I plan to cultivate 540 billion cells for 6 gal. of high gravity wort. According to Brewers Friend pitch rate calculator, for my yeast I need to propagate 2 starter steps. After the first step fermentation is complete, is it best to just add a second batch of wort, or should the old wort be decanted away first?
How high OG? There may be an alternative.
My OG is 1.100", and my basis for cultivating 540 billion cells is from John Palmer’s “How to Brew” recommendations. I have a 2L flask, so I’m limited on how large of a starter I can handle.
I’ve done what you’re trying to do both with a large starter and with the slurry from a low gravity batch. The slurrybgave me far better results than the starter. So, if it’s possible, first brew a batch with a 1.040-50 OG. Then put your high gravity batch on that yeast cake. To answer your original question, yes you need to decant spent wort and add fresh wort in a multistage starter.