question on reusing a yeast cake

[doodoobutter]

Hello, long time lurker here. I have somewhat of a specialized question here, which has broken me out of my lurking phase

I need some advice on reusing a yeast cake. We are in the process of getting the equipment to upgrade from 5 gallon batches to 15 gallon batches to save time in preparation for summer bbq's. Gonna be going the chest freezer and corny keg method for carbonation and serving.

At this point, we are planning to ferment 15 gallon batches in 3, 5 gallon ale pales (we are thinking of getting a 30 gallon conical plastic thing in the future). Using a yeast starter calculator, it looks like it's going to be a pita to make sure we have enough yeast. I don't like the idea of having to buy 2 or 3 vials and go through all of that work (plus risking infection along the way).

So I came up with this idea: One week before brewing 15 gallons, brew up a 5 gallon batch, making a starter out of one vial like we usually do. Plan to do the 15 gallon batch about a week after the 5 gallon batch brew day. So then we siphon the ale off of the yeast cake and into a carboy. So now the question is, if we split the leftover yeast into the 3 fermenters somewhat evenly, would that be enough?

I really like the idea of making a yeast starter that has a side affect of producing beer

 

[JonM]

If you can get uniform distribution of yeast, it should work. I checked Mr. malty, and 15 gal of 1.050 wort would need 7L, or 2-ish gallons of a starter. 5 should give you more than enough yeast.

 

[doodoobutter]

Thanks, this idea is looking good then. How do you suggest we get a uniform distribution of yeast? And should I worry about trub and other stuff, or just scoop it out with a thoroughly sanitized measuring cup?

Mark it 0.

 

[JonM]

If it was me, I'd give the dregs of the fermenter a good swirl and pour it, trub and all, into the next fermenter.

 

[doodoobutter]

Sounds like a good plan. I'll just give it a good stir and pour some into each fermenter. I had a feeling this was a good idea. I'm pumped that the new yeast starter technique is going to yield us 5 gallons of brew with minimal work. Thanks for the advice