Yeast starter help again

Alright so I'm going to be brewing a beer with a og of 1.090 so I know I need a big starter. I understand how to make a normal yeast starter but for a high gravity beer I'm still not so sure. From watching a video from Northern brewer they say for a high gravity beer you need to do a two-step propagation. They say to do this you prepare and incubate a starter and decant the spent wort. I think I'm clear this far. Then add an equal volume of boiled cooled starter wort to the yeast slurry in the decanted flask and then repeat the steps for incubation. Ok so here is my ?. After I decant the spent wort and add more starter wort to the slurry do I have to pitch more yeast?

 

Nope, you're just growing more yeast from what you have. The initial yeast has depleted the food/wort you've given it. So now you're adding more wort so the yeast can continue multiplying.

 

No. When you decant off the spent wort, the yeast cells you just grew are sitting there in the flask waiting for the fresh meal.

1.090 ale or lager? For a 1.090 ale, I'd consider brewing a 5-gallon batch of lower gravity beer using the same yeast and then use about 50% of the the yeast cake for the 1.090 batch. For a lager that big, I'd certainly go that route and use the whole cake. The starter for a 1.090 lager will be huge even with a stirplate.

 

Thanks guys. It's an ale. So if I do a 1500ml starter decant and repeat I should be ok?

 

Here is a link to a yeast starter calculator that is handy for stepped starters. Just follow the steps and look at the numbers it gives you.
http://www.brewersfriend.com/yeast-pitch-rate-and-starter-calculator/

 

After your first starter is done fermenting, cold crash the yeast at ~ 45F for 24 hours. This will cause all the yeast to drop out of suspension. You can then easily pour off the wort. Leave the flask out to get back to room temp. In a pot on the stove create more wort and add this back to your flask. Throw it back on the stir plate for another 18 or so hours. Use the brewers friend calc to see if you will have enough yeast and repeat if necessary.

Good luck


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This is the plan I use for making bigger beers. Without a massive starter vessel, like a 5L flask, its just not that easy to make a starter big enough. I have a 3 gallon carboy I use to make a 2.5g batch of beer, similar but smaller to the big beer I want to make, then use the yeast cake from that to make the bigger beer. 2 advantages, 1, more beer! 2, enough yeast. Disadvantage, takes longer to make that bigger beer because you need to wait for the first to finish fermenting, tho I don't see this as that big a disadvantage because that bigger beer should sit and age longer anyway, and I'll have the smaller beer to drink while I'm waiting 😁!

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Thanks