I'm going to be lazy and let someone else do the explaining. https://www.homebrewtalk.com/f163/stepping-up-yeast-starter-326077/ Post #8 is the one I would suggest reading.